Author Topic: Tonemapping - Plz Halp  (Read 115810 times)

2020-05-07, 19:16:09
Reply #285

Designerman77

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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.





2020-05-07, 19:36:15
Reply #286

twoheads

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2020-05-08, 12:23:48
Reply #287

cjwidd

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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.
  • Corona renders use Dubcat's Fstorm 0.30 contrast LUT at 0.90 opacity, EV = -.75, sharpening (3.0, 0.05, 0.25), other settings at default, no bloom
  • Fstorm renders use default settings
  • Grey is 186,186,186; 0 glossiness
  • One light source; interior HDRI from Dubcat.


« Last Edit: 2020-05-08, 21:38:19 by cjwidd »

2020-05-08, 14:45:09
Reply #288

bluebox

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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.
« Last Edit: 2020-05-08, 14:49:01 by bluebox »

2020-05-08, 15:06:06
Reply #289

Designerman77

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...


Hahaaaaa... LOOOOOL !!!!!
You made my day. :)

2020-05-08, 15:53:41
Reply #290

lupaz

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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.


2020-05-08, 15:56:30
Reply #291

hldemi

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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.



2020-05-08, 16:06:44
Reply #292

PROH

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@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 :)

2020-05-08, 16:57:27
Reply #293

dfcorona

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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.

2020-05-08, 17:23:37
Reply #294

Designerman77

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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.

2020-05-08, 17:25:55
Reply #295

Jpjapers

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@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.

2020-05-08, 17:26:35
Reply #296

Designerman77

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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...
« Last Edit: 2020-05-08, 17:42:05 by Designerman77 »

2020-05-08, 17:34:02
Reply #297

Jpjapers

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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.

2020-05-08, 17:45:49
Reply #298

Designerman77

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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.

2020-05-08, 17:47:54
Reply #299

aldola

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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.