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Chaos Corona for 3ds Max => [Max] General Discussion => Topic started by: cjwidd on 2020-03-11, 06:34:02

Title: Tonemapping - Plz Halp
Post by: cjwidd on 2020-03-11, 06:34:02
Bit of a rant - or a cry for help - but I'm either approaching lighting or tone mapping totally incorrectly; it is absolute guesswork every time, and rarely is it 'photorealistic'.

Looking at Juraj's work, Bertrand's work, etc. - there is a consistent look and quality with each project and I'm just not convinced (for now) that they are also, just guessing; I assume they have some sort of method - a procedure. For example, when I worked in a studio, we had a *very* strict method, and it produced a consistent result, but with Corona I feel like I'm guessing once I get to tone mapping.

In Ludvik's, Time to ditch sRGB/Linear as default (?) (https://forum.corona-renderer.com/index.php?topic=14958.0) thread, it is mentioned:

Right now, we perceive linear sRGB as the default, the start line, and we then work with some parameters to bring that sRGB close to photo-realism. We manually have to twist some knobs in order to take a picture, which by default is not realistic to our eyes, and using some controls, turn it into image that our eyes perceive as photorealistic. So why not just skip this process and have renderer(s) by default output same ranges as cameras do. [...] There's no significant reason why renderer should not work the same way. Not by having a dropdown where you can pick numerous response curves, and one of them is called photorealistic, but instead by having it defaulting to a camera, with an option to switch to a very special mode, which will make your output less realistic, but compose-able in post.

This is a very attractive proposition and it speaks to the issue I am referring to. Regardless of whether such an implementation is feasible or not, I'd like to learn how to produce images that are of the quality we expect from the Corona Gallery and I just haven't seen strong tutorials - free or paid - demonstrating such an approach.
Title: Re: Tonemapping - Plz Halp
Post by: Jpjapers on 2020-03-11, 10:53:21
Its not just tonemapping that makes those guys renders look amazing every time. Its attention to detail at every stage and questioning how something actually looks in reality vs what we imagine it looks like. Lacking some minute details is enough to make your brain subconciously question an images' realism so the answer to the question "How do i make it look like [insert artist here]" is usually "Hard work and practice" when you really break it down. I get what you mean though with regard to the consistency of some people images. I think its maybe to do with everyone having a preference of HDRI for a given look, combined with repeating and refining your preferred process over time.

I dont think you need to worry though. Your renders are always awesome!
Title: Re: Tonemapping - Plz Halp
Post by: maru on 2020-03-11, 10:55:43
1. "Turn linear sRGB into digital camera product"

Quote
having it defaulting to a camera, with an option to switch to a very special mode, which will make your output less realistic, but compose-able in post.

You can get this by rendering your image at the default settings, then enabling LUT and picking one of the 3 Kim Amland's photographic LUTs. They are captured from real life digital cameras.
Then you can optionally reduce the strength of the LUT to ~0,8 (to your own taste) and play with highlight compression and filmic values (again to your own taste, to reduce highlight burn).


2. "I want to produce images like the masters"

Quote
This is a very attractive proposition and it speaks to the issue I am referring to. Regardless of whether such an implementation is feasible or not, I'd like to learn how to produce images that are of the quality we expect from the Corona Gallery and I just haven't seen strong tutorials - free or paid - demonstrating such an approach.

I am afraid this is not as easy as just following one or two tutorials. Artists have their own secrets. Some of them definitely use Photoshop or other post tools to adjust images in addition to what is done in the VFB, not only by changing the overall tone mapping/coloring, but also locally, e.g. by making some areas more or less noisy, brighter/darker, more clear/blurry, etc.

Title: Re: Tonemapping - Plz Halp
Post by: cjwidd on 2020-03-11, 20:30:32
@Jpjapers, thank you so much for your thoughtful and detailed response, and @Maru thank you for your advice - I really appreciate it :)

I think both of your responses more or less encapsulate the truth of the matter, which, as you say @Jpjapers - it boils down to hard work and practice. I want to be clear, I'm not grasping for a magical solution, I'm not pining for a "make this look good button", but I do imagine there are techniques - like using False Color LUTs, etc. - to help narrow the path toward an image that speaks to the quality of the 'masters'.

I would also say that I have **scoured** the forums for many of the relevant tools that have been shared here (e.g. Dubcats camera LUT dumps, fStorm LUTs, Adanmq false colour LUTs and log space filmic LUTs, specular to IOR cube (for materials - Quixel Bridge does this by default now), Dubcats ACES emulation recommendations, etc.) and gathered many high quality (?) HDRIs, including Jørgen Herland and Peter Guthrie.

I assume then, that if I am working with high quality tools, then the onus is on me to get the most from the tools which are already doing their part to help.

I'll take a look at the resources you linked @Jpjapers, they seem promising - thank you!
Title: Re: Tonemapping - Plz Halp
Post by: Jpjapers on 2020-03-11, 22:36:23
@Jpjapers, thank you so much for your thoughtful and detailed response, and @Maru thank you for your advice - I really appreciate it :)

I think both of your responses more or less encapsulate the truth of the matter, which, as you say @Jpjapers - it boils down to hard work and practice. I want to be clear, I'm not grasping for a magical solution, I'm not pining for a "make this look good button", but I do imagine there are techniques - like using False Color LUTs, etc. - to help narrow the path toward an image that speaks to the quality of the 'masters'.

I would also say that I have **scoured** the forums for many of the relevant tools that have been shared here (e.g. Dubcats camera LUT dumps, fStorm LUTs, Adanmq false colour LUTs and log space filmic LUTs, specular to IOR cube (for materials - Quixel Bridge does this by default now), Dubcats ACES emulation recommendations, etc.) and gathered many high quality (?) HDRIs, including Jørgen Herland and Peter Guthrie.

I assume then, that if I am working with high quality tools, then the onus is on me to get the most from the tools which are already doing their part to help.

I'll take a look at the resources you linked @Jpjapers, they seem promising - thank you!

Id still say the biggest thing to always keep in mind is the reality aspect of whatever youre doing. If youre making a lamp light, do some googling and find out the lumens output of a lamp bulb. If you ever have to boost the sun intensity. Something else is wrong.  If you ever have a light set to crazy intensity to make it look realistic, something else is wrong. It sort of helps to just keep asking why when you reach those points. It often helps to set everything back to defaults to rebalance your image if you get to a point where youre making a completely unrealistic guess.

But as i say, your renders look great already! Everyone has a style. I certainly have a method when it comes to lighting but the longer you play around with things the more youre likely to develop your own style instead of trying to emulate others.  I didnt think you were asking for a magic button but it really does just boil down to understanding the software, its relation to real world values and knowing the physically accurate values and methods that you should be using to achieve realism. Yes CG is a playground and we arent bound by physics. But if youre going for realism, you should adhere to realism and the rules which apply in the real world.

As Da Vinci said "Simplicity is the ultimate sophistication".
Title: Re: Tonemapping - Plz Halp
Post by: cjwidd on 2020-03-12, 00:49:21
Thanks man, I really appreciate that, and I definitely feel you with that DaVinci quote ❤️

It often helps to set everything back to defaults to rebalance your image if you get to a point where youre making a completely unrealistic guess.

Haha, yeah I definitely find myself doing this from time to time - get too far down the rabbit hole and just have to reset.

That is a good point about light intensity, and something I should probably do more to be mindful of. I've mostly been in the habit of working with W/(sr.m^2)(?)

Also, thank you for that false color LUT you shared, I really like it! I've used a couple other ones, but I prefer the color code with that one.
Title: Re: Tonemapping - Plz Halp
Post by: Jpjapers on 2020-03-12, 10:14:40
I've mostly been in the habit of working with W/(sr.m^2)(?)

Ive been questioning which units are best to use for a while. I prefer using Lumens because lighting manufacturers pretty much always list lumens as part of their spec sheets.
In my opinion, lumens work alot better as the light output stays the same regardless of the radius, it just becomes more focussed the smaller it gets whereas W/(sr.m^2) is dependent on the size of the light.
Title: Re: Tonemapping - Plz Halp
Post by: Fluss on 2020-03-12, 19:28:39
I've mostly been in the habit of working with W/(sr.m^2)(?)

Ive been questioning which units are best to use for a while. I prefer using Lumens because lighting manufacturers pretty much always list lumens as part of their spec sheets.
In my opinion, lumens work alot better as the light output stays the same regardless of the radius, it just becomes more focussed the smaller it gets whereas W/(sr.m^2) is dependent on the size of the light.

What about directionality? I'm asking myself for a while about that... Light power does not seem to take that parameter into account
Title: Re: Tonemapping - Plz Halp
Post by: cjwidd on 2020-03-12, 20:31:21
@Jpjapers this is a great example of what I was originally posting about - I had no idea lumens wasn't affected by the light dimensions (?)
Title: Re: Tonemapping - Plz Halp
Post by: Jpjapers on 2020-03-12, 23:38:37
@Jpjapers this is a great example of what I was originally posting about - I had no idea lumens wasn't affected by the light dimensions (?)

Well i had a few years of experience in commercial and retail lighting so i had to have a very basic understanding of real-world info on theoretical light measurements.
Ill try and give a brief and probably misguided rundown and im sure theres things here that are completely misunderstood or mixed up so ill gladly take corrections if ive got it wrong. I know Ondra and Juraj have talked about this in various threads.

First of all Each of the measurements have a specific function and arent just a personal preference thing.

Lumens is a measure of how much total light a luminaire will emit at the source (luminous power) so it isnt dependent on how big the light is because its an absolute.  So literally "How bright is this bulb?". Its required by law on most lighting spec sheets because there are minimum required lux levels across various spaces by law so this info should be available for every light you could need to include in your scene. I like working with this one because you can be sure that regardless of how big the light is, if you know the lumens value, you can be sure its accurate.

Lux The measure of light output as percieved by your eye ( measures exitance at the source and illuminance at the surface). Its a photometric measurement of how lumens are spread across a surface.

So if you run IR and set the intensity units to something like 2000 w/sr.m^2 and change the radius, youll see the scene get brighter. Whereas lumens, if you make the light bigger, the same amount of light output is spread across a larger area like when you focus and defocus a lens on a torch or a headlamp. See below. The torch doesnt get brighter its just more focussed resulting in higher lux but the same lumens.

You could have 1 really small bright light in your house and get a high lux level on your floor. Whereas if you wanted to light a warehouse with those same lights, you would need alot more of them to achieve the same lux level despite the lumens output of the light being the same. 1 lux is 1 lumen per square meter. I tend to use lux for things like mimicking daylight because its easy to measure lux with a light meter.




Watts per steridean per square meter is a radiometric measure of the lights percieved brightness and it depends on the size of your light so for every size increase, you'll get a power increase. It measures radiance which is sort of how much of the emitted power the eye is recieving. Id like to understand this a bit better.

Candelas (cd) measure luminous intensity. That is, how bright is the light at the source. 1 candela for a wax candle flame is accurate. It uses something called the steridean value which is basiccally the cone of the light. I'm not certain on this one. Again id like to know more.

Here's a little diagram of how the measurements relate to each other

(http://homepages.inf.ed.ac.uk/rbf/CVonline/LOCAL_COPIES/RYER/fig7-4.gif)


What about directionality? I'm asking myself for a while about that... Light power does not seem to take that parameter into account

I wish there was a corona light meter like the old one in mental ray. Then i could actually do some real tests because theres some stuff about Steridean I dont understand (which i think is the technical term for directionality?) and i thought based on the descriptions of the units, the directionality would affect them differently . I asked a fair few years ago about the implementation and maru had some quotes from somewhere. Hopefully one day we might see some sort of implementation when the big list of future bugs/features is running dry. Unfortunately now mental ray is gone you cant really do much.

Quote
You can paste the value which you obtain in W/(sr.m^2) from image pixel (or from your lightmeter in real life) into Corona light intensity and then change light units to Lux. But from what I understand this still requires some guessing and is more of a "workaround" than real light metering. Unfortunately, it looks like a proper implementation of light metering tools will be required for this to work.

Another idea is to use native 3ds Max photometric lights as Corona supports them. You can then switch to Mental Ray and use pseudo-color exposure controls or other tools which are built into 3ds Max to get the desired light intensity, and switch back to Corona again.

Quote
it seems that the easiest way to recreate real light in Corona (or any other renderer probably) would be to find what is the light's intensity in lumen (it should be on the box/package if this is some regular light bulb, or there should be some manual with such info if this is some more advanced/photographic light). If you know value in lumen, then you should be able to simply paste that value into Corona light. If you know the power of light in W, and you know the light's efficiency, then you should also be able to convert this into lumen. Here is an example calculator: http://www.rapidtables.com/calc/light/watt-to-lumen-calculator.htm

There are also some obstacles like light color, or light shape, so it looks like this is always some simplification.

Quote
If you are not after scientific precision, I would suggest you taking a number of reference photos so that you would know the camera exposure values (shutter speed, iso, f number, etc), then recreating these exposure values in Corona and tweaking light source intensity so that the image is visually similar to the reference photos. Unfortunately I don't think there are currently any easy ways of doing this.
Title: Re: Tonemapping - Plz Halp
Post by: cjwidd on 2020-04-22, 10:22:33
@Jpjapers at the very least your summary seems like a good shorthand for how to think about these different parameters. You mentioned earlier:

If you ever have a light set to crazy intensity to make it look realistic, something else is wrong.

I was going back and forth with LightMix and realized I was boosting a W/(sr.m^2) light source to >11,000k and then remembered your comment.

Your summary post seemed to indicate that W/(sr.m^2) measurement may include a perceptual component - so there can't really be a 'ground truth' measure for a light of that kind(?)
Title: Re: Tonemapping - Plz Halp
Post by: Designerman77 on 2020-04-22, 10:59:57
1. "Turn linear sRGB into digital camera product"

Quote
having it defaulting to a camera, with an option to switch to a very special mode, which will make your output less realistic, but compose-able in post.

You can get this by rendering your image at the default settings, then enabling LUT and picking one of the 3 Kim Amland's photographic LUTs. They are captured from real life digital cameras.
Then you can optionally reduce the strength of the LUT to ~0,8 (to your own taste) and play with highlight compression and filmic values (again to your own taste, to reduce highlight burn).


2. "I want to produce images like the masters"

Quote
This is a very attractive proposition and it speaks to the issue I am referring to. Regardless of whether such an implementation is feasible or not, I'd like to learn how to produce images that are of the quality we expect from the Corona Gallery and I just haven't seen strong tutorials - free or paid - demonstrating such an approach.

I am afraid this is not as easy as just following one or two tutorials. Artists have their own secrets. Some of them definitely use Photoshop or other post tools to adjust images in addition to what is done in the VFB, not only by changing the overall tone mapping/coloring, but also locally, e.g. by making some areas more or less noisy, brighter/darker, more clear/blurry, etc.




Hey Maru, what do you exactly mean by "rendering with default settings" ? Literally all cam settings untouched, like HC 1, contrast 1, etc ?
Absolutely no highlight compression mostly burns some whites, as we all know. I know that many guys fix this in post as 32 TIF bit or EXR.
In my workflow, for example, I rarely have time for this process... and honestly I don't even like the idea to fiddle around too much in post. Feels fake to me.

However, lately I notice that "correct tone mapping" gets more and more in Corona users´ minds... since, also in my opinion, it is THE key factor for realism.





Title: Re: Tonemapping - Plz Halp
Post by: Designerman77 on 2020-04-22, 11:11:08
Its not just tonemapping that makes those guys renders look amazing every time. Its attention to detail at every stage and questioning how something actually looks in reality vs what we imagine it looks like. Lacking some minute details is enough to make your brain subconciously question an images' realism so the answer to the question "How do i make it look like [insert artist here]" is usually "Hard work and practice". Personally, I think photorealism boils down to basically one rule.

I agree only partially with that. Of course stuff in your scene should be realistically modeled , textured, etc.

BUT: if your render engine just does not get that sweet spot of light calculation and the correct proportions in color grading, etc... even the most qualitative scene will look fake.

Lately I watched Johannes Lindqvist again. And as he mentions... the basic part of the realism in his work is due to FStorm and its visibly great tone mapping.
Quote Lindqvist: "even a stupid can generate realistic images in FStorm without tweaking on buttons."

And of course, as you mentioned: on top, his modeling and textures are 99% insane, which makes his images look insane.
As for post, I saw that he often does just a minimal tweaking... well, that´s clear with renders that are naturally tone mapped & lit from the start.



I will give another example: look at real photos. No matter how shitty, blurry or badly exposed they are, you will 99% see that it is a natural pic, not a render.
Why? because the proportions in contrasts, colors, etc. are "correct / natural.
Title: Re: Tonemapping - Plz Halp
Post by: lolec on 2020-04-23, 04:09:31
This subject has surfaced over and over since Fstorm seems to produce great results out of the box.  I wanted to try.
I found a good Cornell box taken with a Nikon D70, I believe it was used to showcase Maxwell 1.0 back in the day.

So, this is how it looks when we compare it to Corona default settings:

(https://i.imgur.com/jGMh5F1.jpg)

I agree that it looks a little dull and uninspiring. Maybe even "not realistic" compared to what you get from a camera.

Now, this is what you get with Fstorm in the Default settings.
(https://i.imgur.com/cdTz9nC.jpg)

I used the exact same RGB values, maybe there is something I don't know about Fstorm, so I tweaked the RGB values to match a little bit closer.

(https://i.imgur.com/xTisC9B.jpg)

That's better... so yea Conclusion: Fstorm produces more photographic images in the default settings.

However....

Look what happens when I enable LUT, choose Kim Amlan 02 and Enable Bloom and glare (it takes 1 second to do all of that)

(https://i.imgur.com/pWxduCa.jpg)

(https://i.imgur.com/kp9xQ5D.jpg)

Well, to me, that looks pretty photographic. I don't think it would be possible to correctly choose Fstorm or Corona in a blind test.

Now, if you like the original Fstorm look. Just increase Saturation to 0.2

(https://i.imgur.com/emB9ywa.jpg)

Now, I'm not suggesting that just because it is easy it shouldn't be extremely easy.

My proposal is to include a "Magic" button (just like the iphone has) that automatically enables the most photographic settings. Maybe even enables a new pannel with limited options that all produce "ready to use" images.

I do not think you will be able to produce Johanes level images just like that. But I do remember how much my images improved when I discovered LUTs, and how long it took, because I didn't have that information in my brain, there was some friction.

I would also say make the photographic LUT the default, since everyone who doesn't want LUTs, know what they are and how to disable them, but people who WANT LUTs, might not know they exist.

But that's probably too much of a change.

Anyway, hope this helps!
 

Title: Re: Tonemapping - Plz Halp
Post by: Nejc Kilar on 2020-04-23, 10:59:21
That is a very interesting observation and post Lolec. Thank you for your time :) I am a huge fan of those Dubcat's LUTs. They are amazing.

I suppose I'm wondering, could you share that Cornell box with us? I'd be really interesting in seeing how Octane handles it because they have a fairly specific "look" themselves.

Thanks again for your hard work, man!
Title: Re: Tonemapping - Plz Halp
Post by: Designerman77 on 2020-04-23, 14:48:50
Regarding Lolek´s test: me personally I know those parameters in Corona and what effects they have, including LUTs. Using them all day long.
I guess 99,5% of us know those tricks.
However, a simple box or a living room with all furniture, etc... still seem to be two different things. :)
Who knows, maybe if you make all shaders super-duper physically correct, according to real life, it might get an extra kick of realism... ???
But who's time for such?

This morning I tried to look at good 3D images that stand out ( like those fron J. Lindqvist, Ferretti, etc. ) and have to say that a lot of the realism happens in the way they deal with the light
in therms of highlight peak, contrasts, etc. Those great images mostly have like a color layer that influences all colors... vs. too clean colors. And no crazy contrasts... since actually real world looks like this.
That's actually a thing one learns as an artistic painter at academies in the first semester. :)
Title: Re: Tonemapping - Plz Halp
Post by: Designerman77 on 2020-04-23, 17:31:45
Right now I was a bit stuck on lighting a bathroom that has no windows and some creme colored wall tiles... not the nicest thing for the light mood.... I hate such rooms. :)

Long story short: by mistake I unticked "tone mapping" while the KimAmland LUT was full on ( value 1 )... and voilà, suddenly the freaking grayish light in the bathroom changed to a much more natural look,
just like I see now in Lolek´s posting.

Dudes... this setting which Maru mentioned (camera settings on default + Amland LUT)... seriously, this should be standard Corona setting and the first basic tutorial.
As other users mentioned: a pity to fiddle around for years in the cam settings, the light, materials, etc - just to realize that camera on more-less base setting plus a good LUT is the better way to go.

Glad that this topic of light mapping came up here!




Title: Re: Tonemapping - Plz Halp
Post by: Fluss on 2020-04-23, 17:46:46
It seems a lot of people believe there is a magic button that makes everything look photoreal but that won't happen. We're 90% there with Dubcat's LUTs. The only missing bit is a slightly better handling of highlights. That's it. Materials, composition and lighting play a huge part too. In fact, the main issue here is that with Dubcat's LUTs, you're stuck with embedded curves. So a good tone mapping tool would let access to toe, shoulder and medium parts of the image, in an elegant manner (probably in log space like ACES is doing during the display transform). But there is no universal settings... So I disagree to make those settings default.
Title: Re: Tonemapping - Plz Halp
Post by: lolec on 2020-04-23, 18:28:31
I agree there is no "magic" setting. But Fstorm has a strong LUT as default and maybe that gives people the idea of it being so much better (it is not)

I think this is a separate discussion. After you've done every possible thing, Fstorm still handles tonemapping a little better. But I suspect what most people would notice is just enabling a photographic LUT.

That's why I think a single button with an attractive name which selects a photographic LUT enables bloom and maybe some other small tweaks would make a huge difference and unlock peoples brains to start exploring with those settings too.

Title: Re: Tonemapping - Plz Halp
Post by: agentdark45 on 2020-04-23, 19:53:54
Thanks for taking the time to post up the Cornell box tests lolec.

While I agree that the Kim Amland LUT with minimal VFB fiddling produces a vastly super result than stock settings, the way Fstorm handles highlight peaks, the bottom curve of extreme darks and colours in general is still superior. It may not be as apparent in a simple Cornell box scene - start populating a real scene, with strong lighting certain areas and watch what happens to your highlights, strongly coloured materials and deep shadows; things start to break down and you end up chasing the dragon.

You can start to notice it in your Corona + Kim example 1; look at the exaggerated shadowing and black crush creeping in, as well as the front face of the small cube compared to the Fstorm tweaked example. Overall scene contrast is retained in the Fstorm tweaked example without exaggerated shadowing - it almost looks like light is behaving more realistically on the objects.
Title: Re: Tonemapping - Plz Halp
Post by: cjwidd on 2020-04-23, 20:48:35
@lolec that is a really compelling example, although I am reluctant to generalize too much from such a well-defined scene. That being said, the comparison does drive home your point about photographic LUTs.

Thank you for sharing!
Title: Re: Tonemapping - Plz Halp
Post by: Designerman77 on 2020-04-23, 23:04:00
Super important topic!
Maybe THE most important since long time. So thankful, all of you guys are participating with great input, ideas, opinions, etc.

I think many 3D artist would like to have a default setting that works like the human eye sees reality. Without lost details in highlight, nor with too blackish shadows, dull mid tones, etc.
And on top of this basic "eye-like" setting, more photo-typical behavior should be possible to - lets say - fade in with a slider. :))))

Of course, with enough grey cells, experience and try-and-error, one can always find a solution, also now.
But when clients demand great AND quick... well, then a render engine that simply does the magic out of the box would be the go to.

Today, for example, I lost hours with light setting... while a huge project has to be done as quickly as possible. And I know that my client will ask tomorrow for results.
So I'm sitting again now, at night and do work.
Costs nerves...

Title: Re: Tonemapping - Plz Halp
Post by: Fluss on 2020-04-24, 11:37:10
Well, that's more related to how you market your work, to be honest. Making great images takes time. So great and quick is a bit wacky.

IMHO the topic is not to mimic the perceptual representation of a scene but a filmic representation of a scene that is probably more contrasty than what you would think due to dynamic range limitations. Terminology is really important.

Not to mention that pro photographers never use their images as is, they retouch them to look good, convey emotions, emphasizing some aspects of the scene, tweaking colors, bringing more light in some places etc etc.... So having a reference curve to lookdev is totally fine but that stops there for me. Hence the fact that a lot of us were pushing for ACES as it offers both a nice filmic preview AND a color management system that will allow you to deliver your work on a variety of media including HDR displays. That said, that's a fixed embedded curve on which you have no control (if you use default OCIO workflow) so it may disappoint a lot of people.

Not to mention that such filmic curves compress highlights so much that you will have to increase energy levels of your scene which increase realism but will also have an impact on render times (more overblown areas). Unreal engine implementation fakes it by applying a 1.45 gain before the post-process because they did not want artists to be bothered by the exposure loss (was a bad choice imho).
Title: Re: Tonemapping - Plz Halp
Post by: Juraj on 2020-04-24, 13:44:36

Not to mention that such filmic curves compress highlights so much that you will have to increase energy levels of your scene which increase realism but will also have an impact on render times (more overblown areas). Unreal engine implementation fakes it by applying a 1.45 gain before the post-process because they did not want artists to be bothered by the exposure loss (was a bad choice imho).

This doesn't make sense. Exposure increase is identical to increasing light source intensity. One stop of Light is double the light (since one is exponential and other linear). That's not opinion, that's fact.
None of this affect render times negatively per se, that's the purpose of MSI to control.

These threads are just getting weirder and weirder.

(Great tests Lolec! btw).
Title: Re: Tonemapping - Plz Halp
Post by: mantaskava on 2020-04-24, 15:04:02

Not to mention that such filmic curves compress highlights so much that you will have to increase energy levels of your scene which increase realism but will also have an impact on render times (more overblown areas). Unreal engine implementation fakes it by applying a 1.45 gain before the post-process because they did not want artists to be bothered by the exposure loss (was a bad choice imho).

This doesn't make sense. Exposure increase is identical to increasing light source intensity. One stop of Light is double the light (since one is exponential and other linear). That's not opinion, that's fact.
None of this affect render times negatively per se, that's the purpose of MSI to control.

These threads are just getting weirder and weirder.

(Great tests Lolec! btw).

So here's a situation/scene - a single room with a single light in it. Now there's two ways to brighten it up, either you brighten your light or increase your EV/Exposure. Do I understand correctly that there's totally no difference which method you choose? Even if you would brighten your light to some crazy values (like 20 000 of whatever), it would still be okay? By okay I mean materials would still respond to light as expected etc.
Title: Re: Tonemapping - Plz Halp
Post by: Fluss on 2020-04-24, 15:46:21

This doesn't make sense. Exposure increase is identical to increasing light source intensity. One stop of Light is double the light (since one is exponential and other linear). That's not opinion, that's fact.


Did I said anything otherwise? What's the point here?

None of this affect render times negatively per se, that's the purpose of MSI to control.

Well, this may not apply to corona sampling method but definitely would with Vray bucket mode. Renderer has hard time sampling bright areas. Here are two renders with the exact same settings, just different display transform (so the linear render behind both images is exactly the same):

sRGB
(https://forum.corona-renderer.com/index.php?action=dlattach;topic=13398.0;attach=91266;image)

ACES
(https://forum.corona-renderer.com/index.php?action=dlattach;topic=13398.0;attach=91268;image)

If you wanna match ACES perceptual light intensities to the sRGB one, you'll have to increase the exposure. So the linear render will expose more overblown areas with which the renderer struggle to deal with. Of course we're not talking tremendous amounts but still may count in animations. That what I experienced in my tests.
But as I said earlier in this post, it may indeed not apply to corona as it is a different sampling method. Maybe I took a bit of a shortcut here, I admit. It still is not devoid of foundation. I'm pretty sure you did encounter that Juraj, as you were a Vray user. Remember the last bucket of death ?

source refering to the UE tonemapping gain : https://acescentral.com/t/creating-an-ocio-view-transform-to-match-default-unreal-4-aces-viewport-tonemapper/2437
                                                                  https://acescentral.com/t/acescg-for-animation-feature-and-further-questions/1545/21

"Keep in mind that Unreal Engine 4 ACES fitting applies a 1.45 gain, i.e., it is over-exposed compared to ACES reference implementation. This is an aesthetic choice done so that artists at Epic Games had an easier transition to ACES compared to a simple Gamma 2.2/sRGB OETF or a tonemapper keeping brightness in the ballpark."

So to conclude, ACES tonemapping allows you to bring more energy into your scene which makes quite a difference. But is it not the point of a tonemapper ?
Title: Re: Tonemapping - Plz Halp
Post by: cjwidd on 2020-04-25, 00:14:36
These threads are just getting weirder and weirder.

Hopefully you mean these *comments* are getting weirder and weirder - the thread is a pretty honest request for help on a diverse topic.

Those great images mostly have like a color layer that influences all colors... vs. too clean colors. And no crazy contrasts... since actually real world looks like this.

@Designerman77 can you elaborate on what is meant by "too clean colors"?

the way Fstorm handles highlight peaks, the bottom curve of extreme darks and colours in general is still superior.

F-storm always comes up as the comparison group on Corona threads when tonemapping is concerned, and what is described here^ is often the punchline of those conversations.

Is there really any disagreement about this, and if not, how is that reflected in the tonemapping rework that appears on the roadmap?
Title: Re: Tonemapping - Plz Halp
Post by: Fluss on 2020-04-25, 12:20:23
Well if you guys consider those comments weird then I'm gonna stop posting from now. I always try to add valuable insights and I always try to document my posts with links and tests, as much as possible. And I spend time for it as english is not my mother language. I also often mention that all the stuff I write is the reflect of my personal opinion and interpretation of things. I'm fine with contradiction as long as there is some argumentation to go with it. So I'm gonna stay far from those technical threads from now, I'm tired of this TBH.
Title: Re: Tonemapping - Plz Halp
Post by: cjwidd on 2020-04-25, 12:29:20
@Fluss I want to be clear that my comment was not targeting you and I appreciate you taking the time to share your insights on the forum +1
Title: Re: Tonemapping - Plz Halp
Post by: Jpjapers on 2020-04-26, 00:29:02
oh god this is going to turn into one of those threads isnt it haha
Title: Re: Tonemapping - Plz Halp
Post by: Designerman77 on 2020-04-26, 01:03:28
oh god this is going to turn into one of those threads isnt it haha

This discussion might one day catapult Corona into another level of realism.
Title: Re: Tonemapping - Plz Halp
Post by: cjwidd on 2020-04-26, 01:10:35
Yes, and perhaps more to the point, why aren't there more tutorials from accomplished (professional) artists on this topic - is because so much is left up to taste?

I would pay for a tutorial / walkthrough from Juraj just to study his process. @Jpjapers pointed me to Vizguru which has some good stuff, but it's funny how realtime art is basically drowning in tutorials - for every little workflow or technique you can imagine - but archviz, not so much.

Maybe I'm just not looking in the right places? Obviously Youtube has some tutorials, but it's mostly a toss-up.
Title: Re: Tonemapping - Plz Halp
Post by: Designerman77 on 2020-04-26, 01:13:22
These threads are just getting weirder and weirder.

Hopefully you mean these *comments* are getting weirder and weirder - the thread is a pretty honest request for help on a diverse topic.

Those great images mostly have like a color layer that influences all colors... vs. too clean colors. And no crazy contrasts... since actually real world looks like this.

@Designerman77 can you elaborate on what is meant by "too clean colors"?

the way Fstorm handles highlight peaks, the bottom curve of extreme darks and colours in general is still superior.

F-storm always comes up as the comparison group on Corona threads when tonemapping is concerned, and what is described here^ is often the punchline of those conversations.

Is there really any disagreement about this, and if not, how is that reflected in the tonemapping rework that appears on the roadmap?




I mean "raw" looking colors... you know, that unnatural, artificial look. :)
Title: Re: Tonemapping - Plz Halp
Post by: lolec on 2020-04-26, 02:32:01
I'm starting to believe that there are 2 simultaneous conversations happenings because there is a lot of overlap between the two, they look like a single conversation. I'm hoping this post would help see everything more clearly.

Last time I did some cornell box tests and some of you rightfully noted that it is not a sufficiently conclusive test as it is a simple setting with no dramatic light or materials. I decided to run a second test. My goal is NOT to say: Corona is as good or better than Fstorm, because I actually don't know.

My goal is to find out WHY people seem to think Fstorm is SO MUCH BETTER in terms of color management. And to find out if it is, maybe I should switch to Fstorm.

Disclaimer: I never used Fstorm before yesterday.

For that reason I set myself a few requirements:

1. The scene should be based in a Johannes L. Image, since that's what most people refer to when they say "Fstorm handles color better"
2. The least number of materials. Since I will have to replicate them in Fstorm and I'm a noob
3. Real World use. Something that a client would ask for.
4. Basic lighting

Ok, so I found this perfect scene by Johannes L. I set it up using just 4 materials. Corona Sun and Corona Sky. For Fstorm I used Fstorm Sun and Fstorm Sky. I left everything I could at default, only played with white balance to match colors on both engines.

Maybe it would be more "correct" to load the same HDR in both engines instead of using the stock SUN and SKY system. But I figured they are close enough, and an accurate representation of the available tools.


First, this is the image I'm trying to approximate:

(https://i.imgur.com/e7a6Xd9.jpg)


This is what I get out of both engines by default:

(https://i.imgur.com/PCiu9RV.jpg)

Ok, sure Fstorm is in fact producing a more pleasing and "photographic" by default. But you can see it is nowhere NEAR what Johannes makes.

Next is to enable everything I usually enable in Corona. This is my default workflow and the only thing I needed to tweak to come closer to the original image was a greater contrast value (usually 3 or 4, this time 7) 

(https://i.imgur.com/2VQSoap.jpg)

As I showed in my previous example, the image changes dramatically.

Here is a before and after:

(https://i.imgur.com/a5JDqJK.jpg)


Then I tried to match the Fstorm Default with as few settings as possible. To me, it looks like highlight compression plus contrast does a good job.


(https://i.imgur.com/CcSY2tq.jpg)

You can see how my workflow produces more "photographic" images than Fstorm default. I must say that I use these settings for 90% of my renders. And only tweak in specific cases. I usually do most of the project in my default settings and only tweak at the very end (Curves, contrast)

(https://i.imgur.com/p9RKdN4.jpg)


I wanted to see what would happen if I loaded Kim Amlan 02 LUT into Fstorm. I needed to tweak the "burn" value a little bit. I tried to move the least possible settings. I bet an experienced user would be able to get a better result, but this was very interesting to me.

(https://i.imgur.com/56GTfaQ.jpg)

Yes, of course, there are slight differences. Their SUN and SKY models are different, so maybe that's why colors are a little different. And the reflections don't match. I don't know how to properly use Fstorm materials so I did what I could. 

But after this experiment, I think it's clear that it would be very very difficult for anyone in a real-world scenario like this to say that Corona's tonemapping needs to be reworked from scratch because Fstorm produces incredibly more photographic images.

I simply don't believe that is true. I can tweak my contrast and color settings to make the images match a little better, but I wanted to see what a minimum workflow looks like, and if Fstorm is truly superior beyond a doubt.

I do believe that there is a very valid argument to be made about enabling LUT, highlight compression, and increasing contrast by default. Or make it a single button. Or in some way make it SUPER EASY to do, even by accident. My logic is that the pros would don't like it but know how and why to disable. And the rest of the world would enjoy much better images by default.

There is a different discussion, that only the top of the top of th professional users understand and really care about when you are pushing Corona to the limits you DO bump into the inherent limitations of the sRGB color space. But my guess is that 90 -95% of the time, when people complain about tonemapping, what ther are taliing about is what I'm showing in this experiment.

Another note. When a lot of people say something, even if you KNOW it is wrong, it is worth paying attention to. My guess is that because the experts know how to do what I'm showing intuitively and naturally, they dismiss conversations as nonesense. If there was only one or two people asking for "fstorm colors" then I would agree. But a LOT of people want that, maybe they don't know exactly what they want, but they want their images to look better.

So my hypothesis stands.

"fstorm colors" means 2 things.

1 is super complex, only a handful of people understand it and care about that. It requires a lot of work from the devs.

The other one is making certain settings, that are already there, more approachable, maybe the default.
Title: Re: Tonemapping - Plz Halp
Post by: agentdark45 on 2020-04-26, 05:46:34
Regarding the "colour" issue, I'm talking specifically about saturated colours breaking down in unrealistic ways under certain lighting conditions. There was an example above that shows the difference with what happens to reds and blues in ACES vs SRGB colour spaces as the exposure/lighting intensity changes. I have noticed this first hand in my scenes (yes even with the fabled Kim LUT) that sometimes a material that is properly created, without wacky RGB values will just not work as it should in real life and will need heavy post editing - I have yet to come across the same issue in FStorm.

While I appreciate your latest tests lolec, you would need to redo this with exactly the same materials (not quickly converted ones) and an HDRI capture of the exact same exterior lighting to draw any meaningful conclusions. We would also need to see a histogram of the images to compare what is going on in more details. When I talk of Coronas tone mapping limitations, which cannot be fixed by simply cranking the contrast slider (which crushes the hell out of blacks) + applying a LUT; I'm speaking specifically about the well known limitations of Reinhard tonmapping (burnt, saturated highlights or murky greys when clamped). The interplay between highlights, mids and the falloff to extreme black levels without getting crushed blacks gets completely ruined by cranking Corona's contrast slider.

Lets take a look at your last example, I will bullet point the major differences:

1.  The highlights are clearly overly clamped on the Corona version - most noticeably on the exterior/backplate, look at that ugly Reinhard burn and grey murkyness surrounding it. Now compare to the Fstorm version, notice how the highlights have a much more photographic burn and a realistic falloff to the green mids on the plant (which has kept its vibrancy and contrast, vs being washed out in a shade of grey). In fact you can see Corona struggling to tame the highlights of the exterior and plant from the very beginning (look at that neon green/yellow, and it doesn't get any better until it goes grey...sigh.)

2. Wood tones have not desaturated or lightened realistically in the presence of light/exposure in the Corona version. Perfect example of what I'm talking about when it comes to colour issues (along with the neon green plant highlights). I've had wood go vibrant overly contrasted red on certain parts of a scene, when the same material is almost desaturated in other parts of the scene (which it should have all been fairly desaturated) - usually in the presence of strong directional spotlights with a realistic Kelvin value. A good test of this is warm spot lighting in wooden shelves, with the same material elsewhere in the scene. Give it a go in Fstorm and Corona and marvel at the difference (again in a full scene). This colour phenomenon also happens sometimes to materials with a strongly coloured reflection (gold, copper e.t.c - and no, the RGB values were not sky high).

I will sum this up: you can not simply stick a LUT on a photo taken with a phone camera from 2010, adjust the contrast and claim it's as good as starting with the photo taken with the DSLR. You might get 90% of the way there, maybe fool a few people who think "it's good enough" but after extensive testing of both engines myself in many different types of scenes (yes even with dubcats ACES emulation settings, Kims LUTS e.t.c) I can hands down tell you they are not at parity tonemapping wise.
Title: Re: Tonemapping - Plz Halp
Post by: cjwidd on 2020-04-26, 07:02:38
@lolec Johannes has a Patreon page, Vizguru, where this scene can be downloaded for FStorm - is that where you obtained the scene file?

It sounded like you were recreating the scene from reference, but you could access the actual scene files from the Patreon page, if you are a member, of course.
Title: Re: Tonemapping - Plz Halp
Post by: cjwidd on 2020-04-26, 07:33:19
@agentdark45 just to be clear, the summary of your analysis is that Fstorm and Corona are not on parity in terms of tonemapping (?) and you are in disagreement with @lolec who is saying that, on balance, the tonemapping potential of both renderers, Corona and Fstorm, is basically comparable(?)

Title: Re: Tonemapping - Plz Halp
Post by: agentdark45 on 2020-04-26, 13:48:26
@agentdark45 just to be clear, the summary of your analysis is that Fstorm and Corona are not on parity in terms of tonemapping (?) and you are in disagreement with @lolec who is saying that, on balance, the tonemapping potential of both renderers, Corona and Fstorm, is basically comparable(?)

Correct. One more example to show how badly Reinhard stacks up compared to a proper filmic/ACES implementation:

(https://blenderartists.org/uploads/default/original/4X/4/0/4/404fce7a375dc725c79629c79debbc8e3d393f09.jpg)

Again, this cannot be done just by sticking a LUT over an image (i.e the band-aid approach).
Title: Re: Tonemapping - Plz Halp
Post by: Jpjapers on 2020-04-26, 14:20:37
TLDR: Its all about the filmic response curve and coronas currently isnt how it should be for proper filmic tonemapping. Fstorm has a more DSLR-like tonemapping system and so produces slightly more photographic looking renders.
Title: Re: Tonemapping - Plz Halp
Post by: Jpjapers on 2020-04-26, 14:22:30

This discussion might one day catapult Corona into another level of realism.

This issue has been discussed at length for the years on these forums in threads much much bigger than this as im sure agentdark remembers.

https://forum.corona-renderer.com/index.php?topic=14958.0
Title: Re: Tonemapping - Plz Halp
Post by: Designerman77 on 2020-04-26, 16:58:56
@Lolec, I guess all of us are very thankful for the work you have put into the tests!
Very cool, man!


@agentdark45: you, Sir have a brilliant eye and observation! The over clamping and grayish stuff behind that plant, as well as the tone of the wooden furniture, etc... exactly those are the things that also bug me in my renders. And I guess a lot of other users.
One could always say "aaah, that's only small differences". BUT our eye / brain instinctively notices exactly that stuff and realizes that it´s a fake pic.

As I superficially mentioned before: it´s all about the correct proportions of colors, contrasts, etc. that make images seem real.

Dudes, this discussion is by far the most awaited and defo my favorite one. I do believe that this is going to boost the quality of Corona in the next months, as the devs. brains surely start to work in the background. :)






Title: Re: Tonemapping - Plz Halp
Post by: Designerman77 on 2020-04-26, 17:02:29

This discussion might one day catapult Corona into another level of realism.

This issue has been discussed at length for the years on these forums in threads much much bigger than this as im sure agentdark remembers.

https://forum.corona-renderer.com/index.php?topic=14958.0


I remember that this topic is not new.
Well, then it is high time to not only discuss but start programming. :)
Title: Re: Tonemapping - Plz Halp
Post by: lolec on 2020-04-26, 20:05:44
No, my point is not that corona is as good at tonemapping. It is an objective truth that Fstorm uses a superior system. More realistic.

My point is that I have a feeling that when people, specially new users, complain about corona's tone mapping. What they are really talking about is that it is harder to get photographic images in corona, because the default settings are not meant to be photographic and the tweaks are not obvious.

That is why I think this topic comes up over and over and over. I believe there are two different subjects.

TRUE: Corona needs to move away from sRGB. It is the future, it is demonstrably better.

Also true: In order to notice the limits of sRGB you need to do some very extreme examples. In the day to day, most people would probably not hit that limit.

Maybe true: A lot of people, specially new users don't know the correct workflow and don't even get all of what Corona can offer. So they are comparing Corona default to Fstorm default. 

Fixing the first takes a lot of development  time apparently. but fixing the second might be easier.


Title: Re: Tonemapping - Plz Halp
Post by: Designerman77 on 2020-04-26, 23:36:08
No, my point is not that corona is as good at tonemapping. It is an objective truth that Fstorm uses a superior system. More realistic.

My point is that I have a feeling that when people, specially new users, complain about corona's tone mapping. What they are really talking about is that it is harder to get photographic images in corona, because the default settings are not meant to be photographic and the tweaks are not obvious.

That is why I think this topic comes up over and over and over. I believe there are two different subjects.

TRUE: Corona needs to move away from sRGB. It is the future, it is demonstrably better.

Also true: In order to notice the limits of sRGB you need to do some very extreme examples. In the day to day, most people would probably not hit that limit.

Maybe true: A lot of people, specially new users don't know the correct workflow and don't even get all of what Corona can offer. So they are comparing Corona default to Fstorm default. 

Fixing the first takes a lot of development  time apparently. but fixing the second might be easier.



Lolec, let´s be honest. Tweaking here, twisting there... all of us want colors & contrasts that look realistic as a starting point.
It is 2020... this should be the basic in any good render engine.



Title: Re: Tonemapping - Plz Halp
Post by: Fluss on 2020-04-27, 13:24:57
@agentdark45 just to be clear, the summary of your analysis is that Fstorm and Corona are not on parity in terms of tonemapping (?) and you are in disagreement with @lolec who is saying that, on balance, the tonemapping potential of both renderers, Corona and Fstorm, is basically comparable(?)

Correct. One more example to show how badly Reinhard stacks up compared to a proper filmic/ACES implementation:

(https://blenderartists.org/uploads/default/original/4X/4/0/4/404fce7a375dc725c79629c79debbc8e3d393f09.jpg)

Again, this cannot be done just by sticking a LUT over an image (i.e the band-aid approach).

The thing is, Reinhard is only compressing highlights. Filmic TM is compressing Highlights and applying a filmic curve to the render so that's a biased comparison. So basically, using dubcat LUT (the curve) and compressing the Highlights (Reinhard) already give pretty decent results. But, there is still that outdated sRGB EOTF in the process and that sucks. Other than that, the technical side of Corona is way more solid than Fstorm one from what I've seen.

But it's not all about Tonemapping, rendering space also have a significant impact. The wide gamut of ACEScg space offers quite a lot of extra colors that are beneficial to the render (colors are not compressed at the boundary of the gamut like in sRGB). Chris brejon made some interesting tests on that matter and you can clearly see it :

https://imgsli.com/MTQ2NzA

https://imgsli.com/MTQ2NzA/2/3

Corona is already using a wide gamut render space on which we do not know anything. How are handled the translations between sRGB and this space? Could totally be fine but i'd be curious to see how it compares to ACEScg one as we know the choice of the colorspace as a tremendous impact color saturation and can lead to bad results if not chosen carefully (otherwise everybody would be using XYZ as rendering space). All I know is that there is a reddish color cast on corona that is caused by that choice of colorspace(?).

edit : (?) mark on colorspace part
Title: Re: Tonemapping - Plz Halp
Post by: romullus on 2020-04-27, 14:08:47
Fluss, can you elaborate about "reddish colour cast"? I know about slight warm tint when using white Corona light with neutral WB, but i think it has nothing to do with colour space.
Title: Re: Tonemapping - Plz Halp
Post by: Fluss on 2020-04-27, 14:40:30
While making comparisons some time ago, I've noticed some sort of magenta shift in corona compared to Vray. That's subtle tho but it's there. Will try to find those and post them.

What is strange is I did not notice any color shift using ACEScg in Vray, but I did not look for it specifically so that's something I have to check.

Maybe it's not related to colorspace tho but I'd be curious to know where does it come from if I'm mistaken. Any hint about that?
Title: Re: Tonemapping - Plz Halp
Post by: romullus on 2020-04-27, 15:05:45
There were several discussions about that in the forum. You may want to read it in case you've missed it.

https://forum.corona-renderer.com/index.php?topic=19308.0
https://forum.corona-renderer.com/index.php?topic=20622.0
https://forum.corona-renderer.com/index.php?topic=27966.0
Title: Re: Tonemapping - Plz Halp
Post by: Jpjapers on 2020-04-27, 23:17:35
There were several discussions about that in the forum. You may want to read it in case you've missed it.

https://forum.corona-renderer.com/index.php?topic=19308.0
https://forum.corona-renderer.com/index.php?topic=20622.0
https://forum.corona-renderer.com/index.php?topic=27966.0

Im really surprised this is still a thing given its been reported for 3 years and is actually a fairly important thing that white is white.
Yeah 6500k could actually be closer to 6504 but if you set the same K in WB and light it should always be white no?


Title: Re: Tonemapping - Plz Halp
Post by: cjwidd on 2020-04-28, 00:17:19
@Jpjpapers You probably searched the links, but iirc the take home message is that there is some good internal reason why it is the way it is and it's best to set the light color directly if you mean to avoid the magenta tint(?)
Title: Re: Tonemapping - Plz Halp
Post by: Fluss on 2020-04-28, 10:13:28
Thanks for the links romullus. Btw, what makes you think this can't be related to colorspace? As far as I understand it, blackbody temperature just refers to a given RGB triplet in the rendering space. The shift could totally be occurring in the translation from wide RGB to sRGB. It also looks like the wide RGB colorspace has a D50 illuminant. This might also have its bite in the color shift. And just to avoid confusion and to prevent people from crying out 'scandal', I'm not a colorist.

That said, that's not a critical issue to me and I can totally understand that this stay as is, that's just curiosity.
Title: Re: Tonemapping - Plz Halp
Post by: romullus on 2020-04-28, 10:20:39
Btw, what makes you think this can't be related to colorspace?

Don't ask me :] All those talks about colour spaces etc. sounds like black magic to me. I'm happy to have enough brain power to somehow figure out linear workflow back in the days. I doubt i'll ever manage to handle all those fancy ace thingies you all talking about.
Title: Re: Tonemapping - Plz Halp
Post by: Jpjapers on 2020-04-28, 13:48:53
Im not saying it should change im just confused as to why regardless of what tint it is, if you have your WB and lighting kelvin the same,  why they wouldnt always be white?
Title: Re: Tonemapping - Plz Halp
Post by: Designerman77 on 2020-04-28, 13:50:25
Hey everyone,

as a byproduct of this discussion, I experimented a bit yesterday on the question "how is your raw render and how do you want it to look".

Conclusion: there ist not much escape from doing things in post at the moment.
However, simply saying "I want it to look good" will not do the trick. Instead, analyzing other (great) pics, an having a clear idea of what you want your pic to look like is a path one has to take.

Long story short, even after short and "minor" tweaks in PS, my images started to look more natural - with the side effect of losing that "dramatic" shadows, contrasts, color bleeding, etc.
But I have to admit that less artistic, dramatic & punchy looks "better", since it looks more natural.
The eye is not bombarded with crazy contrasts and colors - similarly to music recordings that do not violate your ears with artificially cranked up frequencies.

What I also noticed years ago: if you are not satisfied with color grading, etc., desaturate the pic to BW and tweak the adjusters ( highlights, contrast, blacks, etc. etc. ) until your eye is pleased.
When returning the saturation-slider back to default, the pic will - in most cases - look way better also in color.
I got this idea from the observation that well lit & color graded pictures somehow always look good, no matter how much you darken your screen, or desaturate them, how blurry a pic is, etc.
Title: Re: Tonemapping - Plz Halp
Post by: lupaz on 2020-04-28, 16:03:33
These two comments, in my opinion, summarize the issue pretty well.
But -and I'm far from an expert in raytracing- can we discard that the realism in Fstorm vs Corona comes from sampling and raytracing?


1.  The highlights are clearly overly clamped on the Corona version - most noticeably on the exterior/backplate, look at that ugly Reinhard burn and grey murkyness surrounding it. Now compare to the Fstorm version, notice how the highlights have a much more photographic burn and a realistic falloff to the green mids on the plant (which has kept its vibrancy and contrast, vs being washed out in a shade of grey). In fact you can see Corona struggling to tame the highlights of the exterior and plant from the very beginning (look at that neon green/yellow, and it doesn't get any better until it goes grey...sigh.)

2. Wood tones have not desaturated or lightened realistically in the presence of light/exposure in the Corona version. Perfect example of what I'm talking about when it comes to colour issues (along with the neon green plant highlights). I've had wood go vibrant overly contrasted red on certain parts of a scene, when the same material is almost desaturated in other parts of the scene (which it should have all been fairly desaturated) - usually in the presence of strong directional spotlights with a realistic Kelvin value. A good test of this is warm spot lighting in wooden shelves, with the same material elsewhere in the scene. Give it a go in Fstorm and Corona and marvel at the difference (again in a full scene). This colour phenomenon also happens sometimes to materials with a strongly coloured reflection (gold, copper e.t.c - and no, the RGB values were not sky high).

I will sum this up: you can not simply stick a LUT on a photo taken with a phone camera from 2010, adjust the contrast and claim it's as good as starting with the photo taken with the DSLR. You might get 90% of the way there, maybe fool a few people who think "it's good enough" but after extensive testing of both engines myself in many different types of scenes (yes even with dubcats ACES emulation settings, Kims LUTS e.t.c) I can hands down tell you they are not at parity tonemapping wise.

My point is that I have a feeling that when people, specially new users, complain about corona's tone mapping. What they are really talking about is that it is harder to get photographic images in corona, because the default settings are not meant to be photographic and the tweaks are not obvious.

That is why I think this topic comes up over and over and over. I believe there are two different subjects.

TRUE: Corona needs to move away from sRGB. It is the future, it is demonstrably better.
Title: Re: Tonemapping - Plz Halp
Post by: Juraj on 2020-04-28, 19:05:36
I would pay for a tutorial / walkthrough from Juraj just to study his process.

:-) No need to pay me, I posted my approach almost every year, every time someone asked. It's true I didn't make a concise tutorial out of it, but that's because (and this answers why there in general aren't many tutorials on topic) it's not easy to concentrate and doing this properly. Some people open Twitch and ramble random stuff for 40 minutes and others, like me, struggle to make good script and follow that. I rather not produce anything that produce something that's mediocre. My CGArchitect article took me week to write..and I don't want to spend so much of my free time to CGI.

Disclaimer: I also absolutely want both: color management (OCIO/ACES is great) and better tonemapping (ACES Filmic curve is great). I've requested these years ago. I will be super happy once we eventually get them. And we will, I've never seen any devs more receptive that Corona guys.

But.. these things aren't as radical as some people might hope for. Out of fun I googled ACES Filmic curve and google shows on first image page an experiment I did with Dubcat in 2017. He took my scene to Fusion (pure linear 32bit output) and applied ACES Filmic curve (with final sRGB output, sRGB is color space only btw, it has nothing to do with tonemapping whatsover). The other image is Corona HC8 (I guess was chosen to maximize highlights compression) plus a simple S-Curve that mainly focuses on boosting midtones (the midtones look bit more shitty because the curve was applied to clamped image in Photoshop... Corona didn't have curves in VFB yet)
The results are fairly similar. Of course, the scene lacks strong colors where the saturation would fall apart, but even this can be easily fixed in interim by using Vibrance to adjust saturation levels.

This is currently not reproducible in Framebuffer with LUT because it would requite exact translation to LOG first and applied right after in that order { Linear --> LOG ----> LUT }

I said these threads are getting weirder because there is odd militancy in responses. Lot of strange stuff is taken as fact, it's becoming quite haven for misinformation.

But for you out of interest: My current settings are sub <2 HC, Midtones boosting curve (with peak more towards highlight to avoid flatness) without toe as I like to adjust black with Contrast, which is 4-5. Then..still comes a lot of selective post-production, but this identical to my photography from that point, creative changes, not fixes. So, luminance masks, vibrance adjustment, micro-contrast enhancement, painting glares on (I don't like the current bloom&glare much and I want to boost this artificially).

Last: Great posts from Lolec!

(https://forum.corona-renderer.com/index.php?action=dlattach;topic=28156.0;attach=125068;image)

(https://forum.corona-renderer.com/index.php?action=dlattach;topic=28156.0;attach=125070;image)
Title: Re: Tonemapping - Plz Halp
Post by: cjwidd on 2020-04-28, 20:11:12
What I also noticed years ago: if you are not satisfied with color grading, etc., desaturate the pic to BW and tweak the adjusters ( highlights, contrast, blacks, etc. etc. ) until your eye is pleased.
When returning the saturation-slider back to default, the pic will - in most cases - look way better also in color.

That's an interesting trick, I'll have to try that sometime - thanks for sharing!
Title: Re: Tonemapping - Plz Halp
Post by: cjwidd on 2020-04-28, 20:17:18
Some people open Twitch and ramble random stuff for 40 minutes[...]

I wouldn't be opposed to listening to you ramble for 40min *about your work* - open a project and just walkthrough what you did and why - that would be very informative for someone like me and presumably others. Of course, this is basically what Johannes Lindqvist does on his Patreon and it has been very well received. If you don't have time because of work or other reasons, well, I understand that too.

I've seen / read many of the write-ups that you've shared to the forums, including the ACES experiments posted above - they were very interesting!
Title: Re: Tonemapping - Plz Halp
Post by: Jpjapers on 2020-04-28, 22:30:31
I agree with Juraj. Theres alot of misinformation and lots of language around colour spaces gets used interchangeably or incorrectly and it just clouds the waters and makes it difficult to find the right information.

I think it would be nice for a 'once source of the truth' approach eventually. Perhaps if a proper filmic approach turns up in corona in the future there might be a nice little video explaining it all with examples of why its (evidently) a better approach for the way people use renderers to clear up the cloud of rambly threads that this kind of discussion always manages to turn into.

(https://i.imgflip.com/3yk9wu.jpg)
Title: Re: Tonemapping - Plz Halp
Post by: Juraj on 2020-04-28, 22:37:46
A Trump meme already 😀Boy this escalated quickly.
Title: Re: Tonemapping - Plz Halp
Post by: cjwidd on 2020-04-28, 22:59:10
Isn't there something futile about discussing color management at all with respect to Corona Renderer for 3ds Max? As I understand it, Max is not a color managed workspace, and if it's taken Autodesk like 7 years just to add a new spinner to the chamfer modifier, why should we even begin to expect that color management is going to appear(?)
Title: Re: Tonemapping - Plz Halp
Post by: Juraj on 2020-04-28, 23:22:37
Waiting for Autodesk might indeed be futile but renderer can supply lot of native features like Corona shows 🙂
As long as its the main rendering engine you use it can even be better integrated solution (selection in framebuffer, etc.).

Vray already went this path so it makes sense Corona will opt so too.
Title: Re: Tonemapping - Plz Halp
Post by: Jpjapers on 2020-04-29, 00:20:44
A Trump meme already 😀Boy this escalated quickly.

Points for guessing the kelvin of his face.
Title: Re: Tonemapping - Plz Halp
Post by: niljut on 2020-04-29, 08:36:37
Isn't there something futile about discussing color management at all with respect to Corona Renderer for 3ds Max? As I understand it, Max is not a color managed workspace, and if it's taken Autodesk like 7 years just to add a new spinner to the chamfer modifier, why should we even begin to expect that color management is going to appear(?)

https://makeanything.autodesk.com/3DSMAX/public-roadmap-25B1-201DB.html#rendering-future

It is definitely on their minds at least.
Title: Re: Tonemapping - Plz Halp
Post by: cjwidd on 2020-04-29, 09:21:43
oh wow, thanks for sharing that^ I had no idea they were even thinking about it
Title: Re: Tonemapping - Plz Halp
Post by: Fluss on 2020-04-29, 09:23:53
Isn't there something futile about discussing color management at all with respect to Corona Renderer for 3ds Max? As I understand it, Max is not a color managed workspace, and if it's taken Autodesk like 7 years just to add a new spinner to the chamfer modifier, why should we even begin to expect that color management is going to appear(?)

https://makeanything.autodesk.com/3DSMAX/public-roadmap-25B1-201DB.html#rendering-future

It is definitely on their minds at least.

Well it was added 3years ago so wouldn't capitalize on this 😁: https://forums.autodesk.com/t5/3ds-max-ideas/opencolorio-ocio-support/idi-p/7028915
Title: Re: Tonemapping - Plz Halp
Post by: Fluss on 2020-04-29, 09:55:06
Also, for those who missed it, you really should read Chris brejon online book: https://chrisbrejon.com/cg-cinematography/

He is a lighting artist and he worked in some of the biggest studios. There is a whole chapter about ACES and a lot more useful tips. Check it out!
Title: Re: Tonemapping - Plz Halp
Post by: cjwidd on 2020-04-29, 10:05:58
yeah this is a great [FREE] resource, I've had it bookmarked for some time now :/
Title: Re: Tonemapping - Plz Halp
Post by: Fluss on 2020-04-29, 10:38:25
did you check it from time to time? he is adding new stuff, recently in the ACES chapter
Title: Re: Tonemapping - Plz Halp
Post by: Juraj on 2020-04-29, 10:49:51
Holy shit that resource has become serious wiki-bible. Now it's even more daunting :- D

Seriously if I were to start with CGI today, and came across this I would immediately find other career.
I need to bite into it.

The first section is just mind-boggling. The whole CGI community spent 10 years deciding on question of "What can change the nature of gamma?" and this guy just outlines the whole matrix.
Title: Re: Tonemapping - Plz Halp
Post by: cjwidd on 2020-04-29, 10:57:22
Seriously if I were to start with CGI today, and came across this I would immediately find other career.

lmao

did you check it from time to time? he is adding new stuff, recently in the ACES chapter

Nah, I haven't checked it since it was first recommended to me some time ago - it was already very thorough then. I'll have to see what chapters have been updated.

Title: Re: Tonemapping - Plz Halp
Post by: Fluss on 2020-04-29, 12:08:48
Holy shit that resource has become serious wiki-bible. Now it's even more daunting :- D

Seriously if I were to start with CGI today, and came across this I would immediately find other career.
I need to bite into it.

The first section is just mind-boggling. The whole CGI community spent 10 years deciding on question of "What can change the nature of gamma?" and this guy just outlines the whole matrix.

hehe, if I came across this at the beginning, I'd be a way better artist today!
Title: Re: Tonemapping - Plz Halp
Post by: cjwidd on 2020-04-30, 08:18:04
When I first posted this thread I was a little concerned there would be some self-righteous indignation about how I was basically asking for a magic button to cure my bad images or something like that. Of course, that was not what I was asking, but I was - more or less - implying that a significant proportion of what constitutes a good image is tonemapping (or lighting).

I recently subscribed to Johannes Lindqvist's Patreon to get a behind the scenes look at his approach to archviz / image creation, and he shared an anecdote in response to a Corona forum thread that *WAS* asking for a magic trick (based on Betrand Benoit's Varenna project).

He said,

Quote
If you take a photo in really bad lighting, the image looks photo realisitic. It may look like shit, but still realistic. It doesn’t matter what lighting circumstances you take your photo in, it still look realistic, since it’s obviously a real photograph. And the same principle actually applies to 3D as well, even if you have bad, ugly lighting, that alone is not the reason to why your image doesn’t look realistic.

I guess I did not have the common sense or clarity of mind to arrive at this really obvious truth before reading it, but it really struck me.
Title: Re: Tonemapping - Plz Halp
Post by: Fluss on 2020-04-30, 10:14:36
While I totally agree with what Johaness said about real photography, I'm also a bit disappointed by the CGI part. That statement is true when everything is done right, not only tone mapping. There are a lot of phenomena hidden behind the hood. Caustics, light polarization, diffraction etc etc, to name a very few. The thing is while we are calling render engines unbiased, we're still faking it or mimicking it. Tonemapping really is important but with the wrong shaders, wrong light energy, not enough details, perfect surfaces, it won't look realistic at all. That's a balance between a whole load of stuff. A good tone mapping is crucial for achieving photorealism, so as the rest. So yes we need it but it won't revolutionize the whole industry like some people seems to say.

If you compare a sony and a fuji camera output, pictures do not look the same. Colors are different, tone mapping is different but it still looks realistic. Simply because you capture the right scene-referred data (Everything is behaving as it should, how we use to see it). So if you don't feed the rendrer with the right data, the tone mapping curve won't make it look good.

So photorealism really isn't that simple to define as there is a whole lot of intricacies. The key is to use references and observe the world around you. I often look at light interactions around me and a lot of these observations are making me think "If I'd see this in one of my renders, i'd probably think this is a bug".

It would be really interesting to make a thread with great images and review them to highlight why it works well.

Also, what's make Fstorm appealing on the first sight, to me at least, is that the tone mapping curve is not driven by the LUT so you can use the LUT slot for other purposes. If you look at Johaness workflow, he is using LUTs to stylize his renders (desaturate colors, shifting black etc etc..)
Title: Re: Tonemapping - Plz Halp
Post by: Juraj on 2020-04-30, 10:39:45
Quote from: Fluss
That statement is true when everything is done right, not only tone mapping. There are a lot of phenomena hidden behind the hood. Caustics, light polarization, diffraction etc etc, to name a very few.

Hah I started writing response before you and then you write 90perc. of what I wanted ! Absolutely agree with the above.


I would argue that "ugly" lighting in CGI is easier to pull of photorealism, best example being flesh light. High contrast, small & directional, creating super strong highlights, placing focus on shapes instead of surfaces.
And vice versa, high-end studio photography sets look very CGI like, similarly like retouched people look almost plastic.

This is where I would caution against jumping to conclusion there is something this has to do with "tonemapping" necessarily. Your cell-phone is not doing any advanced tonemapping that wood look better than Reinhard. Every digital sensor captures data linearly, those linear data when extracted in that way look exactly like Corona with everything at 0 (and HC=1). Yet it looks photoreal because of the amount of detail.

The opposite is also true to some degree, that very good tonemapping & grading can make simple & lazy CGI set look photoreal...but only in low-res and only for a moment.

So both of those aspects are important, something Lolec and few others brought out. It can't be tied to tonemapping.

Also...the mythical "DSLR-like" tonemapping. It's not imho what people think it is. What your camera does, it only applies gamma curve onto linear data, then raw convertor applies S-Curve (either its own, or the one described in raw file, which is usually based on JPEG post-production by camera maker) and their own bit of tonemapping which you have available in the settings on front page of ACR for example. At that point, camera hasn't done anything, the Sony sensor (whether sold to you by Sony, Nikkon, Fuji, etc..) has only provided linear data. No tonemapping whatsoever. They do attach associated s-curve into the file (which the raw converter only interprets! the curve is only identical if you save directly to jpeg from camera).

So if we want "DSLR-like" tonemapping, there would have to be way to use any raw converter tools. But there's a catch, they don't expect the amount of information provided by CGI. Raw formats are barely 16bit at best, already with gamma curve.
If you force-open 32bit file in Adobe Camera Raw, it will do random equilizing, which can look almost bizzare depending on dynamic range of your scene. This is the only "magic" it does to photos as well... but the algorithm obviously gets very confused by the kind of data it gets with rendering.
You can do the old trick of zero-ing everything in older process setting, then you can use the default state of rendering and only apply tonemapping that AdobeCameraRaw offers. It only affects highlights.

Quote from: Fluss
So photorealism really isn't that simple to define as there is a whole lot of intricacies.

Yeah, very much this.

There is interesting research done by Paul Devebec & Co (or John Hable? I am not sure, I came across it on FilmicWorlds which is his blog) where ultra-realistic models (like the most high-end Hollywood VFX stuff we can do) still looked wrong to our eyes. Then they flipped them above to fool our brain finally. The evolutionary amount of sensory recognition is so well trained, that we perceive almost minutae differences between real humans and CGI humans. Even if we are talking super rendered, super lit, super post-produced photo-scans with perfectly shaped-in emotion.

I believe this effect manifests to much higher degree in architecture as well as we would like to admit. After all, how much time humans spend inside some kind of architecture? Same with nature. It always looks somewhat wrong. Opposed example would be cars, recent innovation, rather simple in shapes. I think almost nobody can tell difference between CGI or real car... even not exactly great renderings.

Every time people congratulate something for looking very photorealistic in forum, there is some crutch that strongly helps it. Super massive DOF, odd angle focusing on detail, etc. Lot of time these projects have 4-5 very "real" looking images...until the last one, with flat lighting, wide angle showing the whole room that client actually requested. And it doesn't look real at all. With no hack to help it, the same grading & tonemapping suddenly doesn't help at all.

Can most artists be sure when the issue can be down to tonemapping & grading, and when it's the detail? I would say this ratio is lot different than people think.

Title: Re: Tonemapping - Plz Halp
Post by: cjwidd on 2020-04-30, 11:55:54
[...] best example being flesh flash light.

*edited for general audiences 😄

👀
Title: Re: Tonemapping - Plz Halp
Post by: romullus on 2020-04-30, 12:03:14
LOL
Title: Re: Tonemapping - Plz Halp
Post by: cjwidd on 2020-04-30, 12:05:01
@JurajTalcik Are you referring to this (http://filmicworlds.com/blog/the-uncanny-valley-as-ffa-rejection/) article about the uncanny valley?
Title: Re: Tonemapping - Plz Halp
Post by: Juraj on 2020-04-30, 12:37:53
False security of grammar checker 😀
Title: Re: Tonemapping - Plz Halp
Post by: Fluss on 2020-04-30, 17:12:07
Also, what's make Fstorm appealing on the first sight, to me at least, is that the tone mapping curve is not driven by the LUT so you can use the LUT slot for other purposes. If you look at Johaness workflow, he is using LUTs to stylize his renders (desaturate colors, shifting black etc etc..)

Just wanna add that I know curves are there but I find them uber-sensitive and it's impossible to fine-tune, I never use them.
Title: Re: Tonemapping - Plz Halp
Post by: lupaz on 2020-04-30, 17:40:52
Guys, I really think that the evidence is clear: Renderings done with Corona are more easily recognizable as CGI than those made with Fstorm.

Really, tonemapping is not IT. Even if the Corona team re-works the tonemapping area, it may get better, but it's not it.

I was just at the Facebook pages of Fstorm and Corona.

It took me a while to find images in the Fstorm group, even by what it seemed the most inexperienced memebers, that didn't look like a photo.
Then I went to the Corona Facebook page. The fist image I found was obviously a rendering done by a not-so-experienced user and there was no way to tell my brain that it may be a photo.

See images below. I tried to take the worst images in the Facebook pages. I think the evidence is obvious: It's easier to make photorealism with Fstorm than with Corona. And I cannot believe that the discussion is about improving tonemapping to get the photorealism that you get with Fstorm by default. (Very clear to me with the image of the laundry room, made with Fstorm. It looks like a toy, but there's a realistic quality to it, with seemingly no effort)

It's like when we were having this conversation in the Vray forum just when Corona was released back in 2013 or so. The issue is not tonemapping.
IMO the issue has to do with the level of bias-ness: Both Fstorm and Corona are biased render engines. But the way Corona does the bias by default is not as good as what Fstorm does.

(https://i.imgur.com/OokXvmT.jpg)
(https://i.imgur.com/pR9fsSk.jpg)
(https://i.imgur.com/eCYZvJ8.jpg)
(https://i.imgur.com/dpzipoM.jpg)
(https://i.imgur.com/nhUVT3O.jpg)


Even in this image, obviously with a lot of detail, I can tell that boat is fake.
(https://i.imgur.com/GMXygbD.jpg)


Title: Re: Tonemapping - Plz Halp
Post by: Fluss on 2020-04-30, 17:46:14
I don't know if image compression ruin all of these but to be honest, the last render looks the best of all of those to my eye
Title: Re: Tonemapping - Plz Halp
Post by: lupaz on 2020-04-30, 17:48:28
I don't know if image compression ruin all of these but to be honest, the last render looks the best of all of those to my eye

Yes, I added that render there to show that even an excellent work with a lot of detail, in Corona, still doesn't look like a photo.
Title: Re: Tonemapping - Plz Halp
Post by: lupaz on 2020-04-30, 17:54:01
Even on this image: Very simple scene by what it seems to be a not very experienced artist:
Except for the window, my brain may believe this is a photo.

(https://i.imgur.com/OH02OB2.jpg)
Title: Re: Tonemapping - Plz Halp
Post by: Juraj on 2020-04-30, 18:04:20
Since I never tested fstorm I cant tell what causes this but I noriced this on Bertrands scene he sell. The Fstorm has much stronger direct light. Why is it? Clamped GI? Is it accidental or intentional. It gives the space more readable light in way that I doubt is due to tonemapping.

Someone would have to do a deep dive becayse the features have odd parity in behavior. Fstorm HDRI has two modes (weird option to cut off direct light?), their portal light effectively becomes new area light (like one option in Vray).

Very hard to pick out what exactly is the cause with so many variables.

With Dubcat, we suspected the shader. I wonder if something lije OrenNayar wouldnt cause more highlights from durect light?
Title: Re: Tonemapping - Plz Halp
Post by: Fluss on 2020-04-30, 19:04:54
There you are, the effect on this one is more what we are referring to when talking about Fstorm TM. I wouldn't even call this image realistic, there is a bunch of stuff that are off but there is something in it that feels natural indeed.
Title: Re: Tonemapping - Plz Halp
Post by: romullus on 2020-04-30, 19:25:32
Those comparisons are meaningless when viewer is even more biased than renderer...
Title: Re: Tonemapping - Plz Halp
Post by: agentdark45 on 2020-04-30, 19:39:01
There you are, the effect on this one is more what we are referring to when talking about Fstorm TM. I wouldn't even call this image realistic, there is a bunch of stuff that are off but there is something in it that feels natural indeed.

The Fstorm TM tonemapping magic imo is mostly to do with the way it handles highlights/burnouts, the falloff to extreme blacks (and colour behaviour in general) and the ability to produce a nicely contrasted image without sacrificing the previously mentioned elements. The Corona VFB crushes the hell out highlights/blacks when trying to achieve a contrasty photographic image, either via a combo of stock HC/contrast/LUTs (see the previous comparison examples by lolec and my detailed observation notes). The way Fstorm clamps highlights and the gentle roll off to true black is beautiful, it isn't in Corona, period.

Again, I cannot stress enough that the handling of highlights and blacks cannot simply be fixed by arbitrary curves/LUTs inside of Corona's VFB - sure we might be able to get close (read: 90% as close) by rendering out a linear 32bit image and fooling around in photoshop - but goddamn, what a painful workaround.

I'm also starting to think part of the Fstorm magic is the internal colourspace, take a look at the examples on Chris Brejon's ACES page (at the very bottom and click left and right): https://chrisbrejon.com/cg-cinematography/chapter-1-5-academy-color-encoding-system-aces/ - notice that even GI gets affected along with colour bounce, most apparent in the red ball.

Again I should stress that I am nitpicking here, Corona has decent tonemapping options but when compared to FStorm it simply isn't on the same level after using both engines extensively. Sure, I can produce nice images in Corona (and I do for all interior work), but if I wasn't as limited with Fstorms materials + VRAM I would use Fstorm everytime. For high end product shots I use Fstorm exclusively - I have tried to match a lot of my scenes 1:1 in Corona and something is always off in comparison (overly clamped highlights/highlights too burned/colours being weird unless manual silly tweaking/blacks being crushed when trying to achieve more contrast...the list goes on).

Title: Re: Tonemapping - Plz Halp
Post by: lupaz on 2020-04-30, 19:49:14
Those comparisons are meaningless when viewer is even more biased than renderer...

Not sure what that means.


For further comparison some images below.

Could DOF have something to do with it?
The hotspots in Fstorm are very good. ACES?

This is the what Vlado says about biased and unbiased rendering https://www.chaosgroup.com/blog/the-truth-about-unbiased-rendering (https://www.chaosgroup.com/blog/the-truth-about-unbiased-rendering)
I believe that how Corona and Fstorm choose to be unbiased is what ultimately makes the difference in realism.

CORONA:
(https://i.imgur.com/HpQRepH.jpg)
(https://i.imgur.com/NiUy0YI.jpg)
(https://i.imgur.com/L16sbSz.jpg)
(https://i.imgur.com/92ZaDTK.jpg)
(https://i.imgur.com/YNvbHEG.jpg)


FSTORM:

(https://i.imgur.com/WI62fjg.jpg)
(https://i.imgur.com/cqjxrSW.jpg)
(https://i.imgur.com/taBSPNH.jpg)
(https://i.imgur.com/jkXSF4u.jpg)









Title: Re: Tonemapping - Plz Halp
Post by: cjwidd on 2020-04-30, 21:06:02
I really did not create this thread with the intention of comparing FStorm and Corona Renderer...
Title: Re: Tonemapping - Plz Halp
Post by: agentdark45 on 2020-05-01, 17:08:01
I really did not create this thread with the intention of comparing FStorm and Corona Renderer...

I think people are making the comparison because Fstorm has the best tonemapping algorithm out of all common rendering engines at the moment.
Title: Re: Tonemapping - Plz Halp
Post by: Fluss on 2020-05-01, 17:57:32
I really did not create this thread with the intention of comparing FStorm and Corona Renderer...

I think people are making the comparison because Fstorm has the best tonemapping algorithm out of all common rendering engines at the moment.

The thing is, as Juraj pointed out, we're not even sure the "Fstorm look" can be attributed to tone mapping only. So further investigations need to be conducted before making such a claim.
Title: Re: Tonemapping - Plz Halp
Post by: cjwidd on 2020-05-01, 21:02:09
Well, regardless of the comparisons, there are a lot of interesting comments about *tonemapping* that are emerging from those comparisons, so that's good 👍
Title: Re: Tonemapping - Plz Halp
Post by: agentdark45 on 2020-05-01, 22:11:29
I really did not create this thread with the intention of comparing FStorm and Corona Renderer...

I think people are making the comparison because Fstorm has the best tonemapping algorithm out of all common rendering engines at the moment.

The thing is, as Juraj pointed out, we're not even sure the "Fstorm look" can be attributed to tone mapping only. So further investigations need to be conducted before making such a claim.

Maybe not attributed solely to tonemapping, but I would hazard a guess it's at least 50% of the reason. Please look at the highlights and roll-off to extreme black in the examples posted earlier by lolec - that is one aspect that is definitely down to tone mapping. Colour behaviour differences could be due to the internal colour space/custom matrix, I agree.

I would urge anyone who has doubts about the highlight/black crush issue to test it for themselves in 1:1 comparisons as Fstorm is fully functional (with watermarks). You will not get the same level of pop/photographic contrast in Corona (without external post processing), without sacrificing either blacks or highlights - I would almost liken this to differing dynamic ranges of cameras as an IRL analogy.
Title: Re: Tonemapping - Plz Halp
Post by: lolec on 2020-05-02, 00:47:05
There is no way 50% of the realism coming from the Fstorm community is because of the tone mapping. Install Fstorm and try it. See if your images look 50% more realistic just like that. They won't.

My guess based on the actual tests I did and trying to figure out the Fstorm phenomenon: 

1. It is easier to get a baseline good result because of the default settings, easier to take that to photoshop than what corona gives as default. Less settings to fiddle with, less to learn in order to get a good result (Great and excellent results are just as hard IMHO)
Other than the LUT default examples I provided earlier, here is another one for bokeh:
(https://i.imgur.com/qKLWf0I.jpg)

You can argue it is stupidly simple to just move center bias to 0.5 instead of 0. But it is SIMPLER to do nothing.

2. Thanks to gaming, people already have powerful GPUs installed, so while a 7k USD PC might provide little speed distinction between a threadripper build vs multiple 2080Ti build, new artists are more likely to already own the right hardware to take advantage from Fstorm, thus learning it faster. In the early days of learning, when the curve is steeper, 50% faster results means you are learning and iterating twice as fast. My theory is that you can become GOOD much faster with Fstrom with the hardware you already own. 

3. Totally subjective based on MY experience and appreciation, but settings seem to be "dumbed down" example: White balance is based on rgb, so you are forced to tweak by feel instead of by Kelvin value. This promotes visceral interaction instead of technical interaction, which I believe attracts artists wich tend to work by feel more than by scientific technique.



PS. I want to make absolutely clear that I DO believe tonemapping should be reworked. I Know reworking tonemapping would help get better images, that is just the truth, my vote for most wanted feature is set to that and I'm sad we don't have it yet. Bokeh is actually one of the areas you would notice the change, as overblown highlights would look white in Fstorm and Solid Color in Corona, as it was discussed in my thread in 2018:
https://forum.corona-renderer.com/index.php?topic=22219.msg136777#msg136777

But the fact that so many people think that so much of Fstorm's realism is because of tonemapping, does not make sense. The fact that you estimate that Fstorm is more realistic 50% thanks to tonemapping is evidence of that.

We''ve had Ultra realistic renders for decades, even without all of the technologies we have today on materials, ray tracing and tonemapping. New tools just make it easier.

TLDR: I would like Corona to rework tonemapping to achieve what it is now IMPOSSIBLE to do in corona, but there is a lot they can do to make what is already possible much accessible. I think that would clear much of the misconception that Fstorm is so much better at "realism"
Title: Re: Tonemapping - Plz Halp
Post by: cjwidd on 2020-05-02, 01:50:00
I'm not sure it's a meaningful or empirical question to ask what percentage of an image is attributable to tonemapping - or shaders, lighting, modeling, etc.
Title: Re: Tonemapping - Plz Halp
Post by: agentdark45 on 2020-05-02, 03:42:37
There is no way 50% of the realism coming from the Fstorm community is because of the tone mapping. Install Fstorm and try it. See if your images look 50% more realistic just like that. They won't.

But the fact that so many people think that so much of Fstorm's realism is because of tonemapping, does not make sense. The fact that you estimate that Fstorm is more realistic 50% thanks to tonemapping is evidence of that.

You yourself claimed you are not an experienced Fstorm user - I am a very experienced dual user of both Corona and Fstorm (along with other engines). As mentioned in my last post I exclusively use Fstorm for high end product vis. Why? Because due to testing both engines extensively on many scenes back and forth, some even with very basic materials, the result is always poorer in Corona (and no, this isn't down in part to DOF settings, material conversion or a lack of knowledge of non "out of the box" Corona settings). It is down to tonemapping and how highlights and blacks are handled by each engine. I have tried for days in some circumstances to match the image in Corona and the same ultra-photographic result simply was not possible within Corona's VFB no matter any combo of curve adjustments, contrast tweaking, HC tweaking, Kim Luts, various other LUTS, Dubcats settings e.t.c. I'm simply not willing to go "yeah that looks pretty close", which might suffice for some.

Again, look at your own example (attached). Highlights have been visibly ruined and the wood tones are off and not reacting correctly as they should IRL - an observation I went into in detail previously. The average viewer may not spot this but in detailed viewing it is clearly apparent. If you don't think this affects overall photorealism, or certain edge cases in visuals in any meaningful way (would you concede to some degree?) then I don't know what to say to you.

Why am I bringing up Fstorm? Because out of all of the render engines I've used it simply produces the most true-to-life images possible right now (and yes, it requires settings tweaking just like every other engine, so it's not a case of n00bish "hurr muh default settings" user error). The tonal balance of the image one is able to get out of Fstorm is always superior, and I'm no Fstorm fanboy either - I wouldn't use it if I didn't have to, I would love to use Corona for everything due to it's superior feature set.

If not for tonemapping, what else do you think contributes to Fstorms superior photorealism? I've already mentioned several times on the forums better bitmap filtering/sharpness, bump mapping implementation, colour handling, pleasing noise patterns, and better DOF speed/sampling - however most of these can be worked around within Corona, Tonemapping however cannot be as it stands. Hence my prior statement of 50% (which was a fast and loose approximation, not verbatim gospel) - put a highly experienced user of both engines to work on the same scene in both engines, work around the quirks of both Corona and Fstorm, and the Fstorm image will be more photographic and pleasing to look at, fact. Case in point: look at anything Bertrand Benoit has produced (who I think most would regard as one of the best in the game that uses many different rendering engines), and compare to his Fstorm renders, and this was with his first trial of the engine: https://bertrand-benoit.com/blog/westkaai-via-fstorm/ there is always something "off" about his photo realistic Corona and Vray renders (a minor uncanny valley effect, i.e lacking in brain fooling true photorealism).

Side note: Fstorm as a rendering engine in general is terrible in some real world use cases; interiors with a lot of bounced light where it's annoying portal system will not save you. And not to mention VRAM limitations. It's lack of material and plugin support is also shocking (still doesn't have proper composite maps and multi-layered materials) - another reason I don't use it for anything more complex than product vis.
Title: Re: Tonemapping - Plz Halp
Post by: lolec on 2020-05-02, 04:51:50
Can you try to state what you think my point is? I think I've repeated myself and it's not working.

Do you think my point is:  Corona's tonemapping is fine, lets leave it like that ?  Because I've said the exact opposite.

Not sure what you are arguing with, so please state my point so I can continue the conversation with that as a starting point.
Title: Re: Tonemapping - Plz Halp
Post by: lolec on 2020-05-02, 06:11:36
Regarding that image of my earlier test, as others noted, I would have to use the exact same HDRI and closest as possible materials, not a simple conversion.

So I repeated the test. Same HDRI, Same LUT (KimAmlan02), Matched white balance. very simple materials.

Do you really see a 50% bump in realism in the Fstorm one? Maybe I don't have your eyes, it is entirely possible that I actually don't have the perceptual capacity.

(https://i.imgur.com/QTloeXK.jpg)

Anyway, now that I've conducted the test in a more proper manner, my point stands. I will write it in bold so you don't miss it and you stop arguing with something I'm not saying:

Fstorm has better tonemapping.   I wish Corona had a DSLR like tonemapping

However, I don't think that is the main reason for the Fstorm community producing seemingly more realistic images more consistently than the corona render community.
I think there is a small number of users (Agentdark45 included) who have superior understanding and perceptual abilities and actually notice the super slight differences between the two renderers, which are real and measurable.

But I believe what MOST people notice is a vibrant community that attracts great artists who are learning faster and feeling comfortable sooner with Fstorm, and thus, becoming good enough that, overall, the Fstorm community is producing better renders, more artistic, more realistic.

Just to be super clear, FSTORM HAS BETTER TONEMAPPING, 100% agree. And it has a real impact in realism! I wish Corona implements this soon
ps. I also wish corona becomes a lot more beginner and artist friendly by making it MUCH EASIER to produce the best possible images it already can, which, BTW would inevitably be WORST than Fstorm regarding tonemapping. At least until corona implements a better tonemapping, which I will continue to push and wish for.

 
Title: Re: Tonemapping - Plz Halp
Post by: cjwidd on 2020-05-02, 09:22:15
I know Dubcat posted some F-storm LUTs a while back, what are you feelings about using those in Corona? I know it's already been said that no amount of LUTs can make up the difference, just curioous.
Title: Re: Tonemapping - Plz Halp
Post by: lupaz on 2020-05-02, 16:11:54
I think the whole discussion would be over if we had the option of taking a raw rendering from corona ,absolutely linearly, like a raw photo from a camera and do tests outside of Corona. It's my understanding that this is not possible currently. Is it?




EDIT: This is hilarious:
https://www.dpreview.com/forums/thread/4119248
Quote
Nothing scientific, but ince the early 2000's I've always felt the look of Canon RAW images had a more plastic-like look (that's not negative - just different) than Nikon images, which seems more realistic.
Title: Re: Tonemapping - Plz Halp
Post by: Juraj on 2020-05-02, 16:27:46
I think the whole discussion would be over if we had the option of taking a raw rendering from corona ,absolutely linearly, like a raw photo from a camera and do tests outside of Corona. It's my understanding that this is not possible currently. Is it?

Did you mean F-Storm?

From Corona linear is easy, it's everything default (off & HC=1). Not sure how straight-forward it is from F-Storm.

That quote from DPReview.. photography "experts" are almost like homeopathy believers. "More depth", "More 3D", "Color science", etc.. are the most common nonsense they throw around constantly and discuss endlessly.

Title: Re: Tonemapping - Plz Halp
Post by: lupaz on 2020-05-02, 16:31:45
I think the whole discussion would be over if we had the option of taking a raw rendering from corona ,absolutely linearly, like a raw photo from a camera and do tests outside of Corona. It's my understanding that this is not possible currently. Is it?

Did you mean F-Storm?

From Corona linear is easy, it's everything default (off & HC=1). Not sure how straight-forward it is from F-Storm.

No. I meant Corona.
So pixels collected to form the rendering are not filtered at all?
If this is the case, renderings taken from Corona to Photoshop would look just as realistic as fstorm. That doesn't happen.
Title: Re: Tonemapping - Plz Halp
Post by: Juraj on 2020-05-02, 16:48:14
I think the whole discussion would be over if we had the option of taking a raw rendering from corona ,absolutely linearly, like a raw photo from a camera and do tests outside of Corona. It's my understanding that this is not possible currently. Is it?

Did you mean F-Storm?

From Corona linear is easy, it's everything default (off & HC=1). Not sure how straight-forward it is from F-Storm.

No. I meant Corona.
So pixels collected to form the rendering are not filtered at all?
If this is the case, renderings taken from Corona to Photoshop would look just as realistic as fstorm. That doesn't happen.

Can you elaborate? I don't really follow.
Title: Re: Tonemapping - Plz Halp
Post by: lupaz on 2020-05-02, 17:26:56
Sure.
Some are saying that what Corona needs is better tone mapping in order to get the same realism that you get from Fstorm.
Others are saying that the reason why Fstorm renderings feel more realistic is not tone mapping, but something else (to be determined).


Wouldn't it be a matter of taking a raw rendering from Corona and do the tone mapping in Photoshop?

This is what many of us do, and I feel that, even doing the tone mapping in photoshop, renderings from Corona don't look absolutely real, regardless of the scene, materials, and lighting. As someone said before in this thread, a photo looks real no matter the materials or lighting (unless you purposely try to make it appear not real).

So, again as someone said before, we are talking about 2 different things.

1- Tone mapping
2- realism.

To me to talk about tone mapping as the tool to make a rendering realistic doesn't make sense. And I think the confusion came from the beginning of this thread, when the OP wrote:

Quote
I'm either approaching lighting or tone mapping totally incorrectly; it is absolute guesswork every time, and rarely is it 'photorealistic'.

May be he didn't mean to use the word 'photrealistic'?

I do prefer to talk about making corona as realistic as possible, regardless tone mapping.
Title: Re: Tonemapping - Plz Halp
Post by: Juraj on 2020-05-02, 17:38:23
I see now, thank you. Yes that would point against tonemapping.

Title: Re: Tonemapping - Plz Halp
Post by: Designerman77 on 2020-05-02, 18:08:30
Right now I'm totally struggling with an empty bathroom scene my client wants rendered.
Mo matter what I do, it all the time looks unrealistic due to lighting, colors, etc.
When I turn up the contrasts, the shadow tones start to get too colorful, etc. Sure, one can "fix" it in post...

But as I mentioned before: the "proportions" of light/shadow, colors, etc. simply do look not realistic.
And from such a "soup" it is hard to do miracles in Photoshop.


Annoying... one loses hours and hours instead of simply getting jobs done.
Title: Re: Tonemapping - Plz Halp
Post by: Fluss on 2020-05-02, 21:31:24
Here is another misconception: Most of the time, if your render looks too saturated after tone mapping, it's because your diffuse (or any other colormap it is) was set too saturated on the first sight.
Title: Re: Tonemapping - Plz Halp
Post by: Designerman77 on 2020-05-02, 22:19:03
Here is another misconception: Most of the time, if your render looks too saturated after tone mapping, it's because your diffuse (or any other colormap it is) was set too saturated on the first sight.


Thanks for your reply, Fluss.
Neither the original JPG (texture) was too saturated, nor did I not additionally desaturate it in C4D. I do take care for this detail and almost always desaturate bitmaps.

Let´s be honest... one cannot talk away the fact that Corona is not so easy in the topic of tone mapping, etc.
I see this in hundreds and hundreds of renders, even from super good artists like Angelo Ferretti.
I bought some scenes from him to see how others work. Same thing with colors in many of his scenes, too.






Title: Re: Tonemapping - Plz Halp
Post by: twoheads on 2020-05-03, 00:18:13
If I may add my two cents, this discussion can be boiled down to braking bad's quote: "after all, how pure can pure be?"
For most people 96% purity is more than enough and for some people difference between 96 and 99 is not just noticeable it is like tremendous gulf.

Title: Re: Tonemapping - Plz Halp
Post by: bluebox on 2020-05-03, 00:52:31
Since I never tested fstorm I cant tell what causes this but I noriced this on Bertrands scene he sell. The Fstorm has much stronger direct light. Why is it? Clamped GI? Is it accidental or intentional. It gives the space more readable light in way that I doubt is due to tonemapping.

Someone would have to do a deep dive becayse the features have odd parity in behavior. Fstorm HDRI has two modes (weird option to cut off direct light?), their portal light effectively becomes new area light (like one option in Vray).

Very hard to pick out what exactly is the cause with so many variables.

With Dubcat, we suspected the shader. I wonder if something lije OrenNayar wouldnt cause more highlights from durect light?

I was trying to pinpoint what is the difference between the two engines and came to the same conclusion as you have Juraj that in Fstorm light seems to be more directional.

Flash-light renders looked totaly photorealistic back in the vray 3 days even with crappy shaders. This thogether with superior tonemapping is imho the key to ultimate realism.

Can't say tho whether the directionality comes from the shader as you guys with Dubcat suspected or form the GI algorithm.

Asked about Oren-nayar shader model in the daily builds but the devs haven't picked up the conversation. Take a look:

(https://cdna.artstation.com/p/assets/images/images/020/360/812/original/brian-leleux-concrete.gif?1567489016)

It instantly looks 10 times more realistic. The devs tho are busy with according to trello "key new features" like faster colour picker....
Title: Re: Tonemapping - Plz Halp
Post by: noldo on 2020-05-03, 07:56:58
Since I never tested fstorm I cant tell what causes this but I noriced this on Bertrands scene he sell. The Fstorm has much stronger direct light. Why is it? Clamped GI? Is it accidental or intentional. It gives the space more readable light in way that I doubt is due to tonemapping.

Someone would have to do a deep dive becayse the features have odd parity in behavior. Fstorm HDRI has two modes (weird option to cut off direct light?), their portal light effectively becomes new area light (like one option in Vray).

Very hard to pick out what exactly is the cause with so many variables.

With Dubcat, we suspected the shader. I wonder if something lije OrenNayar wouldnt cause more highlights from durect light?

I was trying to pinpoint what is the difference between the two engines and came to the same conclusion as you have Juraj that in Fstorm light seems to be more directional.

Flash-light renders looked totaly photorealistic back in the vray 3 days even with crappy shaders. This thogether with superior tonemapping is imho the key to ultimate realism.

Can't say tho whether the directionality comes from the shader as you guys with Dubcat suspected or form the GI algorithm.

Asked about Oren-nayar shader model in the daily builds but the devs haven't picked up the conversation. Take a look:

(https://cdna.artstation.com/p/assets/images/images/020/360/812/original/brian-leleux-concrete.gif?1567489016)

It instantly looks 10 times more realistic. The devs tho are busy with according to trello "key new features" like faster colour picker....

Absolutely, but fstorm also manages the diffuse roughness better, with much softer brightness variations as the roughness increases
Title: Re: Tonemapping - Plz Halp
Post by: cjwidd on 2020-05-03, 08:49:45
I really don't think Oren-Nayar is going to span the gulf between expectations about realism and what is currently achievable with Corona or any other renderer for that matter; you won't even notice Oren-Nayar unless the surface is very rough.
Title: Re: Tonemapping - Plz Halp
Post by: Designerman77 on 2020-05-03, 10:53:01
If I may add my two cents, this discussion can be boiled down to braking bad's quote: "after all, how pure can pure be?"
For most people 96% purity is more than enough and for some people difference between 96 and 99 is not just noticeable it is like tremendous gulf.



In my yesterdays "trivial bathroom"-scene, I again could see that it is not about "96% or 99%". :)
It was simply impossible to get a decent lighting and material look with the on-board tools in Corona.
Tweaking in PS Cam Raw was necessary, in order to get something out off the dull, raw render.

One can of course argue that it is the same with real RAW pics out of pro cameras.
BUT: sorry, 3D render engine users who need to meet client deadlines would have an easier life without massive post production.
In most cases, it is okay what comes directly out of Corona engine.
However, in this case of shitty, small room with sand colored tiles, etc. Corona clearly seems to meet its limits.
And yes, I also tried artificial lights inside the room... looked even more unnatural, despite trying different tones - from white to whatever, IES and non IES lights, etc.








 
Title: Re: Tonemapping - Plz Halp
Post by: ynotsop on 2020-05-03, 14:35:59
I love Corona but here is a nice example where Fstorm really shines:

Photo by Eric Floberg captured with Canon EOS-1D X MARK II (I think):
http://tiny.cc/l93aoz (http://tiny.cc/l93aoz)

Kitchen interior from Johannes:
https://viz.guru/wp-content/uploads/2019/11/Test8.jpg (https://viz.guru/wp-content/uploads/2019/11/Test8.jpg)
Title: Re: Tonemapping - Plz Halp
Post by: twoheads on 2020-05-03, 15:41:26
I love Corona but here is a nice example where Fstorm really shines:

Photo by Eric Floberg captured with Canon EOS-1D X MARK II (I think):
http://tiny.cc/l93aoz (http://tiny.cc/l93aoz)

Kitchen interior from Johannes:
https://viz.guru/wp-content/uploads/2019/11/Test8.jpg (https://viz.guru/wp-content/uploads/2019/11/Test8.jpg)
In my opinion this comparison proves absolutely nothing. Never tried fstorm so I can't tell for sure if its tonemapping is superior to corona's but yeah it looks like it is.

Have you seen fstorm's gallery on their website? (this one is for all of us) For my taste it shows variety of good and average shots both architectural and product design, exactly the same as corona's gallery and so what?
My point is that corona is a tool which in right hands can produce as good results as fstorm, maybe not as fast and easy but it definitely can. Poor models, low texture quality and so on can make the best renderer in the world just average. I don't think the way fstorm handles tonemapping is the answer here. We take Johannes's work as an example but he's one of the best in the business and even his work really stands off.

Lastly, "that horrible reinhard's burn in the background is unacceptable" type of clients are the worst, they really kill creativity :)

side note: it's just my personal opinion, no offence.




Title: Re: Tonemapping - Plz Halp
Post by: lupaz on 2020-05-03, 15:51:15
My point is that corona is a tool which in right hands can produce as good results as fstorm, maybe not as fast and easy but it definitely can.

Not saying this isn't true, but can you post a couple of images from any artist you want, made with corona, that tricks your brain to believe it's a photo?

edit: or maybe we should do a "photo or corona" game, to be fair to corona.
Title: Re: Tonemapping - Plz Halp
Post by: ynotsop on 2020-05-03, 17:20:41
We take Johannes's work as an example but he's one of the best in the business and even his work really stands off.

If we are trying to evaluate render engine realism it's only natural to compare real photos with the work of the best artists in the industry. The strange thing is that I saw the real kitchen photo I posted many months ago and it suddenly popped into my head while I was looking at Johaness' work. That's why I posted his work but in all fairness I should have posted another similar interior from (insert your favourite CGI artist) who uses Corona. If I take the best Corona image I can find and compare it to the two images I posted I can clearly see that Fstorm's render looks more photorealistic. Even when comparing it with the latest work from Jakub Cech which is drop dead gorgeous.

With regards to Fstorm the only way I can explain it is as if the materials have more "depth" along with what was already said about better tonemapping. In my opinion Fstorm users have the advantage of creating better looking materials because of the built-in tonemapping which gives them the ability to see materials how a camera would see it. In Corona you have to fiddle around with the sliders and LUTs until you feel satisfied and go on from there. Some Corona users get better at this, some master it, some don't and some never will.

I'm not trying to bash Corona because it's a great render engine and it got me excited about CGI again but as with all things there is always room for improvement.
Title: Re: Tonemapping - Plz Halp
Post by: Giona on 2020-05-03, 17:35:17

edit: or maybe we should do a "photo or corona" game, to be fair to corona.

We did that one year ago, and the survey results ended with more people saying that the photo was the render :)
Title: Re: Tonemapping - Plz Halp
Post by: twoheads on 2020-05-03, 17:45:40
In my opinion Fstorm users have the advantage of creating better looking materials because of the built-in tonemapping which gives them the ability to see materials how a camera would see it. In Corona you have to fiddle around with the sliders until you feel satisfied and go on from there. Some Corona users get better at this, some master it, some don't and some never will.

Agree. Built-in tonemapping really? I need to give fstorm a try and fiddle with it.

there is always room for improvement.
As above!

To be honest I like to make shaders. Tweaking it, changing parameters here and there and see results in IR. It gives me satisfaction and peace of mind :)
Title: Re: Tonemapping - Plz Halp
Post by: lolec on 2020-05-03, 17:53:19

Agree. Built-in tonemapping really? I need to give fstorm a try and fiddle with it.



This is what I've been saying. Corona should move the defaults to be tonemapped and more photographic instead of the plain meh look it has now as default.
Title: Re: Tonemapping - Plz Halp
Post by: twoheads on 2020-05-03, 18:08:47
We did that one year ago, and the survey results ended with more people saying that the photo was the render :)

I like to check these "real or fake" surveys out of curiosity and for fun, but unfortunately most of them make no sense at all. Most even lame renders look "real" in small resolution. In most cases to find out if you're dealing with CGI or photo all you need to do is zoom in.

What was the resolution of compared pictures, were they the same size? It's not an accusation, just asking.
Title: Re: Tonemapping - Plz Halp
Post by: Designerman77 on 2020-05-03, 19:00:13
We did that one year ago, and the survey results ended with more people saying that the photo was the render :)

I like to check these "real or fake" surveys out of curiosity and for fun, but unfortunately most of them make no sense at all. Most even lame renders look "real" in small resolution. In most cases to find out if you're dealing with CGI or photo all you need to do is zoom in.

What was the resolution of compared pictures, were they the same size? It's not an accusation, just asking.


You are right, yes and no... :) Pics with incorrect light calculation, color mapping, etc. look fake even in veeeery small size. :)))

Title: Re: Tonemapping - Plz Halp
Post by: Giona on 2020-05-03, 19:06:29
We did that one year ago, and the survey results ended with more people saying that the photo was the render :)

I like to check these "real or fake" surveys out of curiosity and for fun, but unfortunately most of them make no sense at all. Most even lame renders look "real" in small resolution. In most cases to find out if you're dealing with CGI or photo all you need to do is zoom in.

What was the resolution of compared pictures, were they the same size? It's not an accusation, just asking.

In the comments there were the two images in higher resolution.
I'm attaching them here.
But keep in mind that the survey was made for fun. I made the image in order to test and showcase the new caustics feature when it was released.
If you look at the images in high res, is quite obvious which one is the photo :)
Title: Re: Tonemapping - Plz Halp
Post by: BardhylM on 2020-05-03, 19:36:40
That photo looks so unrealistic, cameras should start using Fstorm tone mapping. I mean we do not need to have neutral results from render engine and apply our artistic choices.
We want Corona to do our job, completely. What's the point on putting materials and tweak the lights...etc... Why cant we have a "make my work" button.
And in the end, Corona is such a sweetheart, not trying to bash or anything... heehee.

- That is how some of you sound here, if you have not figure it out still.
I've been lurking here and don't get engaged in topics, mostly because they are always helpful and it's held up by really good members that keep on giving.
But this "Fstorm gud, others bed" has no place here i think. Yes it's been discussed here about tone mapping and ACES and everything, in a more educated approach.
Not in a "I think this looks better than this" approach, when there are biased views.

To everyone sorry for sounding so hostile, and making the forum a little bitter. Not my intention, I just had to...back in my cave again.
Title: Re: Tonemapping - Plz Halp
Post by: lupaz on 2020-05-03, 19:37:04
Ok. For those who want the challenge and don't know yet Bertrand Benoit's gallery:

Which of the following look like a photo? If you choose one done in Corona, then we know that Corona can reach maximum realism.
No need to answer in this thread. Just be honest to yourself and get your own conclusions.

Spoiler alert!: Do not scroll down to the description under each photo until you want to know which renderer was used.

1-https://www.flickr.com/photos/bbb3viz/49192470903/ (https://www.flickr.com/photos/bbb3viz/49192470903/)
2-https://www.flickr.com/photos/bbb3viz/48973629771/ (https://www.flickr.com/photos/bbb3viz/48973629771/)
3-https://www.flickr.com/photos/bbb3viz/48973807192/ (https://www.flickr.com/photos/bbb3viz/48973807192/)
4-https://www.flickr.com/photos/bbb3viz/48973807362/ (https://www.flickr.com/photos/bbb3viz/48973807362/)
5-https://www.flickr.com/photos/bbb3viz/29823282217/ (https://www.flickr.com/photos/bbb3viz/29823282217/)
6-https://www.flickr.com/photos/bbb3viz/29823284287/ (https://www.flickr.com/photos/bbb3viz/29823284287/)
7-https://www.flickr.com/photos/bbb3viz/29823282557/ (https://www.flickr.com/photos/bbb3viz/29823282557/)
8-https://www.flickr.com/photos/bbb3viz/37827903176/ (https://www.flickr.com/photos/bbb3viz/37827903176/)
9-https://www.flickr.com/photos/bbb3viz/24023863218/ (https://www.flickr.com/photos/bbb3viz/24023863218/)
10-https://www.flickr.com/photos/bbb3viz/36922536624/ (https://www.flickr.com/photos/bbb3viz/36922536624/)
11-https://www.flickr.com/photos/bbb3viz/35083230931/ (https://www.flickr.com/photos/bbb3viz/35083230931/)
12-https://www.flickr.com/photos/bbb3viz/31432084815/ (https://www.flickr.com/photos/bbb3viz/31432084815/)
13-https://www.flickr.com/photos/bbb3viz/29540095993/ (https://www.flickr.com/photos/bbb3viz/29540095993/)
14-https://www.flickr.com/photos/bbb3viz/28856986666/ (https://www.flickr.com/photos/bbb3viz/28856986666/)
15-https://www.flickr.com/photos/bbb3viz/22754589321/ (https://www.flickr.com/photos/bbb3viz/22754589321/)
Title: Re: Tonemapping - Plz Halp
Post by: Designerman77 on 2020-05-03, 19:40:01
That photo looks so unrealistic, cameras should start using Fstorm tone mapping. I mean we do not need to have neutral results from render engine and apply our artistic choices.
We want Corona to do our job, completely. What's the point on putting materials and tweak the lights...etc... Why cant we have a "make my work" button.
And in the end, Corona is such a sweetheart, not trying to bash or anything... heehee.

- That is how some of you sound here, if you have not figure it out still.
I've been lurking here and don't get engaged in topics, mostly because they are always helpful and it's held up by really good members that keep on giving.
But this "Fstorm gud, others bed" has no place here i think. Yes it's been discussed here about tone mapping and ACES and everything, in a more educated approach.
Not in a "I think this looks better than this" approach, when there are biased views.

To everyone sorry for sounding so hostile, and making the forum a little bitter. Not my intention, I just had to...back in my cave again.



Understanding your irony... however, I guess no-one of us here asks for a "do my work" button, only a "give me a base that works as expected". :)

Title: Re: Tonemapping - Plz Halp
Post by: Designerman77 on 2020-05-03, 19:47:21
We did that one year ago, and the survey results ended with more people saying that the photo was the render :)

I like to check these "real or fake" surveys out of curiosity and for fun, but unfortunately most of them make no sense at all. Most even lame renders look "real" in small resolution. In most cases to find out if you're dealing with CGI or photo all you need to do is zoom in.

What was the resolution of compared pictures, were they the same size? It's not an accusation, just asking.

In the comments there were the two images in higher resolution.
I'm attaching them here.
But keep in mind that the survey was made for fun. I made the image in order to test and showcase the new caustics feature when it was released.
If you look at the images in high res, is quite obvious which one is the photo :)




Without clicking on the images I would say that the first one is 3D.
Super hard shadows on the doors, light is too cold despite the warm wooden tone of the floor, too extreme caustic... colors somehow do not harmonize.
Title: Re: Tonemapping - Plz Halp
Post by: Designerman77 on 2020-05-03, 19:58:35
Ok. For those who want the challenge and don't know yet Bertrand Benoit's gallery:

Which of the following look like a photo? If you choose one done in Corona, then we know that Corona can reach maximum realism.
No need to answer in this thread. Just be honest to yourself and get your own conclusions.

Spoiler alert!: Do not scroll down to the description under each photo until you want to know which renderer was used.

1-https://www.flickr.com/photos/bbb3viz/49192470903/ (https://www.flickr.com/photos/bbb3viz/49192470903/)
2-https://www.flickr.com/photos/bbb3viz/48973629771/ (https://www.flickr.com/photos/bbb3viz/48973629771/)
3-https://www.flickr.com/photos/bbb3viz/48973807192/ (https://www.flickr.com/photos/bbb3viz/48973807192/)
4-https://www.flickr.com/photos/bbb3viz/48973807362/ (https://www.flickr.com/photos/bbb3viz/48973807362/)
5-https://www.flickr.com/photos/bbb3viz/29823282217/ (https://www.flickr.com/photos/bbb3viz/29823282217/)
6-https://www.flickr.com/photos/bbb3viz/29823284287/ (https://www.flickr.com/photos/bbb3viz/29823284287/)
7-https://www.flickr.com/photos/bbb3viz/29823282557/ (https://www.flickr.com/photos/bbb3viz/29823282557/)
8-https://www.flickr.com/photos/bbb3viz/37827903176/ (https://www.flickr.com/photos/bbb3viz/37827903176/)
9-https://www.flickr.com/photos/bbb3viz/24023863218/ (https://www.flickr.com/photos/bbb3viz/24023863218/)
10-https://www.flickr.com/photos/bbb3viz/36922536624/ (https://www.flickr.com/photos/bbb3viz/36922536624/)
11-https://www.flickr.com/photos/bbb3viz/35083230931/ (https://www.flickr.com/photos/bbb3viz/35083230931/)
12-https://www.flickr.com/photos/bbb3viz/31432084815/ (https://www.flickr.com/photos/bbb3viz/31432084815/)
13-https://www.flickr.com/photos/bbb3viz/29540095993/ (https://www.flickr.com/photos/bbb3viz/29540095993/)
14-https://www.flickr.com/photos/bbb3viz/28856986666/ (https://www.flickr.com/photos/bbb3viz/28856986666/)
15-https://www.flickr.com/photos/bbb3viz/22754589321/ (https://www.flickr.com/photos/bbb3viz/22754589321/)




Pics have massive post work... :)
Hard to compare or judge the render engine.
Title: Re: Tonemapping - Plz Halp
Post by: twoheads on 2020-05-03, 20:10:21
Ok. For those who want the challenge and don't know yet Bertrand Benoit's gallery:

Which of the following look like a photo? If you choose one done in Corona, then we know that Corona can reach maximum realism.
No need to answer in this thread. Just be honest to yourself and get your own conclusions.

Spoiler alert!: Do not scroll down to the description under each photo until you want to know which renderer was used.

1-https://www.flickr.com/photos/bbb3viz/49192470903/ (https://www.flickr.com/photos/bbb3viz/49192470903/)
2-https://www.flickr.com/photos/bbb3viz/48973629771/ (https://www.flickr.com/photos/bbb3viz/48973629771/)
3-https://www.flickr.com/photos/bbb3viz/48973807192/ (https://www.flickr.com/photos/bbb3viz/48973807192/)
4-https://www.flickr.com/photos/bbb3viz/48973807362/ (https://www.flickr.com/photos/bbb3viz/48973807362/)
5-https://www.flickr.com/photos/bbb3viz/29823282217/ (https://www.flickr.com/photos/bbb3viz/29823282217/)
6-https://www.flickr.com/photos/bbb3viz/29823284287/ (https://www.flickr.com/photos/bbb3viz/29823284287/)
7-https://www.flickr.com/photos/bbb3viz/29823282557/ (https://www.flickr.com/photos/bbb3viz/29823282557/)
8-https://www.flickr.com/photos/bbb3viz/37827903176/ (https://www.flickr.com/photos/bbb3viz/37827903176/)
9-https://www.flickr.com/photos/bbb3viz/24023863218/ (https://www.flickr.com/photos/bbb3viz/24023863218/)
10-https://www.flickr.com/photos/bbb3viz/36922536624/ (https://www.flickr.com/photos/bbb3viz/36922536624/)
11-https://www.flickr.com/photos/bbb3viz/35083230931/ (https://www.flickr.com/photos/bbb3viz/35083230931/)
12-https://www.flickr.com/photos/bbb3viz/31432084815/ (https://www.flickr.com/photos/bbb3viz/31432084815/)
13-https://www.flickr.com/photos/bbb3viz/29540095993/ (https://www.flickr.com/photos/bbb3viz/29540095993/)
14-https://www.flickr.com/photos/bbb3viz/28856986666/ (https://www.flickr.com/photos/bbb3viz/28856986666/)
15-https://www.flickr.com/photos/bbb3viz/22754589321/ (https://www.flickr.com/photos/bbb3viz/22754589321/)

10,11,13,14,15 look definitely better and more photorealistic than others. To be honest I thought they were photos.

I won ;)
Title: Re: Tonemapping - Plz Halp
Post by: Designerman77 on 2020-05-03, 20:46:53


10,11,13,14,15 look definitely better and more photorealistic than others. To be honest I thought they were photos.

I won ;)
[/quote]


Interesting... to me 10 looked super fake... the reflection on the floor slates, the tone of that little wooden furniture, the over saturation of the picture frame on the right,
the dull color tones... :)))))

Number 11 indeed looks nice... however it has visibly massive post work in it.

Look at 8 & 9... that smooth light changes without losing contrasts too much, without burning red tones in the woods, compression with less lost details, etc...
Typical characteristics of what I saw from FStorm until now.
And the image looks like having only minimal post work.
The eye can literally rest in that contrasts & tone mapping... THE typical difference I usually notice between photos and 3D with incorrect tone mapping, contrasts, etc.




Title: Re: Tonemapping - Plz Halp
Post by: PROH on 2020-05-03, 20:59:07
Hmmm.... To me number 8 & 9 are super dull - clamped highlights and grey'ish.

I think nr. 10 definately looks better and more (a)live.

Are we talking taste and style?
Title: Re: Tonemapping - Plz Halp
Post by: lupaz on 2020-05-03, 21:17:59
Are we talking taste and style?
No. Just realism.

To me too, #10 and #11 are the best overall, UNTIL I start looking in detail and I realize that nothing is really in focus or has the detail and sharpness of the real thing.
While #8 and #9 overall look kind of 3d-ish (especially the walls), but when I start to look in detail my eyes can focus and the sharpness is there, at least in one point of the image.

Does anyone else agree that with corona is hard to get sharp details? As if the sampling doesn't get deep in small interstices. With fstorm, even if the overall image is not better than corona, the details are superb.
Title: Re: Tonemapping - Plz Halp
Post by: Designerman77 on 2020-05-03, 21:24:54
Are we talking taste and style?
No. Just realism.

To me too, #10 and #11 are the best overall, UNTIL I start looking in detail and I realize that nothing is really in focus or has the detail and sharpness of the real thing.
While #8 and #9 overall look kind of 3d-ish (especially the walls), but when I start to look in detail my eyes can focus and the sharpness is there, at least in one point of the image.

Does anyone else agree that with corona is hard to get sharp details? As if the sampling doesn't get deep in small interstices. With fstorm, even if the overall image is not better than corona, the details are superb.



Yes, I agree with the sharpness point you mention.
Title: Re: Tonemapping - Plz Halp
Post by: Designerman77 on 2020-05-03, 21:34:32
Are we talking taste and style?
No. Just realism.

To me too, #10 and #11 are the best overall, UNTIL I start looking in detail and I realize that nothing is really in focus or has the detail and sharpness of the real thing.
While #8 and #9 overall look kind of 3d-ish (especially the walls), but when I start to look in detail my eyes can focus and the sharpness is there, at least in one point of the image.

Does anyone else agree that with corona is hard to get sharp details? As if the sampling doesn't get deep in small interstices. With fstorm, even if the overall image is not better than corona, the details are superb.



#10 ???
So the fake plastikish shader on the floor (okay, that can be fixed), the strange, muddy wood color on that little furniture, the washed out contrasts on the walls or the visible GI-splotches on the walls don't bother your eye? I also find the displacement on the stone wall looks flat... not 3-dimensional.
Also, lack of detail on that tall brown door... (with the door handle that's too low) :)

Interesting that to my eye this is the weakest picture of all.




Title: Re: Tonemapping - Plz Halp
Post by: lupaz on 2020-05-03, 21:35:08
On the other hand...

The following images aren't particularly sharp, and these are photos.
In the end it may be the fine detail that is hard to get with Corona, and not necessarily the sharpness. Which again, it makes me thing that the adaptive sampling doesn't get small enough, or stops too soon.

https://www.dwell.com/browse/photos/6658864961706086400 (https://www.dwell.com/browse/photos/6658864961706086400)
https://www.dwell.com/browse/photos/6658864980219744256 (https://www.dwell.com/browse/photos/6658864980219744256)
https://www.dwell.com/favorites/browse/photos/6424906192448507904 (https://www.dwell.com/favorites/browse/photos/6424906192448507904)
https://www.dwell.com/browse/photos/6656914047988609024 (https://www.dwell.com/browse/photos/6656914047988609024)
https://www.dwell.com/browse/photos/6656914034738802688 (https://www.dwell.com/browse/photos/6656914034738802688)
https://www.dwell.com/browse/photos/6545381783257796608 (https://www.dwell.com/browse/photos/6545381783257796608)
https://www.dwell.com/browse/photos/6651308624662908928 (https://www.dwell.com/browse/photos/6651308624662908928)
https://www.dwell.com/browse/photos/6653000498230480896 (https://www.dwell.com/browse/photos/6653000498230480896)
Title: Re: Tonemapping - Plz Halp
Post by: Designerman77 on 2020-05-03, 21:38:54
Hmmm.... To me number 8 & 9 are super dull - clamped highlights and grey'ish.

I think nr. 10 definately looks better and more (a)live.

Are we talking taste and style?

They are dull, yes... but the proportions in the contrasts and colors look like in photography! They look correct, as one would expect it in a photo.
Cranking up contrasts or highlights according to your taste shouldn't be a problem... especially when images (like this one) have so much (optical) information in it.


Title: Re: Tonemapping - Plz Halp
Post by: lupaz on 2020-05-03, 21:55:28
And here there's a comparison of the same scene, just for the fun of the experiment. Unfortunately the lighting is slightly different, even if the HDRI is the same.



(https://i.imgur.com/Bgr2NM7.jpg)
Title: Re: Tonemapping - Plz Halp
Post by: twoheads on 2020-05-03, 22:14:36
I know few professional photographers and they use PS extensively. I'm not talking about developing process but pure postproduction. They're like michelin star chefs with butter. They put tons of this s..t everywhere. It takes a lot of time to make photo look great for publication believe me.

My reply about "which render looks better"  wasn't of course 100% serious. Now Imagine fstorm dev watching this topic laughing at us. "what the hell are they trying to achieve here?" :)

As for westkaai, we are discussing work we all know quite well (most of us) and I don't think we are talking about realism exclusively (it's not possible at this point). It would be fair to test both engines in some kind of blind test. Let's say 30 selected images we all have never seen before:  10 for corona, 10 for fstorm and 10 real photos and then we could debate for days and days and finally get conclusion "fstorm is 18% more photorealistic" who cares?

I'd really like to know what devs think about improvements we are talking about, I don't see any waving hands...
Title: Re: Tonemapping - Plz Halp
Post by: Designerman77 on 2020-05-03, 23:38:06
I know few professional photographers and they use PS extensively. I'm not talking about developing process but pure postproduction. They're like michelin star chefs with butter. They put tons of this s..t everywhere. It takes a lot of time to make photo look great for publication believe me.

My reply about "which render looks better"  wasn't of course 100% serious. Now Imagine fstorm dev watching this topic laughing at us. "what the hell are they trying to achieve here?" :)

As for westkaai, we are discussing work we all know quite well (most of us) and I don't think we are talking about realism exclusively (it's not possible at this point). It would be fair to test both engines in some kind of blind test. Let's say 30 selected images we all have never seen before:  10 for corona, 10 for fstorm and 10 real photos and then we could debate for days and days and finally get conclusion "fstorm is 18% more photorealistic" who cares?

I'd really like to know what devs think about improvements we are talking about, I don't see any waving hands...



Well, me for example, I do care... :)
And however... in my opinion, fiddling for hours in PS on an image cannot be the way to go.
3D software devs cannot expect that from users, nor do our clients want to wait for ages or pay a fortune for a single pic.
Title: Re: Tonemapping - Plz Halp
Post by: Designerman77 on 2020-05-03, 23:39:52
And here there's a comparison of the same scene, just for the fun of the experiment. Unfortunately the lighting is slightly different, even if the HDRI is the same.



(https://i.imgur.com/Bgr2NM7.jpg)


Thumbs up.
As I mentioned in some post before... you often see the better tone mapping once you desaturate an image to BW.
Cool test you did again!

Clearly visible differences...
Title: Re: Tonemapping - Plz Halp
Post by: Juraj on 2020-05-03, 23:55:41
I would love to see the test above continued if you'll find time. Isn't the difference coming from mirrored HDRi? Every single loader, every engine, has this standardized differently (including starting angle!).

The region, top left corner is the most interesting difference.
Title: Re: Tonemapping - Plz Halp
Post by: cjwidd on 2020-05-04, 00:31:19
😄
Title: Re: Tonemapping - Plz Halp
Post by: lupaz on 2020-05-04, 02:28:04
I'm keeping noise in the images so we don't pay too much attention to shaders.

They're pretty much the same in my opinion.

What it is important, I think, and may be the reason why people think the problem is tone mapping, is that the shadows on the corners are stronger in Fstorm, even when the overall image has less contrast.
With the corona image, even after applying a strong post production, the corners will not have that nice shadow that you have in the fstorm image. May be using AO?
So I agree with the person that said that highlights and shadows are stronger in fstorm.

Also I notice that the geometry gets defined better (or sooner?) in fstorm. Look at the knob on the door, or the charger in the post on the counter

Just a note: I'm not saying that Fstorm is a better engine than Corona. Just comparing.

(https://i.imgur.com/yrHQsY6.jpg)


Title: Re: Tonemapping - Plz Halp
Post by: lolec on 2020-05-04, 04:05:35
I notice you didn't enable LUT or modify Hightlight compression. Any reason why? Fstorm applies a LUT by default, so this is not a oranges to oranges compression, just wondering if you have a reason?
Title: Re: Tonemapping - Plz Halp
Post by: Fluss on 2020-05-04, 07:38:06
Every single loader, every engine, has this standardized differently (including starting angle!).

This what hurt the most in those comparisons... Fstorm loader is indeed mirrored.. It seems like lupaz corrected it in the last render, not saying much about it.. Guys, checking the technical side is crucial in those kinds of comparisons, so as explaining the process... Everybody was taking a conclusion on renders with different lighting.... That sucks.

A lot of posts above were complete garbage.. comparing real photos to renders with completely different subjects, no controlled environment etc etc.. No need to expand more, this is useless. Let's not make this thread a complete junk pile.

Please lupaz, keep conducting your current test, it's interesting. But please make it fair and accurate. First thing would be to make them 1:1. So no missing materials/maps (if something do not work in an engine, should be changed by something that both supports in both scenes), same lighting (seems to be a little bit off still, based on the highlights upstairs), and a matching exposure. This would be a good starting point on which you can iterate.

Also, Fstorm as no caching solution, it's BF+BF. Not saying you have to change this one but this might explain some really fine details discrepancy some are talking about. Fstorm was remapping the glossiness range from [0.4;1.0] to [0.0-1.0], is it still the case? This could have a huge impact so keep that in mind.
Title: Re: Tonemapping - Plz Halp
Post by: cjwidd on 2020-05-04, 08:01:06
^thank you @Fluss
Title: Re: Tonemapping - Plz Halp
Post by: Designerman77 on 2020-05-04, 10:21:19
Every single loader, every engine, has this standardized differently (including starting angle!).

This what hurt the most in those comparisons... Fstorm loader is indeed mirrored.. It seems like lupaz corrected it in the last render, not saying much about it.. Guys, checking the technical side is crucial in those kinds of comparisons, so as explaining the process... Everybody was taking a conclusion on renders with different lighting.... That sucks.

A lot of posts above were complete garbage.. comparing real photos to renders with completely different subjects, no controlled environment etc etc.. No need to expand more, this is useless. Let's not make this thread a complete junk pile.

Please lupaz, keep conducting your current test, it's interesting. But please make it fair and accurate. First thing would be to make them 1:1. So no missing materials/maps (if something do not work in an engine, should be changed by something that both supports in both scenes), same lighting (seems to be a little bit off still, based on the highlights upstairs), and a matching exposure. This would be a good starting point on which you can iterate.

Also, Fstorm as no caching solution, it's BF+BF. Not saying you have to change this one but this might explain some really fine details discrepancy some are talking about. Fstorm was remapping the glossiness range from [0.4;1.0] to [0.0-1.0], is it still the case? This could have a huge impact so keep that in mind.


May I ask what exactly is your point? You claim that Corona is a perfect render engine and devs. could go home and stop optimizing it?
It is NOT perfect and still needs a good amount of work until it can be called really photo-realistic. PERIOD !

Calling other peoples` thoughts "garbage" is an offense to all the guys here that take their precious time, energy and experience, willing to
make this great software even better.

I am sure the devs at Corona are not offended that users make suggestions. Actually, the nowadays quality of this software is based on the open minded attitude of the Corona dev team, not on an attitude of ignorance and "defending the existing limitations".
Title: Re: Tonemapping - Plz Halp
Post by: jms.lwly on 2020-05-04, 10:45:59
it is absolute guesswork every time

Revisiting cjwidd's original point (things seem to have deviated from his original question - although brought about an interesting new conversation...) - every project I have the same back and forth in my setup:-

Use a LUT? Don't use a LUT, just use HC and Filmic...
Do less in VFB and more in Photoshop? Try to squeeze the very best output from VFB...
Use just HDRI for environment lighting? Use Corona Sun/Sky for lighting...

I realise with the all of above there is no correct answer - but I think this was the original question, which I fundamentally struggle with too.
Title: Re: Tonemapping - Plz Halp
Post by: Fluss on 2020-05-04, 10:54:00
May I ask what exactly is your point? You claim that Corona is a perfect render engine and devs. could go home and stop optimizing it?
It is NOT perfect and still needs a good amount of work until it can be called really photo-realistic. PERIOD !

Calling other peoples` thoughts "garbage" is an offense to all the guys here that take their precious time, energy and experience, willing to
make this great software even better.

I am sure the devs at Corona are not offended that users make suggestions. Actually, the nowadays quality of this software is based on the open minded attitude of the Corona dev team, not on an attitude of ignorance and "defending the existing limitations".

I'm just asking for a pragmatic approach. If you follow my post history, you'll actually see that I'm trying to push for some improvements as well. But come on, comparing a photograph of a kitchen with a render of a completely different scene, Making a poll with random renders... what's the point of this? This is useless as this proves nothing -> garbage. I'm not defending anything, you do.

I'm sorry for you but @BardhylM was right.

disclaimer : just to clarify, when I said no controlled environment, I was talking about the process of comparing real photos to renders. That part was not about lupaz test which is great even if it has some flaws I pointed out. So your test lupaz was not included in the garbage stuff.
Title: Re: Tonemapping - Plz Halp
Post by: Designerman77 on 2020-05-04, 11:32:31
May I ask what exactly is your point? You claim that Corona is a perfect render engine and devs. could go home and stop optimizing it?
It is NOT perfect and still needs a good amount of work until it can be called really photo-realistic. PERIOD !

Calling other peoples` thoughts "garbage" is an offense to all the guys here that take their precious time, energy and experience, willing to
make this great software even better.

I am sure the devs at Corona are not offended that users make suggestions. Actually, the nowadays quality of this software is based on the open minded attitude of the Corona dev team, not on an attitude of ignorance and "defending the existing limitations".

I'm just asking for a pragmatic approach. If you follow my post history, you'll actually see that I'm trying to push for some improvements as well. But come on, comparing a photograph of a kitchen with a render of a completely different scene, Making a poll with random renders... what's the point of this? This is useless as this proves nothing -> garbage. I'm not defending anything, you do.

I'm sorry for you but @BardhylM was right.

disclaimer : just to clarify, when I said no controlled environment, I was talking about the process of comparing real photos to renders. That part was not about lupaz test which is great even if it has some flaws I pointed out. So your test lupaz was not included in the garbage stuff.


You split hairs in a problem that is visible even to a half blind. MY opinion.
The goal of this software ist to work photo real. Nothing less.

Improvements are not done by neglecting the flaws.
Do you also react like this if your clients ask for improvements in your renders? Like "shut up with your garbage, they are perfect" ???
Title: Re: Tonemapping - Plz Halp
Post by: Fluss on 2020-05-04, 11:43:25
I did not ask anyone to shut up.

I'm not neglecting anything.

We are trying to answer one question. Not "did you see it ?", not "Do you like it ?", but "Why?". That's the point.
Title: Re: Tonemapping - Plz Halp
Post by: cjwidd on 2020-05-04, 11:46:23
Eh, I feel like some of these comments are unnecessarily hostile and counterproductive...
Title: Re: Tonemapping - Plz Halp
Post by: ynotsop on 2020-05-04, 12:02:03
That's fine, I'll take the heat for posting those two pictures, but to me it illustrates how Fstorms renders mimic a camera. And I don't have to have a render based on a real photo to see it. The subjects are different but the overall materialism is very similar. To me the pictures look like they were taken with the same camera which goes back to my first point. Maybe I'm the only one seeing it and that's fine too.

The only thing garbage here is the attitude some of you have, and according to some only the ultra knowledgeable should be allowed to participate in discussions and the others can observe from their caves. If you don't agree with someone you can at least express it in a polite manner and we can keep the conversation on a level. I think it's fair to say that everyone participating in these forums are doing so with good intentions.

Eh, I feel like some of these comments are unnecessarily hostile and counterproductive...

I agree.
Title: Re: Tonemapping - Plz Halp
Post by: Fluss on 2020-05-04, 13:05:05
The thing is plenty of threads like this exist on the forum and they're all the same -> "Look how it's good", "Are you blind", "We want the same". Basically people moaning they want photo-real results without doing their part.
People keep posting example pictures from the internet, which they have no clue how they were made, how much post-production there is, how much effort the artist put in to look like that etc etc... Basically attributing the fact that the image looks good because of the renderer and not because of the artist.

So I tried to orient the discussion on a break it down approach. If it is so simple and Fstorm is so magical, show us examples you made and compare the results with what you can produce in Corona, 1:1. It's easy to make claims, it's less to prove them. The side by side comparison I've seen so far are not as mindblowing as some of you claim it to be. I never denied there is something common to some of the Fstorm renders we've seen, I'm just inclined to understand why rather than asking for something blindly...

Everybody is allowed to express an opinion, including me! So if I find these ever returning comments useless, I am allowed to express it. The thing is those are just making the thread going in circles like the 99 others before. Now if I offended some of you by calling those garbage, I apologize for that. I'm just tired of seeing the same stuff over and over again.

Title: Re: Tonemapping - Plz Halp
Post by: bluebox on 2020-05-04, 13:22:56
I think we should wrap this up at this point to a conclusion that everyone is trying to contribute towards the same goal - improvements in the area that as we can all see is really really wanted by many.

Current tone mapping is not working as it should in many areas that were discussed back and forth many times.
Original contrast destroys blacks, oversaturates colours to a point that you are no longer able to see the original texture used which is really annoying when working with product design or anything that requires more than just a punchy-candy picture.
LUTs are also not the way to go, they should be used to get a certain degree of mood imho, not the base acceptable picture.

What concerns me the most is the fact that this in one of many topics abut all those issues and we still can't get noone from the Corona team to participate.
We still get all those "key new features" like faster color picker and the important stuff as we can see and extrapolate from the most wanted features poll gets neglected.

Those discussions basicaly IMHO end up in a vacuum and we get this BS policy of a roadmap that is all but "no promisses".
If the community wants certain features and they end up not being developed and we can't get any promisses then I vote for bringing back the box licence so I can upgrade when and only when the features that community wants get implemented.

My few cents.
Title: Re: Tonemapping - Plz Halp
Post by: agentdark45 on 2020-05-04, 14:37:20
Regarding that image of my earlier test, as others noted, I would have to use the exact same HDRI and closest as possible materials, not a simple conversion.

So I repeated the test. Same HDRI, Same LUT (KimAmlan02), Matched white balance. very simple materials.

Do you really see a 50% bump in realism in the Fstorm one? Maybe I don't have your eyes, it is entirely possible that I actually don't have the perceptual capacity.

(https://i.imgur.com/QTloeXK.jpg)

Anyway, now that I've conducted the test in a more proper manner, my point stands. I will write it in bold so you don't miss it and you stop arguing with something I'm not saying:

Fstorm has better tonemapping.   I wish Corona had a DSLR like tonemapping

However, I don't think that is the main reason for the Fstorm community producing seemingly more realistic images more consistently than the corona render community.
I think there is a small number of users (Agentdark45 included) who have superior understanding and perceptual abilities and actually notice the super slight differences between the two renderers, which are real and measurable.

But I believe what MOST people notice is a vibrant community that attracts great artists who are learning faster and feeling comfortable sooner with Fstorm, and thus, becoming good enough that, overall, the Fstorm community is producing better renders, more artistic, more realistic.

Just to be super clear, FSTORM HAS BETTER TONEMAPPING, 100% agree. And it has a real impact in realism! I wish Corona implements this soon
ps. I also wish corona becomes a lot more beginner and artist friendly by making it MUCH EASIER to produce the best possible images it already can, which, BTW would inevitably be WORST than Fstorm regarding tonemapping. At least until corona implements a better tonemapping, which I will continue to push and wish for.

Apologies if I missed the spirit of your post, it seemed contradictory at the time of posting. I'm glad to see you are supporting the call for improved tonemapping in Corona.

My main contention here is that some posters are claiming:

1. "Everything is fine with Corona as is, zero perceptual difference in tone-mapping between Fstorm and Corona; the issue is noobish user error being fixated on stock settings".
2. While other posters are stating that there is a clear and obvious limitation with Corona's tonemapping (despite Bertrand Benoit levels of Corona mastery and tweaking), and we want improved colour space/ACES like tonemapping implemented as a priority over other seemingly trivial features that eat up precious dev time.

Regarding your recent comparison, yes there is a difference between the two (perhaps not 50%) but I can clearly see the black crush in the shadows issue I have mentioned before in trying to achieve a contrasty punchy image whilst retaining not overly clamped highlights (look at how much detail is lost in the lower right shadow on the floor in the Corona version, along with the shadow at the base of the exterior sphere, the soft shadow gradient on the left hand interior wall, and the tendancy for Corona to go to pure black in corner gaps - the dynamic range of the shadows have been butchered). Now scale this issue up to images that mostly deal with subtle tonal variations (i.e moody or brightly lit product shots).

As a side note outside of tonemapping, you can also see the filtering issue I mentioned previously in the Corona example. Look at how much detail has been smoothed out of the concrete walls and wood material in the Corona version.
Title: Re: Tonemapping - Plz Halp
Post by: Juraj on 2020-05-04, 14:52:58
Less strawmen and attacks or devs will lock this epic thread 😀

Everyone really wants the same, there is just various level of allergy to hyperbolic expectations and conclusions.
This might be tough topic even for devs, I've only ever seen Pixar doing indepth reaserch into realism that goes beyond the technical part, esp. because so much of it strays into subjective.

I personally love comparisons, I know they are flawed but lit can be peered from them. Fluss is only suggesting to do this more thoroughly as it will help avoid reaching premature and incorrect conclusions.

That takes unfortunately unholy amount of effort & time, which everyone lacks. So all my respect to people with patience to fiddle with this. More tests, less assured conclusions.
Title: Re: Tonemapping - Plz Halp
Post by: ynotsop on 2020-05-04, 16:01:56
I completely agree with the fact that in the end things have to be investigated in a practical manner. It's cool to see these comparisons lolec and lupaz are doing. It's also saddening to see that this issue has been already brought up way back in 2017 (or maybe even before that?).
Title: Re: Tonemapping - Plz Halp
Post by: lupaz on 2020-05-04, 16:34:52
@Fluss
You said it yourself:
So photorealism really isn't that simple to define as there is a whole lot of intricacies. The key is to use references and observe the world around you. I often look at light interactions around me and a lot of these observations are making me think "If I'd see this in one of my renders, i'd probably think this is a bug".

It would be really interesting to make a thread with great images and review them to highlight why it works well.

The reason for showing renderings and also photos is to observe.
You can do all the tests you want being methodical and practical, but in the end there's also a perception component that we can learn from looking at different images.
So I disagree. It's not garbage. It's learning. Isn't AI based on this?

If I may add my two cents, this discussion can be boiled down to braking bad's quote: "after all, how pure can pure be?"
For most people 96% purity is more than enough and for some people difference between 96 and 99 is not just noticeable it is like tremendous gulf.
and finally get conclusion "fstorm is 18% more photorealistic" who cares?

The whole discussion, I think, it's because we strive to make more compelling images. Images that sell.
Clients will "buy" faster (18%? :)) an image if they FEEL they like it.

Some Fstorm images have a feeling that is very attractive.
We're trying to pin-point it, right?


Original contrast destroys blacks, oversaturates colours to a point that you are no longer able to see the original texture used which is really annoying when working with product design or anything that requires more than just a punchy-candy picture.

How do you guys know that this is the cause? A bad tone mapping...
Could it be that the shadows are wrongly represented by the engine in the first place, making them more bland with a gradient that makes contrast to flatten them?

That's what I'm trying to do with the black and white noisy tests:
I want to discard tone mapping, sharpening, LUT, bloom, DOF, color, textures, contrast; and I want to compare the core of the engine: How it resolves light and shadows, antialiasing, BRDF and sampling of small objects and details.


Title: Re: Tonemapping - Plz Halp
Post by: lupaz on 2020-05-04, 17:11:38
I notice you didn't enable LUT or modify Hightlight compression. Any reason why? Fstorm applies a LUT by default, so this is not a oranges to oranges compression, just wondering if you have a reason?

What I tried to do was to remove from the Fstorm frame buffer all post production. For this test I didn't care about Fstorm defaults. If we remove post production stuff and end up with the same rendering as corona, that would mean that you can get an Fstorm render with little effort, with Corona's controls or other software.

What I want to do next is add DOF to the test and see what happens.
Title: Re: Tonemapping - Plz Halp
Post by: Fluss on 2020-05-04, 17:23:48
LMAO, you're quoting me totally out of context. If you still did not get my point then there is not so much I can do. Anyway, I'll leave it here as I don't want to pollute the thread even more. let's move on
Title: Re: Tonemapping - Plz Halp
Post by: Designerman77 on 2020-05-04, 17:42:45
I did not ask anyone to shut up.

I'm not neglecting anything.

We are trying to answer one question. Not "did you see it ?", not "Do you like it ?", but "Why?". That's the point.


Then I'm totally with you. :)
Title: Re: Tonemapping - Plz Halp
Post by: Designerman77 on 2020-05-04, 17:54:14
I think we should wrap this up at this point to a conclusion that everyone is trying to contribute towards the same goal - improvements in the area that as we can all see is really really wanted by many.

Current tone mapping is not working as it should in many areas that were discussed back and forth many times.
Original contrast destroys blacks, oversaturates colours to a point that you are no longer able to see the original texture used which is really annoying when working with product design or anything that requires more than just a punchy-candy picture.
LUTs are also not the way to go, they should be used to get a certain degree of mood imho, not the base acceptable picture.

What concerns me the most is the fact that this in one of many topics abut all those issues and we still can't get noone from the Corona team to participate.
We still get all those "key new features" like faster color picker and the important stuff as we can see and extrapolate from the most wanted features poll gets neglected.

Those discussions basicaly IMHO end up in a vacuum and we get this BS policy of a roadmap that is all but "no promisses".
If the community wants certain features and they end up not being developed and we can't get any promisses then I vote for bringing back the box licence so I can upgrade when and only when the features that community wants get implemented.

My few cents.




With your observations about tone mapping misbalance, burning colors, exaggerated contrasts in blacks, etc. you 100% nailed it!
And that's also basically my point: there is no way to talk those facts away.

However, regarding your assumption that Corona devs "don't care"... hmmm... I am sure the do care and read this thread very carefully, since it
criticized the very core of Corona - in a pro active way. :)
About one year ago, some guys and me massively complained about the new denoiser messing up round edges & bump textures to a point that one could not work anymore.
Relatively quickly. the devs implemented the new AI denoiser that does a good job.

Wouldn't be surprised to see a new, advanced tone mapping in Cor 7.
Let´s hope.






Title: Re: Tonemapping - Plz Halp
Post by: Designerman77 on 2020-05-04, 18:05:08
Regarding your recent comparison, yes there is a difference between the two (perhaps not 50%) but I can clearly see the black crush in the shadows issue I have mentioned before in trying to achieve a contrasty punchy image whilst retaining not overly clamped highlights (look at how much detail is lost in the lower right shadow on the floor in the Corona version, along with the shadow at the base of the exterior sphere, the soft shadow gradient on the left hand interior wall, and the tendancy for Corona to go to pure black in corner gaps - the dynamic range of the shadows have been butchered). Now scale this issue up to images that mostly deal with subtle tonal variations (i.e moody or brightly lit product shots).

As a side note outside of tonemapping, you can also see the filtering issue I mentioned previously in the Corona example. Look at how much detail has been smoothed out of the concrete walls and wood material in the Corona version.
[/quote]






Brilliant eye & observation, Sir!

Exactly those things ( black shadow areas, wrong dark-light transitions, etc.) make you literally feel like somehow not being abele to look at an image and get the information your eye looks for.
A bit like listening to a music recording that has distorted frequencies.


Title: Re: Tonemapping - Plz Halp
Post by: hldemi on 2020-05-04, 18:32:51
I notice you didn't enable LUT or modify Hightlight compression. Any reason why? Fstorm applies a LUT by default, so this is not a oranges to oranges compression, just wondering if you have a reason?

What I tried to do was to remove from the Fstorm frame buffer all post production. For this test I didn't care about Fstorm defaults. If we remove post production stuff and end up with the same rendering as corona, that would mean that you can get an Fstorm render with little effort, with Corona's controls or other software.

What I want to do next is add DOF to the test and see what happens.

There was similar thread on Fstorm FB group and I remember Johannes Lindqvist saying that They tested same scene with Fstorm and Corona and when they turned off Fstorm tonemapping the render was practically identical. Also Andrey said Fstorm uses Canon 300D LUT right now as default. SO to try that LUT in corona and compare images would be interesting.
Title: Re: Tonemapping - Plz Halp
Post by: lolec on 2020-05-04, 19:09:25
Regarding your recent comparison, yes there is a difference between the two (perhaps not 50%) but I can clearly see the black crush in the shadows issue I have mentioned before in trying to achieve a contrasty punchy image whilst retaining not overly clamped highlights (look at how much detail is lost in the lower right shadow on the floor in the Corona version, along with the shadow at the base of the exterior sphere, the soft shadow gradient on the left hand interior wall, and the tendancy for Corona to go to pure black in corner gaps - the dynamic range of the shadows have been butchered). Now scale this issue up to images that mostly deal with subtle tonal variations (i.e moody or brightly lit product shots).

As a side note outside of tonemapping, you can also see the filtering issue I mentioned previously in the Corona example. Look at how much detail has been smoothed out of the concrete walls and wood material in the Corona version.


Brilliant eye & observation, Sir!

Exactly those things ( black shadow areas, wrong dark-light transitions, etc.) make you literally feel like somehow not being abele to look at an image and get the information your eye looks for.
A bit like listening to a music recording that has distorted frequencies.

I hope you don't take this the wrong way, but I think the fairest way to do a blind test is when the participants are actually blind.

I swapped the Corona and Fstorm renders, I removed the watermark from the Fstorm Render and added a Fstorm Watermark to the Corona render one.

I don't know what that means, and I don't mean to say that there is no difference or that Fstorm doesn't have some areas where it is superior. But at least in this particular test, it seems like Corona actually exhibits the great properties you are looking for, as long as it has a Fstorm watermark on top of it.

Hope this information can help us all reach further conclusions :) Please don't punch me !
Title: Re: Tonemapping - Plz Halp
Post by: Designerman77 on 2020-05-04, 19:51:25
I hope you don't take this the wrong way, but I think the fairest way to do a blind test is when the participants are actually blind.

I swapped the Corona and Fstorm renders, I removed the watermark from the Fstorm Render and added a Fstorm Watermark to the Corona render one.

I don't know what that means, and I don't mean to say that there is no difference or that Fstorm doesn't have some areas where it is superior. But at least in this particular test, it seems like Corona actually exhibits the great properties you are looking for, as long as it has a Fstorm watermark on top of it.

Hope this information can help us all reach further conclusions :) Please don't punch me !
[/quote]



So you basically say that you tricked everyone here by swapping the FS-watermark and put it on Corona render?
Okay... however, those characteristics others mentioned ( too black shadows, etc. etc. ) actually do exist in Corona when you touch the contrast and I observe it day by day.

I don't know what you did with the FStorm render... but from the FStorm renders I have seen up to date, I cannot remember those burnt colors, black shadows with no detail, etc.
This is totally non typical for F-storm.

So?

Sorry, but this all is surely not a "mass hallucination". :)
Title: Re: Tonemapping - Plz Halp
Post by: lolec on 2020-05-04, 20:10:02
If it wasn't a typical Fstorm render, wouldn't you say you would have been able to notice?

Not only you didn't immediately notice but you even complained about the same things you are complaining about corona. And not only you, so maybe there is something else to it than objective observation.

Not sure why you label it as "tricked"  we are talking about comparisons and every serious study requires the elimination of variables.

I'm sorry you didn't like the results of the experiment, I bet that if the result was different and you actually noticed, you would have felt really good about that fact, and confirm your previous notions. So I think just because you didn't get the expected result, there is no reason to say "I did something to the Fstorm version".

Title: Re: Tonemapping - Plz Halp
Post by: cjwidd on 2020-05-04, 21:12:06
I created this thread with a much more pedestrian goal in mind, basically to ask how others use the tonemapping features. Think of the following as a series of T/F statements, For example:

In general...
Title: Re: Tonemapping - Plz Halp
Post by: cjwidd on 2020-05-04, 21:33:26
There was similar thread on Fstorm FB group and I remember Johannes Lindqvist saying that They tested same scene with Fstorm and Corona and when they turned off Fstorm tonemapping the render was practically identical. Also Andrey said Fstorm uses Canon 300D LUT right now as default. SO to try that LUT in corona and compare images would be interesting.

I don't really appreciate the F-storm vs. Corona Renderer discussion happening on this thread, but this post^ is a really interesting contribution. It sounds like Johannes (unsurprisingly) already did controlled experiments - pretty compelling.
Title: Re: Tonemapping - Plz Halp
Post by: Designerman77 on 2020-05-04, 21:46:06
If it wasn't a typical Fstorm render, wouldn't you say you would have been able to notice?

Not only you didn't immediately notice but you even complained about the same things you are complaining about corona. And not only you, so maybe there is something else to it than objective observation.

Not sure why you label it as "tricked"  we are talking about comparisons and every serious study requires the elimination of variables.

I'm sorry you didn't like the results of the experiment, I bet that if the result was different and you actually noticed, you would have felt really good about that fact, and confirm your previous notions. So I think just because you didn't get the expected result, there is no reason to say "I did something to the Fstorm version".


Why should I be "disappointed"???? I am very glad about it, actually, since I work 100% in Corona and very much appreciate this program.
But: it still remains a fact that - despite that funny inversion of pics - tons of people see what all of us discussed about.
I don´t think that it is because FStorm users are all geniuses and Corona users just dilettantes.

The question remains: do we (the users) want Corona to evolve as a render engine, or rather relativize and discuss those things away which could be improved?

I claim that a few test do not have the same meaningfulness like hundreds and thousands of observations, don't you think?


Title: Re: Tonemapping - Plz Halp
Post by: Designerman77 on 2020-05-04, 21:47:37
I don't really appreciate the F-storm vs. Corona Renderer discussion happening on this thread, but this post^ is a really interesting contribution. It sounds like Johannes (unsurprisingly) already did controlled experiments - pretty compelling.
[/quote]


I do not see it as "versus"... but rather "what can we learn from each other and improve the status quo".
Title: Re: Tonemapping - Plz Halp
Post by: romullus on 2020-05-04, 23:03:46
  • I never use contrast < 1.0
  • I never use highlight compression <1.0
  • I never use highlight compression <3.0
  • I never use contrast > 1.0 in combination with a LUT
  • I never use filmic shadows in combination with a LUT
  • I never use LUTS
  • I never use LUTS at an opacity of 1.0
  • I never use the built-in vignetting
  • I never use color tint
  • I never use filmic highlights
  • I always use filmic highlights = 1.0
  • I always use filmic highlights = 1.0 when using a LUT
  • I always use Dubcat ACES emulation
  • I always increase / decrease saturation a little bit
  • I never adjust saturation
  • I never use green-magenta tint
  • I always use sharpening / blurring in the VFB - here are the settings
  • I always keep exposure = 0 and modify light sources instead of EV spinner
  • I never use bloom / glare

False to all.
Title: Re: Tonemapping - Plz Halp
Post by: jms.lwly on 2020-05-04, 23:06:04
In general...
  • I never use contrast < 1.0
  • I never use highlight compression <1.0
  • I never use highlight compression <3.0
  • I never use contrast > 1.0 in combination with a LUT
  • I never use filmic shadows in combination with a LUT
  • I never use LUTS
  • I never use LUTS at an opacity of 1.0
  • I never use the built-in vignetting
  • I never use color tint
  • I never use filmic highlights
  • I always use filmic highlights = 1.0
  • I always use filmic highlights = 1.0 when using a LUT
  • I always use Dubcat ACES emulation
  • I always increase / decrease saturation a little bit
  • I never adjust saturation
  • I never use green-magenta tint
  • I always use sharpening / blurring in the VFB - here are the settings
  • I always keep exposure = 0 and modify light sources instead of EV spinner
  • I never use bloom / glare

This list is exactly the back and forth that I go through during almost every new project - I wish I could decide on a definitive personal favourite - but I can’t. Would love to know everyone else’s approach to all of the above.

Title: Re: Tonemapping - Plz Halp
Post by: lupaz on 2020-05-04, 23:13:14
From the default, I only change exposure trying to keep it as close to zero as possible (I  heard that corona has it easier if that happens), I increase highlight compression to about 2 and contrast to about 3.
I usually don't use LUTs because I do the color adjustments in camera raw in photoshop.

I do use bloom just to soften the aliasing.

Vignetting for some exteriors.





I created this thread with a much more pedestrian goal in mind, basically to ask how others use the tonemapping features. Think of the following as a series of T/F statements, For example:

In general...
  • I never use contrast < 1.0
  • I never use highlight compression <1.0
  • I never use highlight compression <3.0
  • I never use contrast > 1.0 in combination with a LUT
  • I never use filmic shadows in combination with a LUT
  • I never use LUTS
  • I never use LUTS at an opacity of 1.0
  • I never use the built-in vignetting
  • I never use color tint
  • I never use filmic highlights
  • I always use filmic highlights = 1.0
  • I always use filmic highlights = 1.0 when using a LUT
  • I always use Dubcat ACES emulation
  • I always increase / decrease saturation a little bit
  • I never adjust saturation
  • I never use green-magenta tint
  • I always use sharpening / blurring in the VFB - here are the settings
  • I always keep exposure = 0 and modify light sources instead of EV spinner
  • I never use bloom / glare
Title: Re: Tonemapping - Plz Halp
Post by: bluebox on 2020-05-04, 23:14:57
In general...
  • I never use contrast < 1.0
  • I never use highlight compression <1.0
  • I never use highlight compression <3.0
  • I never use contrast > 1.0 in combination with a LUT
  • I never use filmic shadows in combination with a LUT
  • I never use LUTS
  • I never use LUTS at an opacity of 1.0
  • I never use the built-in vignetting
  • I never use color tint
  • I never use filmic highlights
  • I always use filmic highlights = 1.0
  • I always use filmic highlights = 1.0 when using a LUT
  • I always use Dubcat ACES emulation
  • I always increase / decrease saturation a little bit
  • I never adjust saturation
  • I never use green-magenta tint
  • I always use sharpening / blurring in the VFB - here are the settings
  • I always keep exposure = 0 and modify light sources instead of EV spinner
  • I never use bloom / glare

This list is exactly the back and forth that I go through during almost every new project - I wish I could decide on a definitive personal favourite - but I can’t. Would love to know everyone else’s approach to all of the above.



Because you just can't decide.
I mean you can find the tone mapping settings you like and stick to them. But then if you find yourself in a situation that you really need more contrast and crank it up - all of a sudden your shaders will mostly break apart, saturation will go crazy and all this nonsense.

Just tried Fstorm again - have the demo installed but its pain in the @ss on my gtx1060 - contrast does not affect saturation - awesome, reducing burn value does not make the image instantly dull, in fact it does not make the image dull at all - you can even go with negative value - again awesome.

Try for yourself.

Can't really wait what Nvidia shows this year :)
Title: Re: Tonemapping - Plz Halp
Post by: Designerman77 on 2020-05-04, 23:24:16
From the default, I only change exposure trying to keep it as close to zero as possible (I  heard that corona has it easier if that happens), I increase highlight compression to about 2 and contrast to about 3.
I usually don't use LUTs because I do the color adjustments in camera raw in photoshop.

I do use bloom just to soften the aliasing.

Vignetting for some exteriors.



HC generally kills your light dynamics. I try to keep it to 1 and rather use the Filmic Highlights.

One of the Corona devs gave the hint to use the Amland LUTs and leave the Cam settings as basic as possible.
I tried this and it became my new standard.
Works quite nicely.

HC 1
Contrast max. 3
Filmic Highlights 0 - 9
Filmic shadow... better keep it on 0 / max 0.2
Title: Re: Tonemapping - Plz Halp
Post by: cjwidd on 2020-05-04, 23:26:47
@romullus In general though, like 90% of cases - obviously the terms 'never' and 'always' are sort of tautological
Title: Re: Tonemapping - Plz Halp
Post by: lolec on 2020-05-04, 23:44:19
I created this thread with a much more pedestrian goal in mind, basically to ask how others use the tonemapping features. Think of the following as a series of T/F statements, For example:

In general...
  • I never use contrast < 1.0
  • I never use highlight compression <1.0
  • I never use highlight compression <3.0
  • I never use contrast > 1.0 in combination with a LUT
  • I never use filmic shadows in combination with a LUT
  • I never use LUTS
  • I never use LUTS at an opacity of 1.0
  • I never use the built-in vignetting
  • I never use color tint
  • I never use filmic highlights
  • I always use filmic highlights = 1.0
  • I always use filmic highlights = 1.0 when using a LUT
  • I always use Dubcat ACES emulation
  • I always increase / decrease saturation a little bit
  • I never adjust saturation
  • I never use green-magenta tint
  • I always use sharpening / blurring in the VFB - here are the settings
  • I always keep exposure = 0 and modify light sources instead of EV spinner
  • I never use bloom / glare

This is the most interesting thing for me. As this settings are completely different to what I use normally and I actually have NO IDEA on what are the best ones to use.

I edited my scene to use only Corona materials and no copyrighted assets. It means it looks boring but it serves the purpose.

I will post the scene here for anyone to download and try their preferred settings and normal workflow over it.  Please post an image resulting from your workflow as well as your preferred settings. I'll start! This might be very interesting!!

Ok, so this is corona Defaults (only changed EV otherwise its burned up)
(https://i.imgur.com/jL69Duh.jpg)

I never use that as a starting point though. My default settings are this:
(https://i.imgur.com/JYN4TsA.jpg)

I rarely leave it at that though. So My workflow always involves some amount of tweaking. For this particular image, a quick tweaking ends up like this:
(https://i.imgur.com/l8hWYho.jpg)

Not saying that is what I would consider a finished image. But as a quick summary of my normal workflow, and not changing anything about the scene, I would say that's close.

So, If you want to try:

Download the scene from here (created in a student version so none of it can be used for commercial purposes, only learning):https://share.getcloudapp.com/yAu20wZX (https://share.getcloudapp.com/yAu20wZX)
Do not change anything about the scene! Leave light and materials the same, only tweak tonemapping.
Use your usual settings and post the results. It doesn't have to be all inside corona, if you usually take the image outside of corona to finish retouching, go ahead! do that and let's see what a difference workflow makes.






Title: Re: Tonemapping - Plz Halp
Post by: lupaz on 2020-05-04, 23:57:21
Just tried Fstorm again - have the demo installed but its pain in the @ss on my gtx1060 - contrast does not affect saturation - awesome, reducing burn value does not make the image instantly dull, in fact it does not make the image dull at all - you can even go with negative value - again awesome.


This is true. I wish corona at least behaved as a real camera and I could take the rendering from corona as pure raw and do a camera raw in photoshop. I still couldn't figure how to do this.
Title: Re: Tonemapping - Plz Halp
Post by: agentdark45 on 2020-05-05, 02:10:56
If it wasn't a typical Fstorm render, wouldn't you say you would have been able to notice?

Not only you didn't immediately notice but you even complained about the same things you are complaining about corona. And not only you, so maybe there is something else to it than objective observation.

Not sure why you label it as "tricked"  we are talking about comparisons and every serious study requires the elimination of variables.

I'm sorry you didn't like the results of the experiment, I bet that if the result was different and you actually noticed, you would have felt really good about that fact, and confirm your previous notions. So I think just because you didn't get the expected result, there is no reason to say "I did something to the Fstorm version".

Yeah, I'm not buying this. You're saying you went through the effort of purchasing a full Fstorm license, matching the watermark 1:1 in photoshop, and your "swapped" Fstorm render just happens to exhibit exactly the same grain pattern and concrete microdetail as your previous tests...
Title: Re: Tonemapping - Plz Halp
Post by: Juraj on 2020-05-05, 02:19:10
Quote
contrast does not affect saturation

This one is bit unfair, Corona's Contrast is identical to Adobe's, it's basic contrast. It's not mistake that it doesn't operate on luminosity channel only, or offers selective smart saturation (Vibrance).
Some raw editors replaced Saturation with Vibrance (and call it Saturation again), but since we already have saturation, I would just add vibrance. The saturation is the weirdly integrated feature.. doesn't act like anything I know (affects luminosity&contrast way too much).

This is true. I wish corona at least behaved as a real camera and I could take the rendering from corona as pure raw and do a camera raw in photoshop. I still couldn't figure how to do this.

When people say they want Corona to behave like "camera", they actually want it to behave like raw converter. SOOC Jpegs from Camera are done by their own internal raw converter. The raw file itself is linear.

Corona's linear is also "raw", just 32bit floating point raw with massive dynamic range, which needs tonemapping. Even photos when merged into higher dynamic range require tonemapping, you can't just open them in Lightroom or CapturePro and use the base
Most raw converters don't allow these format at all, or they don't work correctly with them.

I once proposed devs what I consider could work as workaround. To allow Corona to save directly into .dng format. Adobe's DNG has both 16bit and 32bit floating point options. And I thought perhaps this would confuse raw editors less, effectively "trick" them.

But even right now it sort of "works". When you use "Open as" in Photoshop, you can open linear floating point (either 16bit or 32bit .exr/.hdr), and you will use absolutely the same workflow ACR would offer you if you loaded merged HDR photo. But you have to use the older process, or accept the odd behavior it can exhibit.
(I didn't test one more theory, if artificially clamping dynamic range before would make ACR more predictable).

The only thing Corona devs can do, is integrate different tonemapping curve (global tonemapper are always just curves). But it does work like camera, and you can export raw.


Whether Lolec is trolling or saying truth, it's genius post :- ).
Title: Re: Tonemapping - Plz Halp
Post by: lolec on 2020-05-05, 03:05:27
Yeah, I'm not buying this. You're saying you went through the effort of purchasing a full Fstorm license, matching the watermark 1:1 in photoshop, and your "swapped" Fstorm render just happens to exhibit exactly the same grain pattern and concrete microdetail as your previous tests...

No, that would be silly!

I rendered a gray box in front of the Fstorm camera to get the raw watermark pattern. I then adjusted the brightness and used color burn to essentially revert what Fstorm is doing. I needed 3 layers to achieve that, as the shadow areas didn't quite work the same as the light areas.  Then I used that same "raw" Fstorm pattern and overlayed it to the Corona render version.

Here is a video of me turning on layers in photoshop :)  https://share.getcloudapp.com/WnuGqzoO (https://share.getcloudapp.com/WnuGqzoO)

You can download the original image I posted and zoom in to see how much of a terrible job I did! (https://i.imgur.com/SjeKjtJ.png)

I know it can be hard to be confronted with information you don't like. But I have nothing to gain out of convincing anyone that Corona is better or worst, I'm a corona user! I want corona to be the best possible render engine! Actually, corona render is my main source of income now that I think of it... so NO I don't want it to stop improving!  BUT! I think it can improve more drastically by being easier to use and easier to achieve it's potential, than to extend it's potential even further. LETS DO BOTH, but lets do the easy one first!


Title: Re: Tonemapping - Plz Halp
Post by: bluebox on 2020-05-05, 09:40:18
Quote
contrast does not affect saturation

This one is bit unfair, Corona's Contrast is identical to Adobe's, it's basic contrast. It's not mistake that it doesn't operate on luminosity channel only, or offers selective smart saturation (Vibrance).
Some raw editors replaced Saturation with Vibrance (and call it Saturation again), but since we already have saturation, I would just add vibrance. The saturation is the weirdly integrated feature.. doesn't act like anything I know (affects luminosity&contrast way too much).


How is this unfair Juraj ? I converted a simple Corona playground scene of mine and when boosting contrast to 5 out of normall 1 my wood shaders started a new after psychedelic like life. They went to the moon with saturation. When doing the same in Fstorm the image remains visually 90% the same, only gets punchier.

I know you optimize your workflow and for sure you have some sort of a shader library of your own. This works great. Lets you streamline your workflow and become super efficient especially when incorporating triplanar wherever possible.
Only problem is that if you prepare your shaders in a controlled dedicated scene (say contrast 1) and then bring them to a more contrasty scene all of a sudden the colours break apart. This should not be the case.

Now, whether you call it saturation, vibrance or other is not important. If we get both controlls- contrast and saturation, imho contrast should operate only on luminosity, saturation should be saturation. And even saturation here does not work as it should - it shifts hue.

I agree that people wanting magicall "make dis shiet photoreal" button will get dissapointed because it will not happen as this comes from a lot of variables - working with references, matching colours etc. but lets just make the tools that we have work as they should. and upgrade the ones that are just bad at the moment - like HC, contrast, etc.
Title: Re: Tonemapping - Plz Halp
Post by: cjwidd on 2020-05-05, 10:05:52
Pretty curious how much of this conversation will even be relevant if the tonemapping options get overhauled for an upcoming version. Presumably we wouldn't be talking about contrast, highlight compression, etc. in the same way.
Title: Re: Tonemapping - Plz Halp
Post by: Juraj on 2020-05-05, 10:45:11
Because Corona Contrast is not part of tonemapping, it's grading tool and works correctly. Contrast 5 means 5 100 contrast modifiers in Photoshop.

It works the same in Photoshop, Lightroom & ACR.

VFB right now has small subset of post tools and ugly tonrmapper. That doesnt mean those post tools are wrong.
We dont need to copy every arbitrary decision someone else did.

Tool names are important, so yes ut matters how we call them. Contrast has nithing to do with anyones toxic looking shaders.
Title: Re: Tonemapping - Plz Halp
Post by: MattiasD on 2020-05-05, 11:25:50
I really like these discussions. It`s maybe not always that constructive or correct, but it does always learn me new things.

@Juraj Talcik: Could you explain how to convert a linear (not tonemapped) image with aces? I downloaded OpenColorIO and Aces and tried to use this in photoshop, but I`m not sure what input and output i should choose from al the options and not even sure i should use photoshop at all for this :).

@lolec:
Here is my take on the scene:
Lut: Filmic Very High Contrast (log color space)
(https://i.imgur.com/S9d3qSs.jpg)
Title: Re: Tonemapping - Plz Halp
Post by: James Vella on 2020-05-05, 12:02:19
lol funny little trick you did there @lolec, and thanks for posting the scene it is an interesting challenge. I gave it a try in Vray keeping everything the same, textures, lighting, ev etc only swapped the camera for a physical but settings are same. Settings were as follows, default Vray, Vray + LUT Canon 300C, Vray/Aces. I think the LUT is actually pretty close to the Aces result but less range in the top end.
I think for Vray using the exposure control gives you a better result at EV 0 but for now we can ignore that.

Vray

(https://i.ibb.co/5LcFqzr/vray1.jpg)
(https://i.ibb.co/VJ1QVXS/vray2.jpg)
(https://i.ibb.co/FYwF0Mn/vray3.jpg)

Vray + LUT Canon 300C
(https://i.ibb.co/VtTWkgx/lut1.jpg)
(https://i.ibb.co/c6JP7Fn/lut2.jpg)
(https://i.ibb.co/ZBYKhN2/lut3.jpg)

Vray/Aces

(https://i.ibb.co/qkhfqM9/aces1.jpg)
(https://i.ibb.co/PhhdsQL/aces2.jpg)
(https://i.ibb.co/vVnF8D9/aces3.jpg)
(https://i.ibb.co/WPGnd8w/aces4.jpg)
(https://i.ibb.co/tmtb76S/aces5.jpg)
(https://i.ibb.co/f2VqbC3/aces6.jpg)

LUT here:
https://cpn.canon-europe.com/content/news/canon_log_luts_now_available.do
BT709_CanonLog2-to-BT709_WideDR_65_FF_Ver.2.0.cube
Title: Re: Tonemapping - Plz Halp
Post by: Fluss on 2020-05-05, 12:08:32
James, did you convert your color textures / internal lights to ACEScg before rendering? If not your results are wrong. You need to put lin_srgb as the input (won't change that much except correcting color shifting)
Title: Re: Tonemapping - Plz Halp
Post by: James Vella on 2020-05-05, 12:15:32
Yes you are correct Fluss. Textures are converted to aces cg space before rendering.

(https://i.ibb.co/DpmyfZ5/tex.jpg)
Title: Re: Tonemapping - Plz Halp
Post by: cjwidd on 2020-05-05, 12:37:35
@James Vella your post indicates the BT709_CanonLog2-to-BT709_WideDR_65_FF_Ver.2.0.cube LUT, but when I downloaded the LUT resources from the provided link, there are dozens of LUTS included. Why did you choose the BT709_CanonLog2-to-BT709_WideDR_65_FF_Ver.2.0 version?
Title: Re: Tonemapping - Plz Halp
Post by: James Vella on 2020-05-05, 12:41:50
\canon-lut-201911\3dlut\65grid-3dlut\full-to-full-range\BT709_CanonLog2-to-BT709_WideDR_65_FF_Ver.2.0.cube

It doesnt give me the same result in Corona as Vray however.

edit (sorry I missed part of your question):
I chose it because there is only 3 to choose from as I need a log to rec709 df65 to match the setup of the corona scene. (6500kelvin).
- BT709_CanonLog2-to-BT709_WideDR_65_FF_Ver.2.0.cube
- BT709_CanonLog3-to-BT709_WideDR_65_FF_Ver.2.0.cube
- BT709_CanonLog-to-BT709_WideDR_65_FF_Ver.2.0.cube

The first one didnt have a vignette, so used that to keep things as clear as possible without adding additional parameters. Its how I work normally with the VFB, the more you play with the tone mapping controls (highlight burn, contrast etc) the more you complicate things when trying to compare results.






Title: Re: Tonemapping - Plz Halp
Post by: Fluss on 2020-05-05, 12:52:47
Yes you are correct Fluss. Textures are converted to aces cg space before rendering.

(https://i.ibb.co/DpmyfZ5/tex.jpg)

And the sun and sky (internal Vray colorspace)?
Title: Re: Tonemapping - Plz Halp
Post by: agentdark45 on 2020-05-05, 13:00:39

Here is a video of me turning on layers in photoshop :)  https://share.getcloudapp.com/WnuGqzoO (https://share.getcloudapp.com/WnuGqzoO)

You can download the original image I posted and zoom in to see how much of a terrible job I did! [img width=1024 height=1187]https://i.imgur.com/SjeKjtJ.png/img]

I know it can be hard to be confronted with information you don't like. But I have nothing to gain out of convincing anyone that Corona is better or worst, I'm a corona user! I want corona to be the best possible render engine! Actually, corona render is my main source of income now that I think of it... so NO I don't want it to stop improving!  BUT! I think it can improve more drastically by being easier to use and easier to achieve it's potential, than to extend it's potential even further. LETS DO BOTH, but lets do the easy one first!

Haha fair play, I'll concede that I was indeed duped by this.
Title: Re: Tonemapping - Plz Halp
Post by: James Vella on 2020-05-05, 13:12:46
Yes you are correct Fluss. Textures are converted to aces cg space before rendering.

(https://i.ibb.co/DpmyfZ5/tex.jpg)

And the sun and sky (internal Vray colorspace)?

Using Raw to AcesCG (but it doesnt make any difference in this example)

(https://i.ibb.co/Ptw8m9r/sunsky.jpg)
Title: Re: Tonemapping - Plz Halp
Post by: Fluss on 2020-05-05, 13:17:31
For the sun and sky you do not need OCIO nodes, you need to change the Vray internal colorspace and it's only accessible by script.

Execute this in the maxscript listener :

Code: [Select]
renderers.current.options_rgbColorSpace = 2
If you don't do this, you are rendering ACEScg textures with sRGB sun and sky
Title: Re: Tonemapping - Plz Halp
Post by: James Vella on 2020-05-05, 13:18:11
For the sun and sky you do not need OCIO nodes, you need to change the Vray internal colorspace and it's only accessible by script.

Execute this in the maxscript listener :

Code: [Select]
renderers.current.options_rgbColorSpace = 2

Thanks! Ill give it a shot
Title: Re: Tonemapping - Plz Halp
Post by: James Vella on 2020-05-05, 13:24:20
Great tip thanks - its not true what they say about you Fluss ;) (jk), fixes the blue color cast.

(https://i.ibb.co/PTkb7Ww/aces-lightfix.jpg)
Title: Re: Tonemapping - Plz Halp
Post by: Fluss on 2020-05-05, 13:33:48
Glad it helped. I'm testing Vray 5 beta and this will be easier!

(https://cdn.discordapp.com/attachments/553458719971868673/706497671560691743/unknown.png)
Title: Re: Tonemapping - Plz Halp
Post by: James Vella on 2020-05-05, 13:44:52
Glad it helped. I'm testing Vray 5 beta and this will be easier!

(https://cdn.discordapp.com/attachments/553458719971868673/706497671560691743/unknown.png)


This checkbox "auto RGB primaries etc..."

This does the utility rgb - acescg conversion for vraybitmaps without needing the OCIO node?
Title: Re: Tonemapping - Plz Halp
Post by: Fluss on 2020-05-05, 13:49:12
Exactly! And it's way quicker than the OCIO conversion. It's based on the filename tho, so you'll still have some work to do.
Title: Re: Tonemapping - Plz Halp
Post by: James Vella on 2020-05-05, 13:52:19
Seems like there could be a better way. Using the tag inside the VrayHDRI for sRGB or Linear. Anyway Ill stop derailing this thread with minor topics.

Title: Re: Tonemapping - Plz Halp
Post by: Fluss on 2020-05-05, 13:55:09
Seems like there could be a better way. Using the tag inside the VrayHDRI for sRGB or Linear. Anyway Ill stop derailing this thread with minor topics.

It's also planned
Title: Re: Tonemapping - Plz Halp
Post by: James Vella on 2020-05-05, 14:33:30
Test #2 with Fstorm.

For this section I kept tonemapping OFF, just to see the results of purely increasing the exposure (keep your eye on the exposure setting).

(https://i.ibb.co/SJ1zJyp/fstorm1.jpg)
(https://i.ibb.co/5TLSpYC/fstorm2.jpg)
(https://i.ibb.co/LNhvVTf/fstorm3.jpg)
(https://i.ibb.co/dkYwzty/fstorm4.jpg)
(https://i.ibb.co/1LbS9tf/fstorm5.jpg)
(https://i.ibb.co/RD1zd38/fstorm6.jpg)

Now we reached the point of blow out. This is where it gets interesting. I turn tonemapping on (defaults)

(https://i.ibb.co/dQGDgyq/fstorm7.jpg)

Now decreasing the burn below 0 (which I expected not good results, but its actually ok). Not sure what to make of it to be honest.

(https://i.ibb.co/ZgTM1YG/fstorm8.jpg)

Title: Re: Tonemapping - Plz Halp
Post by: James Vella on 2020-05-05, 15:00:57
The way I look at it is, color space makes the difference in terms of lighting - its obvious when comparing default Vray with Aces Vray - both have default settings just adjusting exposure value (no tone mapping).

We can then see Fstorm renders without tone mapping, and the light behaves differently to exposure than say default corona/vray. Tone mapping is the last piece of the puzzle here - important yes but not as important as getting a 'photo real' result - might as well use a composite software if you arent happy with the tone mapping controls (not saying it shouldnt be improved but just saying its not going to make a world of difference which you use once you have the correct rendered result).

As others have noted about small details, bumps, materials etc these all help with the bigger picture. My 2c
Title: Re: Tonemapping - Plz Halp
Post by: lupaz on 2020-05-05, 15:06:17
I once proposed devs what I consider could work as workaround. To allow Corona to save directly into .dng format. Adobe's DNG has both 16bit and 32bit floating point options. And I thought perhaps this would confuse raw editors less, effectively "trick" them.

This would be great! Honestly, I think if we could treat Corona as a camera (with the .dng format) and use any post production tool we choose, the tone mapping conversation would get much easier to follow and understand.

Title: Re: Tonemapping - Plz Halp
Post by: lupaz on 2020-05-05, 15:13:54

Download the scene from here (created in a student version so none of it can be used for commercial purposes, only learning):https://share.getcloudapp.com/yAu20wZX (https://share.getcloudapp.com/yAu20wZX)

It doesn't include the textures? There are only Max files in that zip file.

Edit: I see a problem with this test scene: It uses corona sun and sky. May be we should use an HDRI to make comparisons easier.
Title: Re: Tonemapping - Plz Halp
Post by: lolec on 2020-05-05, 16:29:22
Haha fair play, I'll concede that I was indeed duped by this.

Cool that you took it the right way :)

WOW! thanks for downloading the scene and playing around with it. I think there is a lot we can learn from each other.

My objective was to see other people's Corona workflow, so that's why I used Corona tools exclusively, It wasn't meant to compare different engines.

HDRs are loaded at a different starting position and materials would need to be manually converted, it is not a straightforward process.

However, it is very interesting to see different workflows even within Corona! Hope more of you can download and try the scenes, I will later compile all of the images and see what we can learn about it.
Title: Re: Tonemapping - Plz Halp
Post by: lupaz on 2020-05-05, 18:11:36
Not sure if anyone is still interested in this. If not, let me know.

Below I rendered a test with gray materials. I removed the glass. No DOF still.
I did Fstorm, Corona with cache and Corona brute force.
Corona with PT never cleared the noise, even after over 300 passes.


It seems that Corona with path tracing is closer to Fstorm in terms of depth of shadows than with cache. Probably expected though.
So may be if we want more depth like with fstorm we need to use path tracing exclusively.

Look at the shadows inside the profile:
(https://i.imgur.com/DyJsGAH.png)

With cache, the shadow inside that tube is not as defined as with brute force and fstorm. I believe this is in part why people think tone mapping is the problem. Because we try to get more contrast but there's just not enough detail to begin with.


Corona Cache:
(https://i.imgur.com/dUc45aW.jpg)



Corona Path Tracing:
(https://i.imgur.com/qp9ujP0.jpg)


Fstorm:
(https://i.imgur.com/I0VvqjW.jpg)
Title: Re: Tonemapping - Plz Halp
Post by: lupaz on 2020-05-05, 18:16:07
What's impressive about Fstorm is that outside you can see all the detail. With Corona is completely blown out.
Title: Re: Tonemapping - Plz Halp
Post by: lolec on 2020-05-05, 18:23:56
Not sure if anyone is still interested in this. If not, let me know.

Below I rendered a test with gray materials. I removed the glass. No DOF still.
I did Fstorm, Corona with cache and Corona brute force.
Corona with PT never cleared the noise, even after over 300 passes.



Can you post your Corona settings?

I find that increasing Highlight Compression would allow you to recover details outside, but others are posting different settings, curious about what settings you are using. 

Also, would you mind downloading the scene I uploaded and try it with the same Corona settings you are using for this ?

Title: Re: Tonemapping - Plz Halp
Post by: moriah on 2020-05-05, 18:27:48
Does Fstorm use GGX? Seems the BRDF is different compared to Corona, as there's more detail in the shadows.
Title: Re: Tonemapping - Plz Halp
Post by: Fluss on 2020-05-05, 18:36:24
Thx for the test James, I'm dubitative with this conclusion tho. A wider colorspace only allows for a slightly better GI (corona already benefit from that). The lighting part you mention in Vray is the consequence of the tone mapping curve embedded in the ACES view transform.

Lupaz is right, the scene needs to use the same lighting (free hdri or constant color) and the same assets (I see the widows suddenly disappeared in the Fstorm scene). For those who are wondering, the textures are from the corona library. Also, matching the initial exposure is important to start on a similar basis imho.

I made a quick test in Vray with this HDRi : https://hdrihaven.com/hdri/?h=reichstag_1
camera : iso 1600 / F-number : 4 / shutter speed : 1/50s

Default sRGB :

(https://forum.corona-renderer.com/index.php?action=dlattach;topic=28156.0;attach=125799;image)

ACES view trasnform with sRGB primaries (so no texture conversion) :

(https://forum.corona-renderer.com/index.php?action=dlattach;topic=28156.0;attach=125801;image)

sRGB + Highlight compression + Handmade curve :

(https://forum.corona-renderer.com/index.php?action=dlattach;topic=28156.0;attach=125803;image)

(https://forum.corona-renderer.com/index.php?action=dlattach;topic=28156.0;attach=125805;image)

It took me 10s to build the curve by hand to my liking and it's really close to what ACES do and I still have control over the curve and the highlight compression.
Title: Re: Tonemapping - Plz Halp
Post by: Fluss on 2020-05-05, 18:46:02
Thx Lupaz, they are pretty close now. I guess tone mapping is activated Fstorm ?
Title: Re: Tonemapping - Plz Halp
Post by: James Vella on 2020-05-05, 18:49:25
Thx for the test James, I'm dubitative with this conclusion tho. A wider colorspace only allows for a slightly better GI (corona already benefit from that). The lighting part you mention in Vray is the consequence of the tone mapping curve embedded in the ACES view transform.

Lupaz is right, the scene needs to use the same lighting (free hdri or constant color) and the same assets (I see the widows suddenly disappeared in the Fstorm scene). For those who are wondering, the textures are from the corona library. Also, matching the initial exposure is important to start on a similar basis imho.

Good to know, ill have to have a play with these settings tomorrow. Cheers!
Title: Re: Tonemapping - Plz Halp
Post by: Fluss on 2020-05-05, 18:55:49
Thx for the test James, I'm dubitative with this conclusion tho. A wider colorspace only allows for a slightly better GI (corona already benefit from that). The lighting part you mention in Vray is the consequence of the tone mapping curve embedded in the ACES view transform.

Lupaz is right, the scene needs to use the same lighting (free hdri or constant color) and the same assets (I see the widows suddenly disappeared in the Fstorm scene). For those who are wondering, the textures are from the corona library. Also, matching the initial exposure is important to start on a similar basis imho.

Good to know, ill have to have a play with these settings tomorrow. Cheers!

I still find ACES a bit better (did not try to match the curve exactly tho) but that was just to show that the differences are not huge.
Title: Re: Tonemapping - Plz Halp
Post by: lupaz on 2020-05-05, 19:09:06
Can you post your Corona settings?

I find that increasing Highlight Compression would allow you to recover details outside, but others are posting different settings, curious about what settings you are using. 

Also, would you mind downloading the scene I uploaded and try it with the same Corona settings you are using for this ?

Yes, definitely with highlight compression I'd start seeing

These were the settings before:
(https://i.imgur.com/D1wiN4p.png)

And this is with highlight compression. The interior starts to get dull.

(https://i.imgur.com/fuzmFml.jpg)

Title: Re: Tonemapping - Plz Halp
Post by: Fluss on 2020-05-05, 19:11:28
Try to make an s-curve like this with corona curves:

(https://forum.corona-renderer.com/index.php?action=dlattach;topic=28156.0;attach=125805;image)

Title: Re: Tonemapping - Plz Halp
Post by: MattiasD on 2020-05-05, 19:19:20
Maybe that`s why a lot of people are asking for ACES implementation. It`s not the holy grail, but you wouldn`t be doing some custom curves, that just look close enough...
It would be amazing if the devs find time to implement it. I personally think it`s just a matter of time, since it`s getting, much like Dontnod`s PBR back in the day, more an industry standard.
And i`d really like to move forward and start complaining about other stuff :)
Title: Re: Tonemapping - Plz Halp
Post by: lolec on 2020-05-05, 19:34:07


Yes, definitely with highlight compression I'd start seeing


I always use HC in combination to contrast ( 3- 4 )  In a way, contrast is similar to making a S curve.
Title: Re: Tonemapping - Plz Halp
Post by: lupaz on 2020-05-05, 19:40:28


Yes, definitely with highlight compression I'd start seeing


I always use HC in combination to contrast ( 3- 4 )  In a way, contrast is similar to making a S curve.

Yup. I do the exact same thing. HC at 2 and contrast at 3 is my default.
Title: Re: Tonemapping - Plz Halp
Post by: Designerman77 on 2020-05-05, 19:58:58
Yup. I do the exact same thing. HC at 2 and contrast at 3 is my default.
[/quote]


HC very quickly starts to eat the light dynamic in images, so they become sizer dull and dark.
I almost never increase HC over 1.1 / 1.2.
Instead you can crank up Filmic Highlights until you see details in overexposed areas, without sacrificing the overall dynamics of your image.

HC 1
Contrast 2-3
Filmic 0-0.9

Works in 99%



Title: Re: Tonemapping - Plz Halp
Post by: lupaz on 2020-05-05, 20:06:47
Yup. I do the exact same thing. HC at 2 and contrast at 3 is my default.


HC very quickly starts to eat the light dynamic in images, so they become sizer dull and dark.
I almost never increase HC over 1.1 / 1.2.
Instead you can crank up Filmic Highlights until you see details in overexposed areas, without sacrificing the overall dynamics of your image.

HC 1
Contrast 2-3
Filmic 0-0.9

Works in 99%
[/quote]

To me, filmic highlights makes everything even duller than HC. I guess it's a matter of taste.
Title: Re: Tonemapping - Plz Halp
Post by: Designerman77 on 2020-05-05, 20:11:32
To me, filmic highlights makes everything even duller than HC. I guess it's a matter of taste.
[/quote]


Oh, that's really interesting.

In C4D / Corona, this behaves exactly the opposite.
I'm still using Corona 4.
Hopefully this HC / Filmic behavior I got used to is not gonna change in Cor. 5...
Title: Re: Tonemapping - Plz Halp
Post by: Designerman77 on 2020-05-05, 20:16:05
Regarding those three test pics ( VRay sRGB / VRay ACES / VRay curves ), in the first moment my eyes went to Vray + curves.
But after short comparison, one realizes that looking at the ACES-pic takes much less effort from your eyes.
This is exactly the effect I notice in renders with lighting / contrasts / colors that feel "right" and "natural".
Title: Re: Tonemapping - Plz Halp
Post by: Fluss on 2020-05-05, 20:44:28
Yes, gradations are way smoother. I think sRGB EOTF  is fucking with light to shadow transition.
Title: Re: Tonemapping - Plz Halp
Post by: cjwidd on 2020-05-05, 21:24:31
I've been using <1.0 HC, as is described in Dubcat's ACES emulation settings, and it *feels* like it brings back dynamic range, i.e. the image looks more punchy, more depth
Title: Re: Tonemapping - Plz Halp
Post by: Designerman77 on 2020-05-05, 22:36:36
I've been using <1.0 HC, as is described in Dubcat's ACES emulation settings, and it *feels* like it brings back dynamic range, i.e. the image looks more punchy, more depth

Pretty cool! Tried it out right now in one of those sh**ty tiny bathroom scenes.
Indeed it punches up that boring, grayish overlay.

It burns the highlights, of course, but even after increasing filmic, one still has enough contrast.

Why haven't I tried this before? :))))


Is there a link to Dubcat´s ACES emulation you mentioned?

Title: Re: Tonemapping - Plz Halp
Post by: Fluss on 2020-05-05, 22:53:43
I've been using <1.0 HC, as is described in Dubcat's ACES emulation settings, and it *feels* like it brings back dynamic range, i.e. the image looks more punchy, more depth

I never tried those settings. I have to admit they sound completely nonsense for me, on paper at least. Maybe the combination with filmic highlight counterbalances the 0.7 HC compression. I'll give it a go tho, as Dubcat always conducted is tests rigorously and always delivered good stuff. Settings are attached for those wondering.
Title: Re: Tonemapping - Plz Halp
Post by: Designerman77 on 2020-05-05, 23:11:39
I've been using <1.0 HC, as is described in Dubcat's ACES emulation settings, and it *feels* like it brings back dynamic range, i.e. the image looks more punchy, more depth

I never tried those settings. I have to admit they sound completely nonsense for me, on paper at least. Maybe the combination with filmic highlight counterbalances the 0.7 HC compression. I'll give it a go tho, as Dubcat always conducted is tests rigorously and always delivered good stuff. Settings are attached for those wondering.


Thanks Fluss! Had just googled it... sorry guys for stupid asking. :)

Have tried those settings. Filmic highlights and filmic shadows on 1... hmmm... makes the image look a flat, as we all know.
But who knows, maybe that's the proper base for an efficient work in post???

We should check it.

However... HC lower than 1 seems to be the magic stick ! :))))))

Thanks, cjwidd !
Now that's what I call a great discussion leading to great sharing of knowledge.
Title: Re: Tonemapping - Plz Halp
Post by: hldemi on 2020-05-05, 23:15:18
I've been using <1.0 HC, as is described in Dubcat's ACES emulation settings, and it *feels* like it brings back dynamic range, i.e. the image looks more punchy, more depth

I never tried those settings. I have to admit they sound completely nonsense for me, on paper at least. Maybe the combination with filmic highlight counterbalances the 0.7 HC compression. I'll give it a go tho, as Dubcat always conducted is tests rigorously and always delivered good stuff. Settings are attached for those wondering.

I have bought this Bertrand Benoit scene ( see attachment ) and many of his cameras have 0.5 HC. This makes them much more realistic.
Title: Re: Tonemapping - Plz Halp
Post by: Designerman77 on 2020-05-05, 23:20:10
I gave it a spin in Photoshop.

I have the impression ( have not double checked I´t yet ) that with Dubcat´s HC 0,6 , even in the shitty 8 bit JPG there was plenty of information in the "lost" highlights,
which could be brought back to life in PS.

Such effect I only know from my Fuji X100 camera which gives out JPGs that behave more like a RAW in post.
Title: Re: Tonemapping - Plz Halp
Post by: Designerman77 on 2020-05-05, 23:21:51
I have bought this Bertrand Benoit scene ( see attachment ) and many of his cameras have 0.5 HC. This makes them much more realistic.
[/quote]


Ahaaaaa ! :)
Now I understand where all that dynamic in many top renders might have come from. At least probably in a certain percentage.
Title: Re: Tonemapping - Plz Halp
Post by: cjwidd on 2020-05-05, 23:26:31
Yeah, just to clarify about the HC < 1.0 suggestion:

There is no algorithmic approach for flmic highlights, in my opinion - by default I leave them at 0.

Dubcat ACES emulation calls for filmic shadows = 1.0 and filmic highlights = 1.0, but in my experience, this does not lead to a desirable look. Moreover, Dubcat has also suggested not using filmic shadows in combination with his filmic LUTs (i.e. wonky contrast), so filmic highlights and filmic shadows seem to be a sort of "season to taste" option, rather than an option I (personally) lean into, as opposed to contrast, or highlight compression, which I adjust strongly.

If anyone has other tips / suggestions like this, I would be happy to hear about them
Title: Re: Tonemapping - Plz Halp
Post by: hldemi on 2020-05-05, 23:27:24
I have bought this Bertrand Benoit scene ( see attachment ) and many of his cameras have 0.5 HC. This makes them much more realistic.


Ahaaaaa ! :)
Now I understand where all that dynamic in many top renders might have come from. At least probably in a certain percentage.
[/quote]

And Bertrand figured it out few years ago. Just compensate with lowering exposure and contrast since going with HC under 1 pushes those parameters up ( not on paper so it might bypass some other bad byproducts of those ). This might be a way to increase contrast without increasing contrast if you get me.
Title: Re: Tonemapping - Plz Halp
Post by: Designerman77 on 2020-05-05, 23:32:37
And Bertrand figured it out few years ago. Just compensate with lowering exposure and contrast since going with HC under 1 pushes those parameters up ( not on paper so it might bypass some other bad byproducts of those ). This might be a way to increase contrast without increasing contrast if you get me.
[/quote]


Yep, how to not understand that? :)
However, I kind of wonder that this is not a standard setting in render engines yet...


I'm working on a job in parallel while reading here and applied those settings to the scene.
Gonna keep that 0.6 / 0.7 HC as standard as often as possible.
Title: Re: Tonemapping - Plz Halp
Post by: lupaz on 2020-05-05, 23:38:10
I have bought this Bertrand Benoit scene ( see attachment ) and many of his cameras have 0.5 HC. This makes them much more realistic.

That's a rather dark image though. Not many clients would accept it like that. What if you had to brighten it up?

Does he use filmic highlight?
Title: Re: Tonemapping - Plz Halp
Post by: cjwidd on 2020-05-05, 23:38:43
@hldemi

FYI, you should begin typing your response outside of the [/quote] snippet for proper formatting
Title: Re: Tonemapping - Plz Halp
Post by: hldemi on 2020-05-05, 23:39:11

Take a look at this also made in Corona ( you probably seen it already)
https://www.behance.net/gallery/42186689/Apoco77-House

What is similar to Bertrands scene is extreme highlight burn from outside ( by going under 1 HC ) . This however gives this dynamic range inside that is IMO worth the trade. And this burn can be bypassed by corona tonemap control texture map.
Title: Re: Tonemapping - Plz Halp
Post by: cjwidd on 2020-05-05, 23:41:09
^this scene seems to be really driven by the materials and the modeling, although the tonemapping is obviously driving home a pretty specific look. Great project, of course, pretty sure it was on the Corona Renderer installer splash screen for a while.
Title: Re: Tonemapping - Plz Halp
Post by: lupaz on 2020-05-05, 23:42:16

I have bought this Bertrand Benoit scene ( see attachment ) and many of his cameras have 0.5 HC. This makes them much more realistic.

I think this would be something that I'd think  a client would accept in terms of overall brightness:
(credit: Danthree.com)

(https://i.imgur.com/GXuwLrF.jpg)

Title: Re: Tonemapping - Plz Halp
Post by: Designerman77 on 2020-05-05, 23:58:33

Take a look at this also made in Corona ( you probably seen it already)
https://www.behance.net/gallery/42186689/Apoco77-House

What is similar to Bertrands scene is extreme highlight burn from outside ( by going under 1 HC ) . This however gives this dynamic range inside that is IMO worth the trade. And this burn can be bypassed by corona tonemap control texture map.



I agree. That's worth the trade!
Such a good base is worth spending some more minutes in post, too in order to get rid of the excessive burning.
Title: Re: Tonemapping - Plz Halp
Post by: James Vella on 2020-05-06, 08:33:04
@Fluss, I gave you settings a go and I found at EV0 you are correct, they look similar. Things start to go pear shaped when you hit -5 +3 (for the sRGB/Highlight Compression). Whats your take on this, I miss something?

Vray HDRI Aces

(https://i.ibb.co/svVKnkp/hdri-aces1.jpg)
(https://i.ibb.co/myp8rNs/hdri-aces2.jpg)
(https://i.ibb.co/BZLjTyz/hdri-aces3.jpg)

Vray HDRI sRGB + Curve/Highlight Compression

(https://i.ibb.co/x8Kb0Jk/hdri1.jpg)
(https://i.ibb.co/yhtj2LR/hdri2.jpg)
(https://i.ibb.co/QmNtJhQ/hdri3.jpg)
Title: Re: Tonemapping - Plz Halp
Post by: Fluss on 2020-05-06, 11:15:22
James, leave the VFB exposure at 0 and increase your render exposure by 3 EVs (so let's say from iso 1600 to iso 12800 in camera settings) and see what happens.

edit:  render exposure was limited by Max Ray intensity.
Title: Re: Tonemapping - Plz Halp
Post by: Fluss on 2020-05-06, 11:47:47
I made it for you:

Vray + curve + HC - ISO 1600 :

(https://forum.corona-renderer.com/index.php?action=dlattach;topic=28156.0;attach=125803;image)

Vray + curve + HC - ISO 12800 :

(https://forum.corona-renderer.com/index.php?action=dlattach;topic=28156.0;attach=125851;image)

edit : 3EVs at render time should match 3EVs in VFB, it does not in Vray (Vray 5 beta here)
Title: Re: Tonemapping - Plz Halp
Post by: Fluss on 2020-05-06, 11:54:22
Now here is the interesting part. Made the same test with Corona - photographic exposure - same settings as Vray.

Corona + curve + HC - ISO 1600

(https://forum.corona-renderer.com/index.php?action=dlattach;topic=28156.0;attach=125871;image)

Corona + curve + HC - ISO 12800

(https://forum.corona-renderer.com/index.php?action=dlattach;topic=28156.0;attach=125869;image)

Title: Re: Tonemapping - Plz Halp
Post by: James Vella on 2020-05-06, 12:44:36
hmm ok I understand what you mean, but this requires re-rendering. As with the ACES workflow you can adjust the exposure and get the range you need without blowing out areas, similar to how you would work with a photograph in lightroom.

Title: Re: Tonemapping - Plz Halp
Post by: Fluss on 2020-05-06, 12:51:14
hmm ok I understand what you mean, but this requires re-rendering. As with the ACES workflow you can adjust the exposure and get the range you need without blowing out areas, similar to how you would work with a photograph in lightroom.

No, this will happen with ACES too. Look at your ACES example, it's also washed out.  Vray and Corona renders are not exposed the same
Title: Re: Tonemapping - Plz Halp
Post by: James Vella on 2020-05-06, 13:13:37
This is probably a terrible example as I dont do indoor photography (and the snow doesnt help) but this is almost the same expectation of results that I got with the aces test. Exposure stops, -5, -2, 0, +3, +5

(https://i.ibb.co/tzXwwY5/foto1.jpg)
(https://i.ibb.co/bQ63ySw/foto2.jpg)
(https://i.ibb.co/nwPPt4s/foto3.jpg)
(https://i.ibb.co/tHYfXxh/foto4.jpg)
(https://i.ibb.co/kqq4sj6/foto5.jpg)





Title: Re: Tonemapping - Plz Halp
Post by: Fluss on 2020-05-06, 14:32:52
Here is what we will consider default exposure for this comparison :

Vray - ACES TM - ISO1600

(https://forum.corona-renderer.com/index.php?action=dlattach;topic=28156.0;attach=125881;image)

Now, which of those two renders do you consider correct? Corona is correct

Vray - ACES TM - ISO1600 - +3EV VFB

(https://forum.corona-renderer.com/index.php?action=dlattach;topic=28156.0;attach=125883;image)

Vray - ACES TM - ISO12800 (+3EV rendering) - +0EV VFB

(https://forum.corona-renderer.com/index.php?action=dlattach;topic=28156.0;attach=125885;image)

I personally made my choice.

edit : after some more thoughts, removed some too early conclusions
edit2 : here is what has been removed. Decided to finally keep it to open the discussion, might be false assumptions :

Now if you look at corona 12800 ISO, it looks like it is not calculating real scene exposure but a base exposure which is then multiplied (like the results we get by increasing exposure in VFB). I'm not really sure what is happening here but that could be an explanation.
-> Vray exposure is limited by max ray intensity


Corona - CURVE + 8HC 12800ISO

(https://forum.corona-renderer.com/index.php?action=dlattach;topic=28156.0;attach=125887;image)

Title: Re: Tonemapping - Plz Halp
Post by: James Vella on 2020-05-06, 15:48:52
hmm, neither do to be honest.

I just took a photo of a room in the house as a raw photo and took it into lightroom:

Exposure: 0
(https://i.ibb.co/px1rVdj/room1.jpg)

Exposure: 1.5
(https://i.ibb.co/fSs9pYM/room2.jpg)

Exposure: 3.0
(https://i.ibb.co/zNP1Mwv/room3.jpg)

The problem Im seeing is the light behaviour is actually quite similar to the fstorm render tests a couple pages back (potentially the default bloom was effecting the result). Where as I see the highlight areas in these last renders as dull in comparison.

I think your last Corona render is probably the best of all 3. I find this quite interesting, ill have to think about this a bit more for awhile.
Title: Re: Tonemapping - Plz Halp
Post by: Fluss on 2020-05-06, 16:23:03
Of course it's dull, we're using ACES to compress highlights like crazy. Adding some quick crazy bloom and glare help. Still, there is something strange with the corona exposure in my opinion. ->it's good

(https://forum.corona-renderer.com/index.php?action=dlattach;topic=28156.0;attach=125894;image)


Title: Re: Tonemapping - Plz Halp
Post by: Fluss on 2020-05-06, 22:16:25
Well, always though Vray and corona photographic exposure settings would match but after quickly looking at it a bit closer, it does not seems to be the case. I'll try to dig a bit further if I find time. The corona one seems to make more sense at first sight.

edit: confirmed, Vray exposure is wrong limited by MRI, corona is good. So pointless comparison from the start between corona and Vray, forget my posts

Guys, checking the technical side is crucial in those kinds of comparisons, so as explaining the process... Everybody was taking a conclusion on renders with different lighting.... That sucks.

If you are looking for me, I'm hiding. 😂
Title: Re: Tonemapping - Plz Halp
Post by: lupaz on 2020-05-06, 23:05:20
Is it even possible to match every technical aspect between render engines anyway?
Title: Re: Tonemapping - Plz Halp
Post by: cjwidd on 2020-05-06, 23:15:07
@lupaz definitely not, but emerging color standards are helping to increase parity between different renderers

Title: Re: Tonemapping - Plz Halp
Post by: cjwidd on 2020-05-06, 23:16:19
Cross-posting a thread about calculating Corona EV from 'I need help (https://forum.corona-renderer.com/index.php?board=29.0)' because it's relevant to the current discussion:

EV vs. Corona EV (https://forum.corona-renderer.com/index.php?topic=28968.0)
Title: Re: Tonemapping - Plz Halp
Post by: Fluss on 2020-05-06, 23:25:20
For such trivial things as exposure, I expected it to be more or less the same. The thing is that if I raise my ISO from 1600 to 12800 ISO, I should have +3EV.
In corona, a render at  1600ISO, +3EV in post looks more or less the same as a render at 12800 ISO. In Vray, at least in V5 beta, it's not the case.
-> In Vray, I was limited by Max sample intensity.
Title: Re: Tonemapping - Plz Halp
Post by: James Vella on 2020-05-07, 07:24:38
Is it even possible to match every technical aspect between render engines anyway?

@lupaz I dont think so, nor is it entirely important - what I find important is parity between materials. You should be able to change lighting based on preference and if the materials are setup correctly (PBR for example) then you know you can adjust the lighting/tonemapping to taste without borking something else along the line.

Well, always though Vray and corona photographic exposure settings would match but after quickly looking at it a bit closer, it does not seems to be the case. I'll try to dig a bit further if I find time.

@Fluss I think your first thought was correct, so you are not going crazy :) I found that with some testing this morning 1600 - 12800 is exactly 3 stops. Thanks to @cjwidd and @maru for posting the thread on the vs EV thread I was able to use the excel sheet to do the conversion and it seems correct to me.

Vray 1600 ISO / 0 Exposure

(https://i.ibb.co/f19rWRM/iso-vray1600-0exp.jpg)

Vray 1600 ISO / +3 Exposure

(https://i.ibb.co/2qBpLx5/iso-vray1600-3exp.jpg)

Vray 12800 ISO / 0 Exposure

(https://i.ibb.co/0sD6LT7/iso-vray12800-0exp.jpg)

Corona 1600 ISO / 0 Exposure

(https://i.ibb.co/k0F01Kv/corona1600-0exp.jpg)

Corona 1600 ISO / +3 Exposure

(https://i.ibb.co/xFN8CGh/corona1600-3exp.jpg)

Corona 12800 ISO / 0 Exposure

(https://i.ibb.co/pw3gHSx/corona12800-0exp.jpg)

Just an FYI if you are trying to follow along in Corona, I had to switch this to a Physical Camera as the Corona Camera was giving me strange results. Not entirely sure why - maybe its just because I always use Physical Camera for vray/corona and used to the setup.

edit:
My conclusion is that I still think the ACES workflow is producing the result that is most similar to photographic workflow (lightroom). Where if you have a well exposed image with no crushed areas then you should be able to push the light either way without compromising your highlights somewhere (actually more so since we are working in 32bit float). Similar to how you can blow out the fstorm render and then pull it back with the burn setting, this is impossible with Corona's highlight compression.
Title: Re: Tonemapping - Plz Halp
Post by: Fluss on 2020-05-07, 07:40:38
I was using renderer's native camera in both. We're definitely experiencing different results here.
Title: Re: Tonemapping - Plz Halp
Post by: James Vella on 2020-05-07, 08:05:12
Yes it took me a few moments to work out how to get parity between them at 1600 / 0 Exposure, thats because there was some limitations with the Physical Camera. My mistake, I used Vray Camera for Vray, Physical Camera for Corona (as I had issues with the Corona Camera overriding my global settings).

This should get you off on the right foot for the comparison.

Vray Settings (Vray Camera):

(https://i.ibb.co/rmBhgDR/vraysettings.jpg)

Corona Settings (Physical Camera):

(https://i.ibb.co/Mh4sby6/coronasettings.jpg)

3D Files (3dsmax 2019):

https://we.tl/t-K37vLOCyk0

For this setup I had to change the fstop (16) shutter speed (2000) for a good base point for adjusting the exposure 3 stops. This way you should have both on parity from this point onwards. Based on the excel document in Corona thats -2.813 for +3 exposure, and -5.813 for 0 exposure. Vray you just adjust the exposure without any need for a conversion.
Title: Re: Tonemapping - Plz Halp
Post by: Fluss on 2020-05-07, 08:46:31
I downloaded your scene and it worked as expected. But if you try with my camera settings (f4, 1/50s, 1600/12800) and load the HDRi I used for the test (Vraymap, spherical mapping, everything else default), it doesn't work anymore. really strange. Is it the case on your side? (Also, no tone mapping, standard sRGB display)
(Note that with this setup, we're closer to image burn)


Title: Re: Tonemapping - Plz Halp
Post by: Fluss on 2020-05-07, 08:56:25
Found out that max ray intensity was the "culprit" in Vray. Disabling it solved the issue. I edit my previous messages, it's kind of a mess. Maybe it would be better to delete them
Title: Re: Tonemapping - Plz Halp
Post by: James Vella on 2020-05-07, 09:32:32
Found out that max ray intensity was the culprit in Vray. Disabling it solved the issue.

Yep, that did the trick!
Title: Re: Tonemapping - Plz Halp
Post by: Fluss on 2020-05-07, 09:43:59
This makes me think the more "directional look" of Fstorm is due to heavy GI clamping.
Title: Re: Tonemapping - Plz Halp
Post by: Fluss on 2020-05-07, 11:00:23
Reinstalled Fstorm,  and damn! I don't like it! I forgot how it feels, well, completely different. In a bad way. It seems the glossiness is indeed still mapped from 0.4 to 1.0.
Title: Re: Tonemapping - Plz Halp
Post by: James Vella on 2020-05-07, 12:25:38
deleted, reinstalled Fstorm,  and damn! I don't like it! I forgot how it feels, well, completely different. In a bad way. It seems the glossiness is indeed still mapped from 0.4 to 1.0.

Takes a few moments to work some things out. I really like how simple it is, just be aware all bitmaps come in at the correct gamma no need to change anything except HDRI's should be set to 2.2 (kind of opposite but first time user friendly in a way, same goes for render settings in tone mapping leave the gamma settings alone). One thing that I find difficult is there is no camera settings like shutter speed, fstop doesnt affect the lighting like a camera does (that I have found yet, I dont really use it either to be honest just tests every now and then). This will also affect these tests since we cant really bench it against each other. Exposure seems to be a bit arbitrary (or I havent found the recipe for it). But I think this is the charm of it, you dont need to be a technician to use it, you just adjust the exposure/tone mapping and the rest is taken care of without much thought - which is kind of where I see this conversation going, people want an out of the box photo real experience, not having to think about gamma settings or camera settings and get the photo real result. Technical people will probably have a melt down at first but theres probably more to it that Im unaware of, just going by what I read of peoples blog posts etc.
Title: Re: Tonemapping - Plz Halp
Post by: Fluss on 2020-05-07, 12:29:01
TBH I'm fed up with those comparisons.. I'm gonna stop there, the more I dig into it, the more I feel it pointless... I always come to the same conclusion, a renderer is a tool, and if used wisely, you can produce beautiful results with any of them.
Title: Re: Tonemapping - Plz Halp
Post by: James Vella on 2020-05-07, 12:56:24
lol thats fair enough, thanks for chiming in its been an interesting experiment.

... I always come to the same conclusion, a renderer is a tool, and if used wisely, you can produce beautiful results with any of them.

I completely agree with you.

For the experiments I posted above, I was interested in keeping focus on just one variable - exposure, and disregarding tone mapping entirely for the sake of trying to single out of this variable has any effect on the flexibility of the lighting control from the artists perspective after rendering. From this point onwards introducing one additional variable - highlight compression, and what I expect to be able to control once I have my rendered image with tone mapping.

I once proposed devs what I consider could work as workaround. To allow Corona to save directly into .dng format. Adobe's DNG has both 16bit and 32bit floating point options. And I thought perhaps this would confuse raw editors less, effectively "trick" them.

I think Juraj is on to something here. For people in the archviz field this would be a great option.

For those who work in film, they already work in 32bit space with linear images and thus have a solid pipeline for post production corrections.

Speaking on behalf of myself (and assuming others in this thread), we want that same control in our VFB, we want to render like photographers. Which is why I think fstorm is toted as having excellent tone mapping controls.

edit:
Instead of rendering like a photographer, what I mean to say is render as the human eye perceives things.
Title: Re: Tonemapping - Plz Halp
Post by: Designerman77 on 2020-05-07, 15:13:09
TBH I'm fed up with those comparisons.. I'm gonna stop there, the more I dig into it, the more I feel it pointless... I always come to the same conclusion, a renderer is a tool, and if used wisely, you can produce beautiful results with any of them.

Not with "any of them". Otherwise there would not be different render engines on the market.

Before I chose Corona as an renderer, I compared ( I guess ) hundreds of images from the net, coming from Octane, VRay, Arnold, etc. etc.
One could clearly see differences. Guess which difference was the most obvious to me? Lighting & color grading!

Some render engines create (in average) more artificial images than others. Corona was and is among the top three engines that have beautiful, realistic lighting and especially a pleasant atmosphere in images.

But as with everything in life, everything is great until you see something greater.
And sorry to say... but from FStorm I see images from at user levels - and it is immediately visible that the engine has a more photoreal way to calculate light, contrasts and colors.
We can make 1 Mio. tests here with trivial little chambers and a ball in the background. :))))







Title: Re: Tonemapping - Plz Halp
Post by: Designerman77 on 2020-05-07, 15:23:01

edit:
Instead of rendering like a photographer, what I mean to say is render as the human eye perceives things.
[/quote]



Yes, bud... that's exactly what I suggested at the beginning of this long discussion.
Make only two modes: 1. behavior like a DSLR.   2. Behavior like a human eye (more less).

When we look at our natural surrounding, we rarely see burnt highlights, black shadows, etc... only in very extreme sunlight situations.
That's because our iris and the brain constantly compensate light dynamic changes in milliseconds.

We are in 2020. It shouldn't be impossible to write two codes that mimic a cam and an eye 99% correctly, instead of making 3D artist fiddle with curves.
Title: Re: Tonemapping - Plz Halp
Post by: Fluss on 2020-05-07, 15:45:20
We are in 2020. It shouldn't be impossible to write two codes that mimic a cam and an eye 99% correctly, instead of making 3D artist fiddle with curves.

I give you 2hrs, show me :) Just hope you manage to teleport a display capable of human eye dynamic range from 22th century.
Title: Re: Tonemapping - Plz Halp
Post by: lolec on 2020-05-07, 16:10:43
We are in 2020. It shouldn't be impossible to write two codes that mimic a cam and an eye 99% correctly, instead of making 3D artist fiddle with curves.

DSLR already try to approximate what our eyes see. That should be achievable.

But achieving 99% of what the eye sees is literally impossible with current tech and understanding of the world. We don’t “see” in the same sense a camera does, our brain builds an illusion and we make sense of it in our memory.

I’m curios what reference do you hace of renders or images that in your opinion represent what the eye can see?

Again, DSLR try to achieve that, so I’m not sure what is the difference between the two thibgs you are asking
Title: Re: Tonemapping - Plz Halp
Post by: dfcorona on 2020-05-07, 17:10:24

edit:
Instead of rendering like a photographer, what I mean to say is render as the human eye perceives things.




Yes, bud... that's exactly what I suggested at the beginning of this long discussion.
Make only two modes: 1. behavior like a DSLR.   2. Behavior like a human eye (more less).

When we look at our natural surrounding, we rarely see burnt highlights, black shadows, etc... only in very extreme sunlight situations.
That's because our iris and the brain constantly compensate light dynamic changes in milliseconds.

We are in 2020. It shouldn't be impossible to write two codes that mimic a cam and an eye 99% correctly, instead of making 3D artist fiddle with curves.
That's hilarious, I suggested such a thing years ago to Vlado with vray.  I even called it Vrayphysicaleye instead of camera.  I know the name is a little goofy, and everyone laughed at my idea.
Title: Re: Tonemapping - Plz Halp
Post by: Designerman77 on 2020-05-07, 17:13:38
We are in 2020. It shouldn't be impossible to write two codes that mimic a cam and an eye 99% correctly, instead of making 3D artist fiddle with curves.

I give you 2hrs, show me :) Just hope you manage to teleport a display capable of human eye dynamic range from 22th century.


I'm neither a programmer nor do I have a PHD in optical physics. :) Give me 4 hours, please. :)))
Title: Re: Tonemapping - Plz Halp
Post by: maru on 2020-05-07, 17:25:38
If we are to develop a renderer, which simulates what the human eye can see, we should also develop a monitor, which can display such data. Please give us at least 5 hours.
Title: Re: Tonemapping - Plz Halp
Post by: vlado on 2020-05-07, 17:26:50
And sorry to say... but from FStorm I see images from at user levels - and it is immediately visible that the engine has a more photoreal way to calculate light, contrasts and colors.
I'm sure I will regret jumping into this thread, but I feel I have to say this. No, it's not "photoreal". There is no real-world photographic camera that can produce those results. They are very nice images for sure and it's fine if people prefer them (even though they always feel a little off and too cold to me) but they are not "photorealistic".

Best regards,
Vlado
(hiding for cover)
Title: Re: Tonemapping - Plz Halp
Post by: dfcorona on 2020-05-07, 17:32:49
And sorry to say... but from FStorm I see images from at user levels - and it is immediately visible that the engine has a more photoreal way to calculate light, contrasts and colors.
I'm sure I will regret jumping into this thread, but I feel I have to say this. No, it's not "photoreal". There is no real-world photographic camera that can produce those results. They are very nice images for sure and it's fine if people prefer them (even though they always feel a little off and too cold to me) but they are not "photorealistic".

Best regards,
Vlado
(hiding for cover)
Go to hell Vlado!  Just kidding, what are you going to regret, we all have great respect for you and take your advice seriously.
Title: Re: Tonemapping - Plz Halp
Post by: lupaz on 2020-05-07, 17:34:00
The fastest and closest I see as human eye style of images is when you bring a dng file into photoshop and do the auto camera raw filter.
Title: Re: Tonemapping - Plz Halp
Post by: dfcorona on 2020-05-07, 17:36:58
I think the trick really of making a render more of what the human eye can see is in the tonemapping/color management.  Cameras blow out highlights and darken shadowed areas, combating those two things I think will get you a lot closer.  I for one always thought (wondered) if each person sees the same anyway even in colors perceived.
Title: Re: Tonemapping - Plz Halp
Post by: lupaz on 2020-05-07, 17:40:59
No, it's not "photoreal". There is no real-world photographic camera that can produce those results. They are very nice images for sure and it's fine if people prefer them (even though they always feel a little off and too cold to me) but they are not "photorealistic".

They feel coldish to me too to be honest, and slightly 3d-ish on large flat surfaces.
But there's something about the focus on some Fstorm rendering that makes me feel calm. Is that weird? :/
Title: Re: Tonemapping - Plz Halp
Post by: Designerman77 on 2020-05-07, 17:48:23
And sorry to say... but from FStorm I see images from at user levels - and it is immediately visible that the engine has a more photoreal way to calculate light, contrasts and colors.
I'm sure I will regret jumping into this thread, but I feel I have to say this. No, it's not "photoreal". There is no real-world photographic camera that can produce those results. They are very nice images for sure and it's fine if people prefer them (even though they always feel a little off and too cold to me) but they are not "photorealistic".

Best regards,
Vlado
(hiding for cover)


I agree with you Vlado. FStorm renders (in average) are also not the super duper 100% realistic render. But this fact does not jump into your eye at first sight. You have to look twice. :)
And yes, the light atmosphere in most FStorm pics is indeed a bit greenish & cold. To my eye, exactly this makes them look camera-like.
During this thread I started pushing the curves in the VFB in this direction... and somehow it looks good / cam-like to me, since one has lees magenta/red tint and the whites start to look more neutral.



Title: Re: Tonemapping - Plz Halp
Post by: James Vella on 2020-05-07, 17:50:35
I think the trick really of making a render more of what the human eye can see is in the tonemapping/color management.  Cameras blow out highlights and darken shadowed areas, combating those two things I think will get you a lot closer...

This is basically what I mean by the way the human eye perceives things, thats a good way to put it.

No, it's not "photoreal". There is no real-world photographic camera that can produce those results...

Are you referring to the render engine or the process of capturing light, color and contrast with a camera?
Title: Re: Tonemapping - Plz Halp
Post by: Designerman77 on 2020-05-07, 17:55:53
No, it's not "photoreal". There is no real-world photographic camera that can produce those results. They are very nice images for sure and it's fine if people prefer them (even though they always feel a little off and too cold to me) but they are not "photorealistic".

They feel coldish to me too to be honest, and slightly 3d-ish on large flat surfaces.
But there's something about the focus on some Fstorm rendering that makes me feel calm. Is that weird? :/




No, its not weird. That color tint has the same effect on me. :))))
Yesterday I thought exactly about this specific point in context of renders: colors and their effect on perception psychology.

From my own renders I drew the conclusion that those feel most fake to my eye, which have a magenta/red tint or are too yellowish. Blueish/greenish tint, especially on the whites, brown tones and blacks somehow look more photo-like to me.
Title: Re: Tonemapping - Plz Halp
Post by: dfcorona on 2020-05-07, 18:04:09
I did an animation with Fstorm recently, and had to offset the hue to get the cold green tint out of the renders funny enough.
Title: Re: Tonemapping - Plz Halp
Post by: Designerman77 on 2020-05-07, 19:16:09
I did an animation with Fstorm recently, and had to offset the hue to get the cold green tint out of the renders funny enough.

Interesting to hear. But I can perfectly imagine that. Saw in tutorials from Johannes Linqvist that in his basic setting, renders look quite greenish in the blacks.

While rendering on a large job with tens and tens of white, empty rooms, I had plenty of opportunity to observe what curves do with those basic colors.
Reducing the red tone in the lows / shadows indeed give that look which the eye percepts as more natural / photographic.
And this is also logical, because usually shadows are more blueish / cold tinted.
And in Standard render settings of Corona, this is not really the case. You have to play with the red curve.

Maybe, just maybe this automatic desaturation of red/magenta in the shadows could be made standard render setting? In Kim Amlamnd LUT 01 this is standard... but very extrem.
Hmmm... just a thought.




Title: Re: Tonemapping - Plz Halp
Post by: twoheads on 2020-05-07, 19:36:15
...
Title: Re: Tonemapping - Plz Halp
Post by: cjwidd on 2020-05-08, 12:23:48
Well, because of you all, I installed FStorm to see what the fuss was about. One of the first things I noticed was that Dubcat's Fstorm LUTs are very strong imitations of the default tonemapping in Fstorm.

My first impression is that FStorm is like driving a rally car or a Koenigsegg, while Corona is like a Porsche or Ferrari. There is a difference in the manner of safety nets in place to guide the experience and at the end of the day they are just different things - reminds me a lot of Unity vs. Unreal.

I spent the last couple nights comparing basic scenes - thinking I'd scale up to something more complex - but the more I tried to control for different variables in the renderers, the more futile it felt to do so. The two renderers just aren't the same: shader, render settings, tonemapping, enviro mapping, gamma controls, etc. I had some naive sense that updating a scene to run in Fstorm from Corona would be a little more than trivial, but that was not my experience.

Nevertheless I did some basic tests in which I attempted to control for as many extraneous variables as possible (given my limited understanding of Fstorm) and was surprised by the results.
(https://i.imgur.com/VzFiL5E.png) (https://i.imgur.com/JJajU18.png)(https://i.imgur.com/yPAIyI3.png)

(https://i.imgur.com/OPLepr5.png)(https://i.imgur.com/RdxF1qA.png)(https://i.imgur.com/RNw5nOq.png)
Title: Re: Tonemapping - Plz Halp
Post by: bluebox on 2020-05-08, 14:45:09
Hard to draw a definitive conclusion taking into account that you are not a proficient Fstorm user and this may depend on the shader setup but Corona result clearly different from Fstorm.

Super easy to observe the differences while you overlay the renders. In the floor shader example there is waaay more detail in the shadows and highlights are better preserved in the Fstorm example.

There seems to be some exposure difference but even while bringing the two examples to aproximately the same level shadows in Fstorm have nice definition while the one in Corona example have some sort of patina-crush overlay on them.
Title: Re: Tonemapping - Plz Halp
Post by: Designerman77 on 2020-05-08, 15:06:06
...


Hahaaaaa... LOOOOOL !!!!!
You made my day. :)
Title: Re: Tonemapping - Plz Halp
Post by: lupaz on 2020-05-08, 15:53:41
Nevertheless I did some basic tests in which I attempted to control for as many extraneous variables as possible (given my limited understanding of Fstorm) and was surprised by the results.

I can barely see any difference.
Fstorm and corona next to each other. Image divided in half. I see a little more blur in the fstorm rendering.

(https://i.imgur.com/EGGXKIz.jpg)
Title: Re: Tonemapping - Plz Halp
Post by: hldemi on 2020-05-08, 15:56:30
This is really hard to do. Fstorm vs Corona comparison that is.

Only right test would be to give same guy thats equally good with Fstorm and Corona to 3d recreate same reference photo with both engines. Then to compare those and to see how many steps it took for both to get on that level.
Personally I only care if both could do the same job equally well, I dont mind working a bit harder with one or the other to get there.


Title: Re: Tonemapping - Plz Halp
Post by: PROH on 2020-05-08, 16:06:44
@cjwidd - where did you find those Dubcats fstorm LUTs? Can you post a link, or share them? Would realy like to try them out myself :)
Title: Re: Tonemapping - Plz Halp
Post by: dfcorona on 2020-05-08, 16:57:27
It's funny how we nitpick of such minute details of this vs that.  I say that in a good way cause that's what makes us better and software better.  That's why I always love comparison threads. In the end the client can't see the difference at all, getting past our own anal critiquing of our own work is much harder.
Title: Re: Tonemapping - Plz Halp
Post by: Designerman77 on 2020-05-08, 17:23:37
It's funny how we nitpick of such minute details of this vs that.  I say that in a good way cause that's what makes us better and software better.  That's why I always love comparison threads. In the end the client can't see the difference at all, getting past our own anal critiquing of our own work is much harder.

Even if clients do not see the difference on a conscientious level - but subconsciously he can be massively influenced by better lighting & tone mapping.
Yes, totally agree with you, by regularly questioning the status quo things and us get better.
Title: Re: Tonemapping - Plz Halp
Post by: Jpjapers on 2020-05-08, 17:25:55
@cjwidd - where did you find those Dubcats fstorm LUTs? Can you post a link, or share them? Would realy like to try them out myself :)

Here you go, Hopefully dubcat doesnt mind me resharing them.
Title: Re: Tonemapping - Plz Halp
Post by: Designerman77 on 2020-05-08, 17:26:35
What I actually wanted to post since months: look at natural light behavior in the photo taken in my living room. Just like a glass prism, even trivial objects do break light in its spectral colors.

I was wondering many times how rendered images would look if Corona calculated this effect...
Title: Re: Tonemapping - Plz Halp
Post by: Jpjapers on 2020-05-08, 17:34:02
What I actually wanted to post since months: look at natura light behavior in the photo taken in my living room. Just like a glass prism, even trivial objects do break light in its spectral colors.

I was wondering many times how rendered images would look if Corona calculated this effect...

I would think that is just an effect where the direct light has a blue cast, the umbra is just natural shadow and the colour in the penumbra is coming from the wood. If you set this up in corona exactly. I think the result would look the same or thereabouts.
Title: Re: Tonemapping - Plz Halp
Post by: Designerman77 on 2020-05-08, 17:45:49
What I actually wanted to post since months: look at natura light behavior in the photo taken in my living room. Just like a glass prism, even trivial objects do break light in its spectral colors.

I was wondering many times how rendered images would look if Corona calculated this effect...

I would think that is just an effect where the direct light has a blue cast, the umbra is just natural shadow and the colour in the penumbra is coming from the wood. If you set this up in corona exactly. I think the result would look the same or thereabouts.


Gonna test it by recreating a similar scene. But I observe this spectral effect on white walls caused by any edge that deflects the light, no matter what color the material has... can be a white window frame, etc.
So I assume it is in fact the spectral effect you most strongly see with prisms.
Title: Re: Tonemapping - Plz Halp
Post by: aldola on 2020-05-08, 17:47:54
I dont know if it make a lot of difference, but using fstorm i find the gamma input on the tone mapping very useful, i find that corona crush the shadows easily than fstorm, here is an example atached i usually lift the gamma a bit to compensate the lighting, i dont find a similar parameter in corona, may be curves but this is easier for me.



Title: Re: Tonemapping - Plz Halp
Post by: Jpjapers on 2020-05-08, 17:50:05

Gonna test it by recreating a similar scene. But I observe this spectral effect on white walls caused by any edge that deflects the light, no matter what color the material has... can be a white window frame, etc.
So I assume it is in fact the spectral effect you most strongly see with prisms.

The shadows appear coloured because the bright yellow light from the sun is blocked from the shadow area, leaving only indirect light and blue light and vice versa.
Title: Re: Tonemapping - Plz Halp
Post by: Designerman77 on 2020-05-08, 17:54:17

Gonna test it by recreating a similar scene. But I observe this spectral effect on white walls caused by any edge that deflects the light, no matter what color the material has... can be a white window frame, etc.
So I assume it is in fact the spectral effect you most strongly see with prisms.

The shadows appear coloured because the bright yellow light from the sun is blocked from the shadow area, leaving only indirect light and blue light and vice versa.

Well, maybe that's the reason, However, this effect is very strong in reality and I never see it in my renders. Only due to compression artifacts in JPGs. :)))))))

But: you clearly see that the shadows are actually multiple shadows overlapping, with the spectral colors at the edges.
I remember we learned about this effect in physics in the 9th grade. :)
Title: Re: Tonemapping - Plz Halp
Post by: Jpjapers on 2020-05-08, 18:00:46
But: you clearly see that the shadows are actually multiple shadows overlapping, with the spectral colors at the edges.
I remember we learned about this effect in physics in the 9th grade. :)

Yeah because the colours are only in the areas where the indirect and direct lighting bounces dont cancel each other out.
Title: Re: Tonemapping - Plz Halp
Post by: PROH on 2020-05-08, 19:53:49
@ Jpjapers - Thanks :)
Title: Re: Tonemapping - Plz Halp
Post by: cjwidd on 2020-05-08, 21:34:37
Hard to draw a definitive conclusion taking into account that you are not a proficient Fstorm user and this may depend on the shader setup [...]

I'm sort of on the fence about whether this is important for this comparison; if the intention were to induce Corona to emulate Fstorm in its entirety, than this experiment is not useful. The point here was to compare a simple stimulus in both renderers as close as possible to default. Of course if we leave Corona at literal default, the comparison is not meaningful at all because Corona does not tonemap by default, i.e. straw man comparison.

Regardless, I'm sure there is more that could be done to the shader in Corona to get better visual parity with Fstorm.

That being said, there is something unusual happening in the grey box scenes (third image in each set) because the grey floor / walls are MUCH brighter in the Corona scene by comparison - same 186,186,186 grey material that appears in the first render of each group.
Title: Re: Tonemapping - Plz Halp
Post by: cjwidd on 2020-05-08, 21:52:24
I can barely see any difference.
Fstorm and corona next to each other. Image divided in half. I see a little more blur in the fstorm rendering.

I guess I'm being trolled aren't you the one that allegedly removed Fstorm watermarks from some earlier tests?

Just to be clear, comparing the second shot for both Fstorm and Corona Renderer does not produce an identical result on my end.

The grey cylinder was used to calibrate the Exposure (to some extent). I found that -.75 EV brought the Corona Renderer version in-line with the Fstorm render. The parquet material was applied to the cylinder and rendered unadjusted from the grey cylinder scene.

(https://i.imgur.com/005EVcZ.png)
Title: Re: Tonemapping - Plz Halp
Post by: James Vella on 2020-05-08, 22:10:58
I guess I'm being trolled - aren't you the one that allegedly removed Fstorm watermarks from some earlier tests?

lol!! I think you are being trolled :D Made me giggle though
Title: Re: Tonemapping - Plz Halp
Post by: cjwidd on 2020-05-08, 22:13:01
Wow, fake news even on the Corona forums - great...

@lolec If you are editing watermarks out in PS and reposting here, then I would invite you to stop posting to the thread. I'm not sure why that type of behavior would be considered warranted or appropriate for the present discussion. If you can't be honest or transparent in your dealings on the forum, then please consider sharing your thoughts elsewhere.
Title: Re: Tonemapping - Plz Halp
Post by: Designerman77 on 2020-05-08, 22:17:56
Wow, fake news even on the Corona forums - great...

@lolec If you are editing watermarks out in PS and reposting here, then I would invite you to stop posting to the thread. I'm not sure why that type of behavior would be considered warranted or appropriate for the present discussion. If you can't be honest or transparent in your dealings on the forum, then please consider sharing your thoughts elsewhere.

I came here to learn about how we can get more realistic renders. Dudes, don't quarrel please.
Title: Re: Tonemapping - Plz Halp
Post by: lolec on 2020-05-08, 23:13:16
Wow, fake news even on the Corona forums - great...

@lolec If you are editing watermarks out in PS and reposting here, then I would invite you to stop posting to the thread. I'm not sure why that type of behavior would be considered warranted or appropriate for the present discussion. If you can't be honest or transparent in your dealings on the forum, then please consider sharing your thoughts elsewhere.

1. Unless I broke a forum rule inherited from 19-century prudes, I will respectfully decline your invitation and continue to post.

2. There are many theories floating around, mine was that people had a slight bias to quickly call Fstorm renders better. I TESTED that theory and at least two people (Who, btw took it waaaaay better than you) partially confirmed that sometimes that can happen. NO this does not mean there is no difference between Fstorm and Corona, but maybe we are now open to the possibility of human bias, maybe just a tiny percent. I think that is a way of moving the conversation forward and is moving us all towards a more objective analysis.

3. Please stop using the words Honest and Transparent referring to this. It was a silly experiment done tongue in cheek, absolutely NO ONE was hurt, other than your butt, apparently.

4. I DO see a difference in the images you posted... they are clearly different. I'm not sure why LUPAZ posted an image that looks modified to reduce the difference, maybe he is in fact trolling you, and maybe that made you angry. But you see... LUPAZ is not the same as LOLEC. For someone who claims to see minute differences, you missed a big one there. Here is an image that might help.

(https://i.imgur.com/lmN5kxQ.jpg)
I don't need to tell you which one I think is better :)

Again, I don't think faking the watermark hurt anyone and we are all adults who can laugh about that kind of stuff, we want the same thing, don't fight. I hope to keep this conversation going as I'm learning from this trhead and I hope others are too.
Title: Re: Tonemapping - Plz Halp
Post by: cjwidd on 2020-05-08, 23:46:24
@lolec thanks for clarifying, the post has been edited for accuracy
Title: Re: Tonemapping - Plz Halp
Post by: lolec on 2020-05-09, 02:46:46
What I actually wanted to post since months: look at natural light behavior in the photo taken in my living room. Just like a glass prism, even trivial objects do break light in its spectral colors.

I was wondering many times how rendered images would look if Corona calculated this effect...

That is a great example of how you can provide more realism with any engine! And how attention to detail plays a big role some times.

Even though it might look like a prism or dispersion, it is actually a much simpler phenomenon. This video might be interesting to you:

So, what is happening is that the light SOURCE has all sort of colors, intensities and directions. I would need to see the outside of that window to understand what's happening, but because of the orange colors in the light, my guess is blue sky and there is a brick wall nearby? Maybe.

Anyway, HDRs do an OK job at emulating exterior lighting, but to get the full effect you need to add nearby object that can interact with the light in a natural way.

Here is an image I made using many suns with different colors and intensities. Of course this is not natural! but I was trying to match your picture and show how that effect is the result of light source and not light dispersion.

(https://i.imgur.com/A0aVTYT.jpg)

Title: Re: Tonemapping - Plz Halp
Post by: lupaz on 2020-05-09, 16:27:34

Just to be clear, comparing the second shot for both Fstorm and Corona Renderer does not produce an identical result on my end.


(https://i.imgur.com/005EVcZ.png)

I just adjusted the exposure in photoshop.
Title: Re: Tonemapping - Plz Halp
Post by: lupaz on 2020-05-09, 18:03:20
One more test I wanted to make.
This test isn't directly related to tone mapping, but I think that tone mapping is affected by it.


For this test I'm using path tracing for secondary bounces. The images have no saturation. I did try to match contrast and exposure slightly (without going crazy about it). No bloom, no DOF.
I notice a couple of things that I think are helping Fstorm almost unwantedly:

1- The energy of bounced light is much less in Fstorm. It makes it look more 3D-like, but it separates colors from surface to surface and adds deeper clarity to corners and small cracks or spaces.

I really wish there was a setting in corona to lower this energy that worked better than Max Sample Intensity. A while ago I started this thread about this issue: https://forum.corona-renderer.com/index.php?topic=23129.msg164407#msg164407 (https://forum.corona-renderer.com/index.php?topic=23129.msg164407#msg164407)

I also think this is the reason why nobody in this thread is talking about exterior renderings: because secondary bounces don't play such an important role in exteriors. If the issue with corona was exclusively tone mapping, why nobody is talking about exterior renderings?
Note: I don't think this is necessarily an issue. Corona looks great, but it seems that the trend in photos and renderings is this one: one where every surface is very separate from each other clearly.


(https://i.imgur.com/s1zaSxY.jpg)
(https://i.imgur.com/BKXi5ij.jpg)

2- Corona applies blur to all textures by default. Fstorm doesn't even have blur in their material AFAIK.
Why? Why blur by default?
The only reason I don't remove it is because Corona's bump mapping doesn't work without blur.

(https://i.imgur.com/9NGxxIi.jpg)


3- And one more thing. This is a question:
Does anyone know what this does exactly?

(https://i.imgur.com/pGlDHIF.jpg)
Title: Re: Tonemapping - Plz Halp
Post by: Designerman77 on 2020-05-09, 18:07:01
What I actually wanted to post since months: look at natural light behavior in the photo taken in my living room. Just like a glass prism, even trivial objects do break light in its spectral colors.

I was wondering many times how rendered images would look if Corona calculated this effect...

That is a great example of how you can provide more realism with any engine! And how attention to detail plays a big role some times.

Even though it might look like a prism or dispersion, it is actually a much simpler phenomenon. This video might be interesting to you:

So, what is happening is that the light SOURCE has all sort of colors, intensities and directions. I would need to see the outside of that window to understand what's happening, but because of the orange colors in the light, my guess is blue sky and there is a brick wall nearby? Maybe.

Anyway, HDRs do an OK job at emulating exterior lighting, but to get the full effect you need to add nearby object that can interact with the light in a natural way.

Here is an image I made using many suns with different colors and intensities. Of course this is not natural! but I was trying to match your picture and show how that effect is the result of light source and not light dispersion.

(https://i.imgur.com/A0aVTYT.jpg)



Quite cool how you recreated the effect. Does it not bring a nice level of realism, compared to boring grey shadows?

Your guess is correct, outside is a building with a wooden outer shell that reflects a lot of warm / orange light when it is indirectly lit by the sun.
However... from HDRs, which quite often have large areas with different colors, I do not consciously remember to have seen that effect.
I´ll keep an eye on it. :)

Title: Re: Tonemapping - Plz Halp
Post by: Designerman77 on 2020-05-09, 18:10:43
One more test I wanted to make.
This test isn't directly related to tone mapping, but I think that tone mapping is affected by it.


For this test I'm using path tracing for secondary bounces. The images have no saturation. I did try to match contrast and exposure slightly (without going crazy about it). No bloom, no DOF.
I notice a couple of things that I think are helping Fstorm almost unwantedly:

1- The energy of bounced light is much less in Fstorm. It makes it look more 3D-like, but it separates colors from surface to surface and adds deeper clarity to corners and small cracks or spaces.

I really wish there was a setting in corona to lower this energy that worked better than Max Sample Intensity. A while ago I started this thread about this issue: https://forum.corona-renderer.com/index.php?topic=23129.msg164407#msg164407 (https://forum.corona-renderer.com/index.php?topic=23129.msg164407#msg164407)

I also think this is the reason why nobody in this thread is talking about exterior renderings: because secondary bounces don't play such an important role in exteriors. If the issue with corona was exclusively tone mapping, why nobody is talking about exterior renderings?
Note: I don't think this is necessarily an issue. Corona looks great, but it seems that the trend in photos and renderings is this one: one where every surface is very separate from each other clearly.


(https://i.imgur.com/s1zaSxY.jpg)
(https://i.imgur.com/BKXi5ij.jpg)

2- Corona applies blur to all textures by default. Fstorm doesn't even have blur in their material AFAIK.
Why? Why blur by default?
The only reason I don't remove it is because Corona's bump mapping doesn't work without blur.

(https://i.imgur.com/9NGxxIi.jpg)


3- And one more thing. This is a question:
Does anyone know what this does exactly?

(https://i.imgur.com/pGlDHIF.jpg)


Nice observation!
Title: Re: Tonemapping - Plz Halp
Post by: romullus on 2020-05-09, 18:35:32
Your guess is correct, outside is a building with a wooden outer shell that reflects a lot of warm / orange light when it is indirectly lit by the sun.
However... from HDRs, which quite often have large areas with different colors, I do not consciously remember to have seen that effect.
I´ll keep an eye on it. :)

HDRI can't replace actually modeled 3D enviroment. It's simply impossible. HDRI is just mere approximation of complex light rays interaction with enviroment and some natural phenomena are impossible, or very hard to bake into 2 dimensional HDRI. If you want ultimate realism, you have to build full enviroment :]
Title: Re: Tonemapping - Plz Halp
Post by: Designerman77 on 2020-05-09, 18:55:50
HDRI can't replace actually modeled 3D enviroment. It's simply impossible. HDRI is just mere approximation of complex light rays interaction with enviroment and some natural phenomena are impossible, or very hard to bake into 2 dimensional HDRI. If you want ultimate realism, you have to build full enviroment :]
[/quote]


Yep... looks like this. Thanks for specifically confirming it.
I guess then we have to place some orange & blue blocks in front of the windows sometimes... with "invisible to cam & reflections"-tag, so we get colored shadows. :)))
Title: Re: Tonemapping - Plz Halp
Post by: agentdark45 on 2020-05-09, 19:10:49
3- And one more thing. This is a question:
Does anyone know what this does exactly?

(https://i.imgur.com/pGlDHIF.jpg)

Great test btw, the seperate surface effect is very noticable on the Fstorm renders especially in the corners.

The relative tickbox essentially changes the "max sample intensity" (as a comparison to Corona) per camera view/frame by detecting how bright light sources are. Its quite hit and miss so I usually untick it and keep the power to around 3-6 for frame lighting consistency.
Title: Re: Tonemapping - Plz Halp
Post by: cjwidd on 2020-05-09, 22:58:11
@lopaz Right, I see that now - I confused your post with another user. Sorry if you mentioned the exposure adjustment before, I might have missed it.
Title: Re: Tonemapping - Plz Halp
Post by: Designerman77 on 2020-05-10, 16:54:13
So, dudes & devs:

thanks to a hint from our buddy CJWIDD, I switched to Dubcat´s ACES simulation HC 0.7, etc.
After tens of renders (interiors) in the last days, this will stay standard setting for me... despite the stronger burning in the highlights.

Renders (contrasts, gradients, etc.) look waaaay more photo-like and more natural to the eye with HC 0.7. Especially in small rooms with poor light sources, you get much more energy.
Details that looked totally washed out at HC 1 and above, suddenly appear and the lighting becomes natural and alive.

In my humble opinion, the base setting of the HC in Corona seems too high. That's why images always look rather washed out & grayish and one messes around with contrasts to compensate it - with the known side effects of color burning, etc.

HC lower than 1 as a standard and a better / stronger effect of filmic highlights, so one can reduce clipping to a natural degree when needed, would be perfect in Corona.

What do you guys think?
Title: Re: Tonemapping - Plz Halp
Post by: Jpjapers on 2020-05-10, 22:57:00
So, dudes & devs:

thanks to a hint from our buddy CJWIDD, I switched to Dubcat´s ACES simulation HC 0.7, etc.
After tens of renders (interiors) in the last days, this will stay standard setting for me... despite the stronger burning in the highlights.

Renders (contrasts, gradients, etc.) look waaaay more photo-like and more natural to the eye with HC 0.7. Especially in small rooms with poor light sources, you get much more energy.
Details that looked totally washed out at HC 1 and above, suddenly appear and the lighting becomes natural and alive.

In my humble opinion, the base setting of the HC in Corona seems too high. That's why images always look rather washed out & grayish and one messes around with contrasts to compensate it - with the known side effects of color burning, etc.

HC lower than 1 as a standard and a better / stronger effect of filmic highlights, so one can reduce clipping to a natural degree when needed, would be perfect in Corona.

What do you guys think?

0.7 has been my starting point for a long time though i sometimes take it up to Max 2.5 in some circumstances.
Title: Re: Tonemapping - Plz Halp
Post by: lupaz on 2020-05-10, 23:18:16
So, dudes & devs:

thanks to a hint from our buddy CJWIDD, I switched to Dubcat´s ACES simulation HC 0.7, etc.


Could you give all the settings and files (cube file?), if any? I'd like to make some tests and it'sa looong thread. Thanks.
Title: Re: Tonemapping - Plz Halp
Post by: Designerman77 on 2020-05-10, 23:37:24
So, dudes & devs:

thanks to a hint from our buddy CJWIDD, I switched to Dubcat´s ACES simulation HC 0.7, etc.


Could you give all the settings and files (cube file?), if any? I'd like to make some tests and it'sa looong thread. Thanks.


Hey, thanks!

I´m in C4D, I guess you work in Max.
Here is a screenshot of my settings I use for rendering tens of these types of white rooms.
Not a project of high artistic value... The client needs them quick and quicker. :)))))

However, with HC 0.7 etc. one sees a huge difference.
HC 1.0 + looks way more dull, grayish, contrasts & transitions on walls are very clamped, less contact shadows in the edges & corners, etc.
Title: Re: Tonemapping - Plz Halp
Post by: PROH on 2020-05-11, 02:44:48
@lupaz - See post #229 for Dubcats settings.
Title: Re: Tonemapping - Plz Halp
Post by: lupaz on 2020-05-11, 04:21:03
@lupaz - See post #229 for Dubcats settings.

got it.
thanks man
Title: Re: Tonemapping - Plz Halp
Post by: cjwidd on 2020-05-11, 07:32:52
@Designerman77 looks pretty nice! The scene is lit with HDRI only or sun/sky with backplate?
Title: Re: Tonemapping - Plz Halp
Post by: Designerman77 on 2020-05-11, 09:46:24
@Designerman77 looks pretty nice! The scene is lit with HDRI only or sun/sky with backplate?


Hey cjwidd... It is so funny how others see one´s renders... while I am mostly not satisfied with them.
Honestly, mostly because of that light / contrasts / colors - topic all of us discuss here. Especially in very white rooms with little contrasting furniture etc.
But thanks. :)

A simple HDR sky and a messy, low res backplate - because the client wants some green behind the window.
As mentioned... this specific job is not about perfection at all. Thanks God the rooms have to also be rendered with furniture. At least a bit of "art". :)


HDR is from "free HDR skies", number 129
I like that those guys make 360° HDRs, so you get natural lighting on your walls & ceiling from greenery in the HDR.
Title: Re: Tonemapping - Plz Halp
Post by: Designerman77 on 2020-05-11, 09:59:14
A sub-topic that - in my opinion - is very important in this context, is the highlight compression. This would deserve a special attention from the devs.

From electronic music recording, some of you might know compression and... really great compression like for example that from UAD.
"Normal" audio compressors brutally cut away frequencies, leaving behind a dull and deaf sound without details.
A similar effect I see in digital picture compression.

Question: is it technically possible to program a HC that compresses while still leaving much details?
Or the same behavior for the Filmic Highlight - especially handy when using HC lower than 1.

At the moment, either you crank up the HC and land in a dull image, or you lower HC, get way nicer lighting but the Filmic Highlight has to be pushed up to brutal values as compensation,
so your highlight lose most details.
Title: Re: Tonemapping - Plz Halp
Post by: lupaz on 2020-05-11, 16:47:40
I've been using <1.0 HC, as is described in Dubcat's ACES emulation settings, and it *feels* like it brings back dynamic range, i.e. the image looks more punchy, more depth

I never tried those settings. I have to admit they sound completely nonsense for me, on paper at least. Maybe the combination with filmic highlight counterbalances the 0.7 HC compression. I'll give it a go tho, as Dubcat always conducted is tests rigorously and always delivered good stuff. Settings are attached for those wondering.

This is without any LUT?
Title: Re: Tonemapping - Plz Halp
Post by: maru on 2020-05-11, 17:11:24
Great to see that fstorm still does heavy GI clamping. It was the same last time we checked. ;)
I wonder how fast it would be with GI clamping on Corona level.
Title: Re: Tonemapping - Plz Halp
Post by: lupaz on 2020-05-11, 20:06:54
So, dudes & devs:

thanks to a hint from our buddy CJWIDD, I switched to Dubcat´s ACES simulation HC 0.7, etc.
After tens of renders (interiors) in the last days, this will stay standard setting for me... despite the stronger burning in the highlights.

Renders (contrasts, gradients, etc.) look waaaay more photo-like and more natural to the eye with HC 0.7. Especially in small rooms with poor light sources, you get much more energy.
Details that looked totally washed out at HC 1 and above, suddenly appear and the lighting becomes natural and alive.

In my humble opinion, the base setting of the HC in Corona seems too high. That's why images always look rather washed out & grayish and one messes around with contrasts to compensate it - with the known side effects of color burning, etc.

HC lower than 1 as a standard and a better / stronger effect of filmic highlights, so one can reduce clipping to a natural degree when needed, would be perfect in Corona.

What do you guys think?

In my opinion you loose contrast with this setup.
But at this point it's a matter of preference or taste I think. Same as with LUTs.
Title: Re: Tonemapping - Plz Halp
Post by: hldemi on 2020-05-11, 20:47:03
A sub-topic that - in my opinion - is very important in this context, is the highlight compression. This would deserve a special attention from the devs.

From electronic music recording, some of you might know compression and... really great compression like for example that from UAD.
"Normal" audio compressors brutally cut away frequencies, leaving behind a dull and deaf sound without details.
A similar effect I see in digital picture compression.

Question: is it technically possible to program a HC that compresses while still leaving much details?
Or the same behavior for the Filmic Highlight - especially handy when using HC lower than 1.

At the moment, either you crank up the HC and land in a dull image, or you lower HC, get way nicer lighting but the Filmic Highlight has to be pushed up to brutal values as compensation,
so your highlight lose most details.

I figured that filmic highlights on 1 reduces all of the light dynamics but real magic happens at values infinitely close to 1 haha. around 0.95-0.99 is sweet spot.
Title: Re: Tonemapping - Plz Halp
Post by: Designerman77 on 2020-05-11, 22:07:18
0.7 has been my starting point for a long time though i sometimes take it up to Max 2.5 in some circumstances.
[/quote]


Since I realized how dull and grey images get, as soon as you touch the HC... even a bit over 1.0, I keep my fingers away from it and only use filmic highlight, wich only affects
the very bright area. I observed that cranking up filmic highlights even increases light dynamic in other areas, such as on white walls.

From my early days with rendering, when I worked with Max (meanwhile with C4D), I remember that the on-board highlight compression in Max / MentalRay only affected the burnt lights,
without diminishing the overall dynamics. That was 2009 ! and you could get some pretty nice images.

That's what I would actually also expect from the Corona HC. Compress the clipping but don't dip the rest of the image into grey light.
Title: Re: Tonemapping - Plz Halp
Post by: Designerman77 on 2020-05-11, 22:09:33

I figured that filmic highlights on 1 reduces all of the light dynamics but real magic happens at values infinitely close to 1 haha. around 0.95-0.99 is sweet spot.
[/quote]


Yes, I confirm your observation! :)

In extreme light situations, when lower filmic highlight values don't do the job, 8.5 - 9.9 can do miracles. :)))))
But if it eats up too many details in other areas, I leave it a bit burnt and clamp it in PS.
Title: Re: Tonemapping - Plz Halp
Post by: Designerman77 on 2020-05-11, 22:15:08

I've been using <1.0 HC, as is described in Dubcat's ACES emulation settings, and it *feels* like it brings back dynamic range, i.e. the image looks more punchy, more depth
[/quote]

I never tried those settings. I have to admit they sound completely nonsense for me, on paper at least. Maybe the combination with filmic highlight counterbalances the 0.7 HC compression. I'll give it a go tho, as Dubcat always conducted is tests rigorously and always delivered good stuff. Settings are attached for those wondering.
[/quote]

This is without any LUT?
[/quote]


No, with Kim Amland 02.
Sorry, I forgot to mention it.

Title: Re: Tonemapping - Plz Halp
Post by: hldemi on 2020-05-13, 16:28:28
Designman77, gave myself a go at empty apartment rendering. Also HC 0.7 but went with soft blacks in curves to get filmic feel.
I feel that contrast need to be lowered far under 1 if we go with very low HC values.
Title: Re: Tonemapping - Plz Halp
Post by: cjwidd on 2020-05-14, 04:20:29
@hldemi can you post a screenshot of the tonemapping settings for this shot, including any LUTs or curves that were used, and what was the light source(s)?
Title: Re: Tonemapping - Plz Halp
Post by: hldemi on 2020-05-14, 16:31:52
@hldemi can you post a screenshot of the tonemapping settings for this shot, including any LUTs or curves that were used, and what was the light source(s)?

Sure. Its in attachment, I just did 20 passes in this SS. Original render took around 5 minutes.

As a LUT I used barnet from DELUTS 4 collection. It just give a bit of contrast and warmth. As you can see curve is just to for black. Always a bit up, I hate crushing blacks.
Light is extremely simple, only 2 light sources, corona sun and corona sky. Corona 5 not C6 daily.
Title: Re: Tonemapping - Plz Halp
Post by: Designerman77 on 2020-05-14, 17:21:58
@hldemi can you post a screenshot of the tonemapping settings for this shot, including any LUTs or curves that were used, and what was the light source(s)?

Sure. Its in attachment, I just did 20 passes in this SS. Original render took around 5 minutes.

As a LUT I used barnet from DELUTS 4 collection. It just give a bit of contrast and warmth. As you can see curve is just to for black. Always a bit up, I hate crushing blacks.
Light is extremely simple, only 2 light sources, corona sun and corona sky. Corona 5 not C6 daily.



Funny, I had a look at this thread exactly for this topic, and now you posted an example of your own. Very cool!

Exactly, pushing the blacks up in the curve became also my standard lately. Plus reducing the reds in the shadows makes images more realistic.
Also less reds in the mids & highlights has a positive effect on realism.

As mentioned before, I feel that the renders that look most fake, are those with too much red tone in the overall lighting... which... :)))) seems to appear quite often in Corona´s basic light behavior.
Remember? Someone here said "FStorm" looks always so greenish, etc. Yep... that greenish tint is somehow easier accepted by our eyes.


P.S. I try to not touch filmic shadows because it washes out your dynamics (similar to HC 1+), gradients on walls, contrasts etc.
That extra light it gives is not worth it. I rather get it by a bit higher exposure.
Title: Re: Tonemapping - Plz Halp
Post by: hldemi on 2020-05-14, 17:32:01
Thats because red is not usually dominant color in nature. Blue is sky and seas. Green is well rest of earth for most time we as humans evolved. So normally our eyes perceive those colors as more natural. This however is just a rule to get to photo-realistic image easier.  Its does not mean that reddish images cannot be extremely photorealistic .

To me, it does not matter much. One should strive to improve himself, render engines are fine :D
Title: Re: Tonemapping - Plz Halp
Post by: Designerman77 on 2020-05-14, 17:55:37
Thats because red is not usually dominant color in nature. Blue is sky and seas. Green is well rest of earth for most time we as humans evolved. So normally our eyes perceive those colors as more natural. This however is just a rule to get to photo-realistic image easier.  Its does not mean that reddish images cannot be extremely photorealistic .

To me, it does not matter much. One should strive to improve himself, render engines are fine :D

Totally agree with you. A to of 3D realism is about creating lighting, colors & contrasts we are used to in real life.
However, as you mentioned, reddish light is instinctively perceived as more "artificial" and "unnatural"... probably because from those hours of daylight,
only a short period is dominated by red light.
Also, if you look at small rooms with weak, reddish lamps in reality... it is really unpleasant to the eyes... and it looks exactly like what it is: artificial... no matter if in a render or in reality. :)


Regarding "render engines are just fine" and it is up to us to create realistic images, I only agree 50%.
If the render engine simply does not simulate stuff, you can be Leonardo DaVinci and your images will never look real.

Just remember render engines 10 years ago... :))))


However, Corona is without doubt one of the best render engines on the market. I think among the top three.
And it is developing quite nicely.
Title: Re: Tonemapping - Plz Halp
Post by: hldemi on 2020-05-14, 18:40:52
Yeah but I am talking about industry standard physical ray tracers of modern day. All those engines are capable of creating images that would fool even most experienced eyes. If just for a second.

Regarding red lights. Yeah but orange is totally different story. Even at lowest point of sunset, light is still orange-ish. Also artificial can be equally photorealistic . Any light thats saturated more than lower 20% of the pallet looks artificial. This is why low contrast, desaturated images looks more natural. And again both can be photorealistic.
Title: Re: Tonemapping - Plz Halp
Post by: Designerman77 on 2020-05-14, 18:57:41
Yeah but I am talking about industry standard physical ray tracers of modern day. All those engines are capable of creating images that would fool even most experienced eyes. If just for a second.

Regarding red lights. Yeah but orange is totally different story. Even at lowest point of sunset, light is still orange-ish. Also artificial can be equally photorealistic . Any light thats saturated more than lower 20% of the pallet looks artificial. This is why low contrast, desaturated images looks more natural. And again both can be photorealistic.

Interesting, did not know about that 20% saturation "rule of thumb".
Of course, any light or color mood can look photo-realistic. Only that - as you also mentioned - certain color moods look more "real" or believable to most of us, in the sense that a photo taken on Mars looks less natural than one taken in Monument valley.

Title: Re: Tonemapping - Plz Halp
Post by: hldemi on 2020-05-14, 19:06:52
Thats totally true. However I think that we as viz artists should not focus on natural look per se. In my images I always strive for the mood. If I want to to get the mood of Tokyo bordel in 2254 I would go for the oversaturated artificial lighting. But in a context of arch viz, you are absolutely right, looks that mostly please clients  are well lit, natural, airy and welcoming looks. Thats why if you are viz artist, arch viz will be mostly limiting. This is partly the reason Alex Roman got away from archviz for a while.
Title: Re: Tonemapping - Plz Halp
Post by: cjwidd on 2020-05-21, 21:56:58
eh...

(https://i.imgur.com/QFOQBcg.png)
Title: Re: Tonemapping - Plz Halp
Post by: Designerman77 on 2020-05-22, 00:27:38
Also fron the F-Storm FB site...

The one who made this test allowed me to post his image her for comparison purposes.
Thanks for it, in case you read here, too. :)
Title: Re: Tonemapping - Plz Halp
Post by: lolec on 2020-05-22, 00:46:06
lol at the pathetic shading work on the corona version. That is not the render's fault, that user is either incompetent or intentionally misleading. look at the leather LOL
Title: Re: Tonemapping - Plz Halp
Post by: Designerman77 on 2020-05-22, 01:02:02
lol at the pathetic shading work on the corona version. That is not the render's fault, that user is either incompetent or intentionally misleading. look at the leather LOL

That dude stated that he was a Corona user and just tested FStorm...
That's at least what he said. Can be true, can be a lie... who knows?
Title: Re: Tonemapping - Plz Halp
Post by: lolec on 2020-05-22, 01:06:08
Maybe you should download Fstorm and give it a go for a few weeks. Report back.
Title: Re: Tonemapping - Plz Halp
Post by: Designerman77 on 2020-05-22, 01:21:02
Maybe you should download Fstorm and give it a go for a few weeks. Report back.

Impossible for me... on Mac machines & Radeon GPUs. :))))

However, my goal is for sure not to switch form Corona to FStorm.
I'm only interested in stuff that improves the image quality in the Corona renderer. And observing what others do is always useful.
Title: Re: Tonemapping - Plz Halp
Post by: Designerman77 on 2020-05-22, 01:29:13
Maybe you should download Fstorm and give it a go for a few weeks. Report back.


Ah, look, I found another image that this guy gave me.

Watch the totally pixelated map of the bricks in FStorm... I don't think he is a FStom-genius. :)))
Title: Re: Tonemapping - Plz Halp
Post by: lolec on 2020-05-22, 01:36:02
If you want to improve image quality you should switch to Windows, the vastly superior tool!!!

hehe, of course, I'm messing with you, the only thing worst than an extremely subjective corona vs fstorm comparision is a Windows to Mac comparison thread :) 

Corona render was founded with a revolutionary approach and user-centric philosophy.  Being used in production by many many users means new features are harder and harder to add, but I trust the team and the vision.

That's the same reason I don't like Fstorm. Single developer, self-aggrandizing "genius" aura, adds cool feature after cool feature but can't seem to be able to work with a team, can't seem to mind about mission-critical features for production.
He has an artist brain. Real-world, functional products need an equilibrium between artist brain and engineer brain.

Heres the cool thing, artist brain types are great at finding what people want and pushing the edges. Great mixed teams with great vision are great at making that available to the masses in a reliable way.

I  believe the GOOD things about Fstorm will eventually find it's way into corona, implemented in a robust and production-ready manner, instead of like a cool, tech demo.



Title: Re: Tonemapping - Plz Halp
Post by: lolec on 2020-05-22, 01:37:50
Maybe you should download Fstorm and give it a go for a few weeks. Report back.


Ah, look, I found another image that this guy gave me.

Watch the totally pixelated map of the bricks in FStorm... I don't think he is a FStom-genius. :)))

He doesn't know how to enable caustics in corona or what?

If you ask him for that scene, I can give it a go in Corona.
Title: Re: Tonemapping - Plz Halp
Post by: Designerman77 on 2020-05-22, 01:44:27
Maybe you should download Fstorm and give it a go for a few weeks. Report back.


Ah, look, I found another image that this guy gave me.

Watch the totally pixelated map of the bricks in FStorm... I don't think he is a FStom-genius. :)))

He doesn't know how to enable caustics in corona or what?

If you ask him for that scene, I can give it a go in Corona.


The bricks look more like a displacement problem in FS, don't you think?

I will try to find that thread on the FStorm FB page and ask him for the scene.
However, I already told him to get involved in this thread here, as he is an active Corona user... exactly for the reason that people will start asking me things. :))))


Title: Re: Tonemapping - Plz Halp
Post by: hldemi on 2020-05-22, 02:17:05
Lolec can you explain why are new features harder to implement if more users are using engine in production ?
I dont get the correlation. Would it not be the opposite, the bigger the user base, the more money, the bigger and more talented team, the more features. No ?
Title: Re: Tonemapping - Plz Halp
Post by: lolec on 2020-05-22, 02:44:59
Lolec can you explain why are new features harder to implement if more users are using engine in production ?
I dont get the correlation. Would it not be the opposite, the bigger the user base, the more money, the bigger and more talented team, the more features. No ?

Sure, I will try.

First, more money = larger team , unfortunately not always true. Finding talented people is incredibly hard. Even with all the money in the world. I bet the corona team hasn't gotten much bigger and most of the core developers have been there for years. VERY hard problem to solve, finding people.

When you have more users you have more "versions" of users.  THAUSANDS that use 3dsmax 2016, Thausands that NEED Phoenix for work. Or need to use their existing material libraries or absolutely NEED the render to be compatible with renderfarms.... the list goes on and on.

When you are creating a new niche product you can break compatibility or not work for 5% of people and that means a few dozen users, no big problem.

I will give you a good example:

Let's say corona team finds a way to make the render 50% faster but it will break compatibility with old materials. They CANT do it. There are a lot of people who depend on corona for work. They cant do something like that :(
Fstorm? he can probably still do stuff like that and upset people slightly, but not bring whole studios down.

Fstorm releases a feature, it doesn't work for some users, he gest 3 angry messages on facebook.

Corona CANT do it. they just cant afford to realease a broken feature. thousands of people depend on corona for work and need it to be rock solid.

It is a universal phenomenon, the larger the user base, the slower you can move. That's just the way it is :(

Title: Re: Tonemapping - Plz Halp
Post by: lolec on 2020-05-22, 03:39:42
Great real-world example:

Not only is Fstorm not supported by Rebus farm, but look at the list of supported plugins for corona just in rebusfarm!

https://mx.rebusfarm.net/en/3d-software/corona-render-farm

You can imagine there are probably a dozen ways of improving tonemapping, the corona developers are brilliant engineers, if we can find those in google I bet they can too. Well, if they want to do something, they have to consider compatibility with a huge number of dependencies, there are many users that expect corona to behave in a certain way, and "improving" things could mean they need to rebuild internal tools or rework scenes and assets. 

Vray started from scratch with NEXT, probably for a very similar reason. Backwards compatibility is a huge pain in the butt for new features, it is also a big part of why people choose to pay for corona, because they are investing much more than the license cost, they are investing hours and hours creating a workflow.

You can probably run windows 3.1 code on windows 10 today. That is the reason your bank uses Windows. While OSX can afford to loose 5% of it's user base by breaking compatibility in favor of fancy new features, windows cant afford to do that, hence, windows move slowly and OSX moved faster.
Title: Re: Tonemapping - Plz Halp
Post by: cjwidd on 2020-05-22, 07:52:37
I can't remember who said it first on this thread, but after converting scenes back in forth from Fstorm to Corona Renderer, and vice versa, I have to agree that the two renderers can produce very similar results. However, it seems that the default tonemapping settings in Fstorm are preferable to a lot of people.
Title: Re: Tonemapping - Plz Halp
Post by: Designerman77 on 2020-05-22, 10:22:23
Lolec can you explain why are new features harder to implement if more users are using engine in production ?
I dont get the correlation. Would it not be the opposite, the bigger the user base, the more money, the bigger and more talented team, the more features. No ?

Sure, I will try.

First, more money = larger team , unfortunately not always true. Finding talented people is incredibly hard. Even with all the money in the world. I bet the corona team hasn't gotten much bigger and most of the core developers have been there for years. VERY hard problem to solve, finding people.

When you have more users you have more "versions" of users.  THAUSANDS that use 3dsmax 2016, Thausands that NEED Phoenix for work. Or need to use their existing material libraries or absolutely NEED the render to be compatible with renderfarms.... the list goes on and on.

When you are creating a new niche product you can break compatibility or not work for 5% of people and that means a few dozen users, no big problem.

I will give you a good example:

Let's say corona team finds a way to make the render 50% faster but it will break compatibility with old materials. They CANT do it. There are a lot of people who depend on corona for work. They cant do something like that :(
Fstorm? he can probably still do stuff like that and upset people slightly, but not bring whole studios down.

Fstorm releases a feature, it doesn't work for some users, he gest 3 angry messages on facebook.

Corona CANT do it. they just cant afford to realease a broken feature. thousands of people depend on corona for work and need it to be rock solid.

It is a universal phenomenon, the larger the user base, the slower you can move. That's just the way it is :(



Well, Corona is not 100% "rock solid" either.
If it was the case, then why for heaven's sake does the "Quality Filter" in C4D still mess up all edges and surfaces, as soon as round-edge-map and / or bump map is applied?
This problem was literally shutting down my business for about two months when this denoising mode was integrated.
If the devs had not integrated the AI-denoiser after similar complaints from other users, I would have switched to Arnold as a last escape.

Lolec, for sure Corona is a fantastic engine, but we don't have to praise it like the golden calf. :)
Only constructive critique brings improvement...
Title: Re: Tonemapping - Plz Halp
Post by: Nejc Kilar on 2020-05-22, 10:49:34
@Designerman77

I don't want to be a negative Sally but I think the C4D version in general can't be compared to the 3ds Max version. At least not yet. We still have a lot of instabilities, full releases that break all the render farm compatibility / local render farm compatibility and imho it just isn't production ready yet (know of a few studios that agree too). I mean we can't output tonemapped images (8/16bit) without noticeable color space issues, let alone tackling things like bump maps not being able to scale... And the way releases are scheduled, you can't even use render farms reliably because they use the official version but those ship with really basic bugs more often than not and so you constantly need to switch between dailies and full releases.

As for this thread in general, to all of you who partake in the debate here, thank you for being cool! Reading through these pages is fun and while I agree a lot of it is subjective or could be tested better, I think it at the very least sparks another discourse on the topic. Thank you all!
Title: Re: Tonemapping - Plz Halp
Post by: Designerman77 on 2020-05-22, 11:48:54
@Designerman77

I don't want to be a negative Sally but I think the C4D version in general can't be compared to the 3ds Max version. At least not yet. We still have a lot of instabilities, full releases that break all the render farm compatibility / local render farm compatibility and imho it just isn't production ready yet (know of a few studios that agree too). I mean we can't even output tonemapped images (8/16bit) without noticeable color space issues, let alone things like bump maps not being able to scale... And the way releases are scheduled, you can't even use render farms reliably because they use the official version but those ship with really basic bugs more often than not and so you constantly need to switch between dailies and full releases.

As for this thread in general, to all of you who partake in the debate here, thank you for being cool! Reading through these pages is fun and while I agree a lot of it is subjective or could be tested better, I think it at the very least sparks another discourse on the topic. Thank you all!


Hmmm... makes me a bit sad to hear that the C4D version is significantly worse than the Max-version.
From the quality of the images in the net, I've always had this subjective impression... let aside the rumors that C4D users are "less experienced in average" or 3DsMax is soooo much better.



Title: Re: Tonemapping - Plz Halp
Post by: Nejc Kilar on 2020-05-22, 11:54:22
Well at this point its about reliability and usability and in my opinion the 3ds Max version is quite better off - especially on the reliability part. I'm sure we'll get there, eventually. GI, materials, tonemapping and things like that are obviously awesome in both versions :)

I suppose we shouldn't derail this thread with DCC specific stuff though. :P

To stay on topic, did we ever figure out what exactly was wrong with the current filmic implementation in the VFB? Afaik the shoulder slope was a bit off?
Title: Re: Tonemapping - Plz Halp
Post by: lolec on 2020-05-22, 12:09:25
Lolec can you explain why are new features harder to implement if more users are using engine in production ?
I dont get the correlation. Would it not be the opposite, the bigger the user base, the more money, the bigger and more talented team, the more features. No ?

Sure, I will try.

First, more money = larger team , unfortunately not always true. Finding talented people is incredibly hard. Even with all the money in the world. I bet the corona team hasn't gotten much bigger and most of the core developers have been there for years. VERY hard problem to solve, finding people.

When you have more users you have more "versions" of users.  THAUSANDS that use 3dsmax 2016, Thausands that NEED Phoenix for work. Or need to use their existing material libraries or absolutely NEED the render to be compatible with renderfarms.... the list goes on and on.

When you are creating a new niche product you can break compatibility or not work for 5% of people and that means a few dozen users, no big problem.

I will give you a good example:

Let's say corona team finds a way to make the render 50% faster but it will break compatibility with old materials. They CANT do it. There are a lot of people who depend on corona for work. They cant do something like that :(
Fstorm? he can probably still do stuff like that and upset people slightly, but not bring whole studios down.

Fstorm releases a feature, it doesn't work for some users, he gest 3 angry messages on facebook.

Corona CANT do it. they just cant afford to realease a broken feature. thousands of people depend on corona for work and need it to be rock solid.

It is a universal phenomenon, the larger the user base, the slower you can move. That's just the way it is :(



Well, Corona is not 100% "rock solid" either.
If it was the case, then why for heaven's sake does the "Quality Filter" in C4D still mess up all edges and surfaces, as soon as round-edge-map and / or bump map is applied?
This problem was literally shutting down my business for about two months when this denoising mode was integrated.
If the devs had not integrated the AI-denoiser after similar complaints from other users, I would have switched to Arnold as a last escape.

Lolec, for sure Corona is a fantastic engine, but we don't have to praise it like the golden calf. :)
Only constructive critique brings improvement...

I think that just proves my point. A new feature broke something for some users, and they had to spend significant amount of time fixing it until it was usable again.

Fstorm doesn’t have to worry about C4D ( they also have more devs, but the point is each dev has to worry about much more than just adding new features like a machinegun)

We are talking context here, I meant Corona is solid, robust, usable and compatible compared to Fstorm. As you all be comparing the two. There are more robust and production ready engines, those have an even harder time adding new features. Corona strikes some balance, a balance I like and prefer.

I think praise is part of criticism, I like that balance and would like them to continue prioritizing both aspects :)

Title: Re: Tonemapping - Plz Halp
Post by: Designerman77 on 2020-05-22, 20:03:23
Hey lolec, don't get me wrong, I DO love the Corona renderer!
Totally. And I could praise its 90% fantastic features 24/7. :)

However, let's get back to our light mapping / color grading topic this thread had started with.
After having rendered tens and tens of white empty interiors with parquet floor, this showed me quite clearly where the small but very significant things lay, which make renders often look somehow lame, dull and as if your eyes simply cannot focus on anything in the pics:

1. light-dark transitions on surfaces ( e.g. room walls ):

with "usual" HC-values ( 1+ ), those transitions get very washed out. ( To avoid that I arrived at 0.7 - 0.6 as may standard setting for HC. )
Same effect (dull image) , although by far not so strong, when Filmic Highlight is used.
Filmic highlight should behave a bit differently from how it does at the moment. Currently it softly clamps the highlights but also brightens the mids / darks. Result: transitions on walls / surfaces again get dull.
In my opinion, filmic highlight should do the soft clamping ONLY on the highlights... leaving the mids & darks unaffected. So you don't lose the subtle contrast which you never get back by brutally cranking up contrast values.

2. The correct proportion between lit surfaces and those in the shadow.
On this point I will not philosophy too much.

If one uses HC 0.7 - 0.6 this seems to be quite okay.
HC 0.7 - 0.6 seems to also be the answer to my first point (transitions)... and it could work fine if filmic highlights behaved like proposed in point Nr. 1.


Title: Re: Tonemapping - Plz Halp
Post by: lolec on 2020-05-22, 20:33:56
I think it’s fair to wish and hope for better features, but I will only complain about corona the day my renders look as good as the best corona renders I can find. Until then, I better work on myself.
Title: Re: Tonemapping - Plz Halp
Post by: Designerman77 on 2020-05-23, 00:18:55
I think it’s fair to wish and hope for better features, but I will only complain about corona the day my renders look as good as the best corona renders I can find. Until then, I better work on myself.

The best Corona-renders you can find online? One does not know how much post-work is in many of those renders.
As I stated before: a render engine should be so good that it makes post work just a matter of taste but not a necessity for a part of your renders. :)

However, I totally agree with your motto to work on oneself.
Title: Re: Tonemapping - Plz Halp
Post by: cjwidd on 2020-05-23, 01:46:24
with "usual" HC-values ( 1+ ), those transitions get very washed out. ( To avoid that I arrived at 0.7 - 0.6 as may standard setting for HC. )

I really have to agree with @Designerman77 on this issue. I've been conducted a huge variety of tonemapping tests over the last few months and I do not consistently arrive at visually satisfying result with HC = 1.0 without a LUT.
Title: Re: Tonemapping - Plz Halp
Post by: cjwidd on 2020-05-24, 08:43:57
Walls are diffuse (reflection level = 0) shades of grey - (186,186,186), (201,201,201), or (231,231,231) - meant to represent typical white wall paint values.
Scene is lit with v6 sun (FFFFFF) / sky (desat)

186,186,186
(https://i.imgur.com/veC5ZFo.png)

201,201,201
(https://i.imgur.com/MpUitX4.png)

231,231,231
(https://i.imgur.com/7mF9w41.png)

231,231,231 - EV: -1.025, default
*exposure matched to tonemapped versions
(https://i.imgur.com/haBy8Ha.png)

231,231,231 - EV: -1.025, default + Kim_Amland_fstorm 0.30 contrast
(https://i.imgur.com/zRWJWDZ.png)

scene setup
(https://i.imgur.com/GbohVkV.png)
Title: Re: Tonemapping - Plz Halp
Post by: cjwidd on 2020-08-13, 00:35:39
\canon-lut-201911\3dlut\65grid-3dlut\full-to-full-range\BT709_CanonLog2-to-BT709_WideDR_65_FF_Ver.2.0.cube

It doesnt give me the same result in Corona as Vray however.

edit (sorry I missed part of your question):
I chose it because there is only 3 to choose from as I need a log to rec709 df65 to match the setup of the corona scene. (6500kelvin).
- BT709_CanonLog2-to-BT709_WideDR_65_FF_Ver.2.0.cube
- BT709_CanonLog3-to-BT709_WideDR_65_FF_Ver.2.0.cube
- BT709_CanonLog-to-BT709_WideDR_65_FF_Ver.2.0.cube

The first one didnt have a vignette, so used that to keep things as clear as possible without adding additional parameters. Its how I work normally with the VFB, the more you play with the tone mapping controls (highlight burn, contrast etc) the more you complicate things when trying to compare results.

@James Vella, can you explain why we would use:
- Rec-709 LUT instead of a DCI-P3 LUT?
- 65 grid instead of 17 or 33 grid - is that just a resolution consideration?
- 1d vs. 3d LUT?
- log vs. log2 vs. log3?
Title: Re: Tonemapping - Plz Halp
Post by: James Vella on 2020-08-13, 19:22:37
@James Vella, can you explain why we would use:
- Rec-709 LUT instead of a DCI-P3 LUT?
- 65 grid instead of 17 or 33 grid - is that just a resolution consideration?
- 1d vs. 3d LUT?
- log vs. log2 vs. log3?

- I didnt see DCI-P3 in this list and I work in rec709 color space generally so that choice was easy for me, leaving 3 options to pick from.
- grid size yes basically resolution.
- 1D LUT is ok if you want to control contrast, white point, basic color adjustments otherwise if you need more precise data then 3D LUT is the best choice.
- log,log2,log3 are just different profiles. I chose the most neutral one for this example. You can take a look at a comparison video below for a better look at the curve (this is for s-log fyi).

if you check the manual that comes with the download you will see it goes into more detail regarding the file name/acronyms.

eg.
[Gamut]_[Gamma]-to-[Gamut]_[Gamma]_[GridNum]_[Range][Range]_[Verison].cube

BT709_CanonLog2-to-BT709_WideDR_65_FF_Ver.2.0.cube



Also a good short video on Wide DR

Title: Re: Tonemapping - Plz Halp
Post by: cjwidd on 2020-08-19, 07:45:48
Just discovered this write-up (https://www.jorgenhdri.com/explained/?fbclid=IwAR0C9L795PY4h_jWsB3Ejr0jTQ76ybE1j6XY7H23dJqSmjgrgnTnlTWQbjY#tonemapping) by Jorgen Herland, seems to explains a lot of the undertones of this thread

Title: Re: Tonemapping - Plz Halp
Post by: James Vella on 2020-08-19, 20:06:18
Thanks for sharing, to quote from Jorgen:

"However, this requires the linear render be converted to log first, to compress all the RGB values into a low dynamic range before the LUT is applied..."

I tend to agree. This is basically my findings on page 13 of this thread when comparing ACES to the Canon LUT. It was pretty close and much less hassle then the current ACES workflow.
Title: Re: Tonemapping - Plz Halp
Post by: cjwidd on 2020-08-19, 21:20:25
The suggestion is to convert the rendered image to log before applying the filmic LUT, BUT the Corona Renderer curve editor is too cumbersome to replicate the lin2log transfer function.

As a workaround - to that workaround (!) - the suggestion is to simulate the lin2log transfer function by adjusting the tonemapping options, e.g. contrast (5.0) and highlight compression (5.0).

Maybe it would be sufficient to create the lin2log curve in PS and then import into Corona Renderer curve editor to achieve the same effect(?) I tried to do this, but PS curve editor doesn't have bezier controls either lol
Title: Re: Tonemapping - Plz Halp
Post by: PROH on 2020-08-19, 22:04:18
Hi. No expert on this, so this might be a stupid question:
What's wrong with using the "Input LUT is in Log color space" checkbox together with an ACES LUT (i.e. "Filmic Very High Contrast")? Picture attached.
Title: Re: Tonemapping - Plz Halp
Post by: cjwidd on 2020-08-19, 23:11:23
What is the order of operations here, because I thought about this as well(?) Is a log transform being applied to the Filmic High Contrast LUT (what does that result in?) and then the image?
Title: Re: Tonemapping - Plz Halp
Post by: cjwidd on 2020-10-03, 07:41:31
Obviously this was a major point of discussion earlier in the thread, but having not reviewed many Fstorm renders at the time, I felt a little left out.

That being said, I cannot deny that on average the Fstorm renders I see just look more photographic. That's not meant to be a referendum on Corona Renderer, or FStorm, or meant to imply one renderer is superior, etc. - it's just an observation. I follow the FStorm FB group and the Corona Renderer gallery / Instagram on a more or less daily basis.

It's possible that observation is a sort of sampling bias with more users rendering with Corona Renderer than FStorm and maybe there is a concentration of expertise in the FStorm user base because more expertise is required to operate a renderer with less documentation, tutorials, outreach, etc.

The particular look of the two renderers is somehow noticeable though.
Title: Re: Tonemapping - Plz Halp
Post by: James Vella on 2020-11-26, 15:20:48
I thought id give this a shot with the new Vray5 workflow, following the manual:

- From Render Setup > Settings > Color management choose ACEScg
- Auto RGB primaries for VRayBitmap enabled
- textures converted to VrayBitmap
- diffuse images renamed with suffix _srgb.jpg
- gloss/normal maps renamed with suffix _lin_srgb.jpg

All text below this point is revised in the next post

VFB:

- Display Correction > None
- Create Layer > Filmic tonemap
- Tone mapping space > ACEScg
- log space enabled

Concepts:
- My thinking behind this experiment is similar to our previous conversation, trying to emulate very low light to high light without burn on either end.
- The reasoning behind working with None instead of sRGB in Display Correction is I want to work scene-linear instead of display-linear.
- I chose to work in log space since I noticed a little more breathing room with the tone mapping sliders, I dont have a technical explanation for this maybe someone else has a better understanding.
- I wanted to keep this experiment as simple as possible so I pushed the sliders until I could increase the shoulder strength to increase exposure and then work backwards to increase the contrast/gamma and experiment with the white point.
- The second last image is just adjusting the sliders to reach a happy medium.
- the last image is over exposure, what I would expect to see in lightroom (or on page 17 of this thread).

Interesting to hear your thoughts or if I missed something.
Title: Re: Tonemapping - Plz Halp
Post by: James Vella on 2020-11-27, 11:42:59
hmm it looks like I have compared apples to oranges. I revisited this with a different train of thought and I think this is heading in the right direction. You can ignore everything I said after "VFB:" in my previous post.

After reading the Maya manual on this it mentions you can use the filmic / AMPAS tonemap in replacement of the OCIO for this workflow. This didnt work for me but I found by removing the filmic tonemapping and replacing it with the OCIO for the transform I got the results I was expecting. This is only adjusting exposure stops.

You can download the scene here and investigate (3dsmax 2019): https://drive.google.com/file/d/1Oauy92VyHPNiGbeRhVHEMV1HR2ChyDm3/view?usp=sharing

edit:
artistically speaking you could do either or both depending on your pipeline. Comparing this to the original Corona renders there seems to be far less burnout in over exposed areas in my opinion.
Title: Re: Tonemapping - Plz Halp
Post by: cjwidd on 2020-11-28, 00:32:57
It seems like until we get true color management Jorgen Herland's approach (https://www.jorgenhdri.com/explained/?fbclid=IwAR0C9L795PY4h_jWsB3Ejr0jTQ76ybE1j6XY7H23dJqSmjgrgnTnlTWQbjY#tonemapping) is the simplest, most predictable(?)
Title: Re: Tonemapping - Plz Halp
Post by: Jpjapers on 2020-12-03, 23:05:31
Just curious, what are your main reasons for pursuing this pipeline? Is it to keep up with industry movement or are you finding much benefit from it in your CG pipeline?
I think over the past 5/6 years ive read similar threads and its been interesting seeing how the discussion changes and seeing how much better its understood each time but i think alot of people, myself included, would love to know how following colour managed workflow in this way actually helps you day-to-day.
Title: Re: Tonemapping - Plz Halp
Post by: hldemi on 2020-12-04, 11:10:36
Just curious, what are your main reasons for pursuing this pipeline? Is it to keep up with industry movement or are you finding much benefit from it in your CG pipeline?
I think over the past 5/6 years ive read similar threads and its been interesting seeing how the discussion changes and seeing how much better its understood each time but i think alot of people, myself included, would love to know how following colour managed workflow in this way actually helps you day-to-day.

I dont get why this topic now when tonemapping is being redone in Corona roadmap.
What would actually help is to include the community to test and intervene this development so that the new tonemapping is really what we need.
Title: Re: Tonemapping - Plz Halp
Post by: agentdark45 on 2020-12-04, 18:43:06
Just curious, what are your main reasons for pursuing this pipeline? Is it to keep up with industry movement or are you finding much benefit from it in your CG pipeline?
I think over the past 5/6 years ive read similar threads and its been interesting seeing how the discussion changes and seeing how much better its understood each time but i think alot of people, myself included, would love to know how following colour managed workflow in this way actually helps you day-to-day.

Ultimately for me it's to get better and more photographic renders "out of the box". Less fiddling with VFB sliders and cursing over blowouts, black crush, murky greys, wonky contrast/saturation, scrolling through LUTs e.t.c.
Title: Re: Tonemapping - Plz Halp
Post by: Jpjapers on 2020-12-11, 14:18:16
Just curious, what are your main reasons for pursuing this pipeline? Is it to keep up with industry movement or are you finding much benefit from it in your CG pipeline?
I think over the past 5/6 years ive read similar threads and its been interesting seeing how the discussion changes and seeing how much better its understood each time but i think alot of people, myself included, would love to know how following colour managed workflow in this way actually helps you day-to-day.

Ultimately for me it's to get better and more photographic renders "out of the box". Less fiddling with VFB sliders and cursing over blowouts, black crush, murky greys, wonky contrast/saturation, scrolling through LUTs e.t.c.

Thanks thats what i assumed :)
Title: Re: Tonemapping - Plz Halp
Post by: DustinMoore on 2020-12-17, 00:49:26



Even in this image, obviously with a lot of detail, I can tell that boat is fake.
(https://i.imgur.com/GMXygbD.jpg)

This is because thew artist didnt use the materials correctly. Tiling is wrong, reflection levels and sheer wrong material for the wood along the rim.
Title: Re: Tonemapping - Plz Halp
Post by: lupaz on 2021-01-21, 20:23:14
Got this image from the Fstorm facebook group.
I thought posting it here.

Title: Re: Tonemapping - Plz Halp
Post by: Juraj on 2021-01-21, 21:59:46
Great comparison. Would be nice to see it also with Filmic from latest Vray 5 VFB2.
Title: Re: Tonemapping - Plz Halp
Post by: cjwidd on 2021-01-21, 22:33:00
Got this image from the Fstorm facebook group.
I thought posting it here.
I follow the Fstorm FB group as well, but haven't seen this image. When was it posted?
Title: Re: Tonemapping - Plz Halp
Post by: Nejc Kilar on 2021-01-22, 11:25:53
Got this image from the Fstorm facebook group.
I thought posting it here.
I follow the Fstorm FB group as well, but haven't seen this image. When was it posted?

I think it was quite a while back. Like a couple of months at least. :\
Title: Re: Tonemapping - Plz Halp
Post by: lupaz on 2021-01-22, 16:13:15
Got this image from the Fstorm facebook group.
I thought posting it here.
I follow the Fstorm FB group as well, but haven't seen this image. When was it posted?

Sorry. I can't find it now.
I think it was Andrey's.

EDIT: Found it, in one of the comments in the thread below.
https://www.facebook.com/groups/FStormGroup/permalink/2456112348018502/
Title: Re: Tonemapping - Plz Halp
Post by: lolec on 2021-01-23, 00:05:49
Of course, Andrey has no incentive to make Corona look as good as possible. And in all fairness, Fstorm default looks more realistic than Corona default. No discussion about that.

However, improving corona in this particular scenario only takes a few seconds.

setting the saturation to -0.03 as discussed in this thread, gives a very natural and comparable result.

Let's hope the new tonemapping makes this even easier so we don't have to set even 1 parameter.

(https://i.imgur.com/jsNRVyR.jpg)
Title: Re: Tonemapping - Plz Halp
Post by: cjwidd on 2021-01-23, 00:30:45
lel nice +1
Title: Re: Tonemapping - Plz Halp
Post by: Juraj on 2021-01-25, 15:06:21
lol
Title: Re: Tonemapping - Plz Halp
Post by: piotrus3333 on 2021-06-12, 22:20:11
Great comparison. Would be nice to see it also with Filmic from latest Vray 5 VFB2.

you can emulate VRay's Filmic Hable defaults with this:
Highlight compress = 999 and lut:
Title: Re: Tonemapping - Plz Halp
Post by: piotrus3333 on 2021-06-14, 16:57:28
aces tone mapper from VRay.
same deal: HC999+lut
Title: Re: Tonemapping - Plz Halp
Post by: cjwidd on 2021-06-14, 17:06:17
moar plz +1
Title: Re: Tonemapping - Plz Halp
Post by: piotrus3333 on 2021-06-14, 17:17:50
moar plz +1

what else would you like to compare?

btw: as I haven't used Corona for a while - curves in Image Editor are resetting after I add a few points - is it just me or a known thing?
Title: Re: Tonemapping - Plz Halp
Post by: cjwidd on 2021-06-14, 17:21:29
btw: as I haven't used Corona for a while - curves in Image Editor are resetting after I add a few points - is it just me or a known thing?

I have not scene this bug before, best to record a short video of the issue and report to Max bug reporting (https://forum.corona-renderer.com/index.php?board=2.0) thread

what else would you like to compare?

I'll take literally any LUT that be used in Corona Renderer that might reasonable improve the tonemapping - yes that is vague, but as an artist, maybe there are some LUTs, like the ones you've already shared, that are often reliable / useful / etc.
Title: Re: Tonemapping - Plz Halp
Post by: piotrus3333 on 2021-06-14, 17:35:12
I'll take literally any LUT that be used in Corona Renderer that might reasonable improve the tonemapping - yes that is vague, but as an artist, maybe there are some LUTs, like the ones you've already shared, that are often reliable / useful / etc.

what is there to improve? curve editor looks quite nice for sure, you can resize the window and be as precise as you need I guess.
Title: Re: Tonemapping - Plz Halp
Post by: piotrus3333 on 2021-06-16, 11:24:50
ok. one more lut. although this one is more of a switch.
idea is: linear >> log >> adjust with curves.
make curve editor window bigger so you get nice granular control and see the histogram detail. set your white point, set your black point and just go to town. your own flavour of "filmic" in "seconds".

load the lut file (attached) with Input LUT is in log color space on. (this is basically CineonLog)
Title: Re: Tonemapping - Plz Halp
Post by: maou42 on 2021-08-28, 00:10:33
Hi Martin

Thanks for the LUTs.

I can not find the option to load a LUT as a log...

Mat
Title: Re: Tonemapping - Plz Halp
Post by: Nejc Kilar on 2021-08-30, 09:14:09
Hi Martin

Thanks for the LUTs.

I can not find the option to load a LUT as a log...

Mat

Hey!

You should find that option in the Render Settings under the Camera menu :)
Title: Re: Tonemapping - Plz Halp
Post by: davemahi on 2021-10-29, 16:02:40
This is getting to the point where not having ACES in Corona will make us stop using it.
We are getting asked by compositors and studios to be workign in this workflow now. So if Corona
is not going to have this in the near future our studio will be forced to move on. Now that could be Vray,
Red Shift or Fstorm. I would say to the corona Devs, do not become like Autodesk where it takes years to get
industry standards into the software.
Title: Re: Tonemapping - Plz Halp
Post by: James Vella on 2021-10-29, 16:58:33
This is getting to the point where not having ACES in Corona will make us stop using it.
We are getting asked by compositors and studios to be workign in this workflow now. So if Corona
is not going to have this in the near future our studio will be forced to move on. Now that could be Vray,
Red Shift or Fstorm. I would say to the corona Devs, do not become like Autodesk where it takes years to get
industry standards into the software.

I didnt think FStorm supported aces? I thought Fstorm was wide gamut (similar to Corona). OCIO would be useful I suppose for plate matching but you can still render 32bit images and composite/tonemap from there. Am I missing something?
Title: Re: Tonemapping - Plz Halp
Post by: davemahi on 2021-10-29, 18:55:55
You may be right about FStorm. But when we are working with other pipelines now and the first thing we are asked is are we working in that profile,
we have to move with the industry. Don't get me wrong, Corona is a great render engine, but we have to move with the industry.
I believe that was the logic behind the new corona material. The old shader is great, but now the physical material is now industry standard. I guess what I don't get is the Devs not jumping ahead of the game here? It's not like it is something that is going to go away.

Title: Re: Tonemapping - Plz Halp
Post by: cjwidd on 2021-10-29, 19:00:40
Pretty sure it's due to limitations in Max, at least up until OCIO support becomes available.
Title: Re: Tonemapping - Plz Halp
Post by: GraceKellyPerfect on 2021-11-04, 21:57:01
Pretty sure it's due to limitations in Max, at least up until OCIO support becomes available.
I believe they (3ds Max team)  added OCIO support in their roadmap somwhere in April 2020, God only knows how long long it will take them to finally launch it. There should be one more update this year so there is hope but I think it is more likely it will come with 2023 version.
Title: Re: Tonemapping - Plz Halp
Post by: cjwidd on 2021-11-04, 22:24:46
Someone shared a Vray LUT on this thread that has really helped me a lot - not the same as full ACES support, but helpful.
Title: Re: Tonemapping - Plz Halp
Post by: piotrus3333 on 2021-11-30, 14:47:05
Someone shared a Vray LUT on this thread that has really helped me a lot - not the same as full ACES support, but helpful.

Isn't Corona's wide gamut rgb pretty much as wide as acescg?
Isn't the ability to tone map the image however you like better than one fixed curve?

what is the expectation here?

I understand those that suddenly found themselves being a part of pipeline requiring aces but everybody else?
Title: Re: Tonemapping - Plz Halp
Post by: lupaz on 2021-11-30, 17:22:11
Someone shared a Vray LUT on this thread that has really helped me a lot - not the same as full ACES support, but helpful.

Isn't Corona's wide gamut rgb pretty much as wide as acescg?
Isn't the ability to tone map the image however you like better than one fixed curve?

what is the expectation here?

I understand those that suddenly found themselves being a part of pipeline requiring aces but everybody else?

My only expectation is that colors don't get so saturated on hotspots. I believe that was part of the conversation here on this thread. For example, when the sun hits wood you get a yellowish halo around the white area. Yes, you can lower the overall saturation, but you're affecting the entire image. Reinhardt or crunching the whites don't seem to work as if you were working with an HDR. I may be wrong and I'm far from an expert in the subject.
Title: Re: Tonemapping - Plz Halp
Post by: piotrus3333 on 2021-12-01, 01:57:42
desaturation might be a bit heavy but let me know how this one works for you. HC+lut.
Title: Re: Tonemapping - Plz Halp
Post by: cjwidd on 2021-12-01, 04:43:34
Hey @Piotrus333 the Vray LUT you shared awhile back has really been helpful for me - thank you so much for sharing!
Title: Re: Tonemapping - Plz Halp
Post by: piotrus3333 on 2021-12-01, 11:58:25
Hey @Piotrus333 the Vray LUT you shared awhile back has really been helpful for me - thank you so much for sharing!

sure thing. you’re welcome. VRay Hable or ampas lut?
Title: Re: Tonemapping - Plz Halp
Post by: muoto on 2021-12-01, 13:19:04
Hello Piotrus,

how did you generated those lut's ? any specific software ?

thanks!
Title: Re: Tonemapping - Plz Halp
Post by: piotrus3333 on 2021-12-01, 13:59:11
Hello Piotrus,

how did you generated those lut's ? any specific software ?

thanks!

affinity photo for ipad, fusion. use whatever you have. photoshop?
Title: Re: Tonemapping - Plz Halp
Post by: cjwidd on 2021-12-02, 02:16:57
Hey @Piotrus333 the Vray LUT you shared awhile back has really been helpful for me - thank you so much for sharing!

sure thing. you’re welcome. VRay Hable or ampas lut?

mP_Reinhard2VRayAMPAS and mP_Reinhard2VRayFilmic have both been great to work with.

Do you have mP_Reinhard2VRayAMPAS_desatHL2.3dl as a .cube - I guess it doesn't matter for Corona Renderer VFB(?)
Title: Re: Tonemapping - Plz Halp
Post by: piotrus3333 on 2021-12-02, 10:00:46
format does not matter. I’m glad you found it useful.
Title: Re: Tonemapping - Plz Halp
Post by: dj_buckley on 2021-12-02, 10:41:56
desaturation might be a bit heavy but let me know how this one works for you. HC+lut.

This is exactly what I've been looking for so thank you.
Title: Re: Tonemapping - Plz Halp
Post by: piotrus3333 on 2021-12-02, 17:31:36
This is exactly what I've been looking for so thank you.

enjoy.
and in case this is not enough then FStorm desaturates highlights even more:
Title: Re: Tonemapping - Plz Halp
Post by: dj_buckley on 2021-12-02, 20:03:00
Awesome, is this the same as the hardcoded LUT that FStorm uses as a base?
Title: Re: Tonemapping - Plz Halp
Post by: piotrus3333 on 2021-12-02, 20:46:08
Awesome, is this the same as the hardcoded LUT that FStorm uses as a base?

heh, no. not the same. Fstorm’s curve has a few adjustable parameters and is not very straightforward. this is fairly decent aproximation of the defaults. you can send low res raw exr from corona and I can show you the difference. this lut relies on reinhard starting point so images with lower dynamic range get more noticable difference.
Title: Re: Tonemapping - Plz Halp
Post by: lupaz on 2021-12-02, 20:53:13
Thank you Piotrus.

I like Reinhard2VrayAMPAS, which seems to be very similar to Dubcat's Cannon 5D Mark I.

In my opinion Reinhard2FstormDefaults is way too saturated.
Title: Re: Tonemapping - Plz Halp
Post by: dj_buckley on 2021-12-02, 21:05:30
Thank you Piotrus.

I like Reinhard2VrayAMPAS, which seems to be very similar to Dubcat's Cannon 5D Mark I.

In my opinion Reinhard2FstormDefaults is way too saturated.

Couldn't agree more, Reinhard2VRayAMPAS is the one I keep going back too, it's almost perfect.  Even the 5D one you mention I find just that little bit too saturated and contrasty.

Edit: Ignore that bit about the 5D one, I was getting mixed up.  Yes they're both incredibly similar.  The 5D one has a little more punch to it
Title: Re: Tonemapping - Plz Halp
Post by: cjwidd on 2021-12-02, 21:13:45
I've learned *A LOT* from Dubcat, so no offense, but I feel like my encounter with his Photographic LUTs early on while learning Corona Renderer, really led me astray. The 5D Mark 1 and 5DS LUTs produce a much more natural look, which is probably a better starting point when pursuing an un-edited photographic look.
Title: Re: Tonemapping - Plz Halp
Post by: cjwidd on 2021-12-02, 23:56:03
@piotrus3333 are you sure that the VFB doesn't render .cube vs .3dl differently? It looks like there is some color burn, or something, using the .3dl in VFB LUT, compared to .cube(?) Testing mP_Reinhard2FstormDefaults_v1.3dl.
Title: Re: Tonemapping - Plz Halp
Post by: piotrus3333 on 2021-12-03, 00:09:59
one more.
since ampas seems to be the winner - this is more precise version of VRayAMPAS lut. check input LUT is in Log color space and leave HC at default (or you can actually use it to move the white point up or down).
Title: Re: Tonemapping - Plz Halp
Post by: piotrus3333 on 2021-12-03, 00:23:28
@piotrus3333 are you sure that the VFB doesn't render .cube vs .3dl differently? It looks like there is some color burn, or something, using the .3dl in VFB LUT, compared to .cube(?) Testing mP_Reinhard2FstormDefaults_v1.3dl.

this one is quite saturated. format shouldn't matter but I've never checked that in Corona to be honest. first luts I posted were linear in 3dl format and 2.2 in cube. recent ones are all 2.2 in 3dl. corona does backflips with gamma in vfb.
Title: Re: Tonemapping - Plz Halp
Post by: dj_buckley on 2021-12-03, 10:27:34
I've learned *A LOT* from Dubcat, so no offense, but I feel like my encounter with his Photographic LUTs early on while learning Corona Renderer, really led me astray. The 5D Mark 1 and 5DS LUTs produce a much more natural look, which is probably a better starting point when pursuing an un-edited photographic look.

Yep, it's the 5DS one I've been testing actually not the Mark 1.  If you're albedos stay within the stricter ranges, it produces a really nice starting point.
Title: Re: Tonemapping - Plz Halp
Post by: Bjoershol on 2021-12-03, 14:08:50
I've learned *A LOT* from Dubcat, so no offense, but I feel like my encounter with his Photographic LUTs early on while learning Corona Renderer, really led me astray. The 5D Mark 1 and 5DS LUTs produce a much more natural look, which is probably a better starting point when pursuing an un-edited photographic look.

Yep, it's the 5DS one I've been testing actually not the Mark 1.  If you're albedos stay within the stricter ranges, it produces a really nice starting point.

Can these LUTs be found anywhere for download? Would love to test them out. :)
Title: Re: Tonemapping - Plz Halp
Post by: dj_buckley on 2021-12-04, 11:24:25
They're in this thread - the 5DS one I have is attached
Title: Re: Tonemapping - Plz Halp
Post by: Bjoershol on 2021-12-04, 20:19:49
Thank you, appreciate it. :)
Title: Re: Tonemapping - Plz Halp
Post by: piotrus3333 on 2021-12-06, 14:41:42
My only expectation is that colors don't get so saturated on hotspots. I believe that was part of the conversation here on this thread. For example, when the sun hits wood you get a yellowish halo around the white area. Yes, you can lower the overall saturation, but you're affecting the entire image. Reinhardt or crunching the whites don't seem to work as if you were working with an HDR. I may be wrong and I'm far from an expert in the subject.

hello again.
regarding the burning need for ACES in Corona - at least for those not in film/vfx - please spare a moment and have a look at these two. the difference is internal color space: ACEScg vs sRGB. so wide gamut vs, well, narrower gamut. Corona's internal is wide from day one (remember this one from 2014: "wow, Corona has such a nice natural lighting").

so how do these two look?
Title: Re: Tonemapping - Plz Halp
Post by: cjwidd on 2021-12-06, 22:46:01
Tough, they both look good - obviously the blue tone shadow stands out in the 'ACES_test_F' version, and the props look better in 'ACES_test_F', but the strong blue tone on the white shader ball (upper left) is very noticeable.
Title: Re: Tonemapping - Plz Halp
Post by: cjwidd on 2021-12-07, 02:51:56
@piotrus3333 do you have LUTs for these, I'd like to test them out(?)
Title: Re: Tonemapping - Plz Halp
Post by: piotrus3333 on 2021-12-07, 09:27:34
@piotrus3333 do you have LUTs for these, I'd like to test them out(?)

these are as plain as possible. just raw srgb and acescg with tone mapping. ampas curve for srgb and default srgb transform for acescg. so pretty much the same curves. fancy lens to make them look a bit less synthetic.
Title: Re: Tonemapping - Plz Halp
Post by: piotrus3333 on 2021-12-07, 11:23:03
@piotrus3333 do you have LUTs for these, I'd like to test them out(?)

this is output from CIE with mP_LogCorona2VRayAMPAS.3dl and 1 stop of exposure correction (I did the same in VRay - srgb raw was brighter than acescg).
conversion was: VRay's raw acescg >> srgb >> CIE >> -1 exp >> log lut

edit: I mean VRay's raw acescg >> lin srgb >> CIE (-1 exp, log lut)
Title: Re: Tonemapping - Plz Halp
Post by: piotrus3333 on 2021-12-07, 12:09:02
apologies, forgot about 2.2 >> srgb.
corrected E and F from CIE (rough 2.2 >> srgb done in photoshop).
Title: Re: Tonemapping - Plz Halp
Post by: burnin on 2021-12-07, 22:46:57
For some finer orientation around color spaces, here's an an excerpt from Jorgen HDRI's comparative study on digital color, shared over @ "ACES for CGI" Discord:
Quote
I decided to test TCAM v2 today after reading this server. Based on Chris' color sweep tests it looks like it handles color mapping better than the ACES color transform (I'm sorry for butchering the nomenclature). My hope is to find a solution that provides me with the most accurate colors based on my own workflow and available hardware/software.

This test is an s-log2 shot (not CGI, I'm sorry Jin), which I had to store in a different log format (ACEScc), since the TCAM OCIO-config doesn't include s-log2 specifically. Also, I'm comparing the TCAM sRGB output to the ACES rec.709 output, since the ACES sRGB output had way more contrast and crushed blacks than rec.709, compared to TCAM sRGB output.


Dislaimer
I tried making these comparisons a gif, but really, that's a stupidly bad idea. So instead, here's a bunch of PNGs you can open in a browser and tab between to see the difference between how the different configurations handles the input colors and dynamic range.


(https://dl.dropboxusercontent.com/s/ebprr519paay042/frame1_aces.png)

(https://dl.dropboxusercontent.com/s/099oak0490zhx1v/frame1_tcam.png)
Quote
Let's just say these daffodils are orange IRL, very much like what TCAM is producing, not neon yellow like what ACES does.


PS
What I want to convey is, first a proper IRL reference must be established and only after a search for best CGI practice can commence. 
Title: Re: Tonemapping - Plz Halp
Post by: piotrus3333 on 2021-12-08, 00:05:36

PS
What I want to convey is, first a proper IRL reference must be established and only after a search for best CGI practice can commence.

heh, and I was going for something simpler like: there is nothing wrong with tone mapping in Corona.
Title: Re: Tonemapping - Plz Halp
Post by: piotrus3333 on 2022-02-09, 14:06:12
more tone mapping options:
https://forum.corona-renderer.com/index.php?topic=35578.0