Chaos Corona Forum
Chaos Corona for 3ds Max => [Max] Corona Goodies - User Contributions => Topic started by: piotrus3333 on 2023-09-13, 12:36:19
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https://github.com/sobotka/AgX/discussions/3 (https://github.com/sobotka/AgX/discussions/3)
edit: more complete set of AgX luts for Corona in post #8.
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Great setup thanks. Works really nicely to achieve soft renders. I found that adding a Tone Curve is useful to bring back some contrast.
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Saw it on a blender video, will try those luts ! Thx!
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quick look at ACESOT vs AgX punchy luts:
sample used - env map by Greg Zaal
https://polyhaven.com/a/shanghai_bund
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or maybe compare this with AgX for more fair comparison (update to aces1.3):
sample used - env map by Greg Zaal
https://polyhaven.com/a/shanghai_bund
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While they both have issues with blowout areas, from my perspective I like the AcesOT more than the AGXLuts. The AGX looks washed out to me, losing a lot of contrast. Maybe I'm just used to how modern phones adjust photos to look nice and punchy.
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While they both have issues with blowout areas, from my perspective I like the AcesOT more than the AGXLuts. The AGX looks washed out to me, losing a lot of contrast. Maybe I'm just used to how modern phones adjust photos to look nice and punchy.
contrast is a secondary element here. AgX Appearance Punchy is just one of demo looks supplied by the author. you can make it as contrasty as you need it to be.
it is all about handling of hot saturated colours (Corona didn't even bother with updating acesot but I guess it's a different discussion)
acesot vs agx with matched contrast attached:
edit:
sample used - env map by Greg Zaal
https://polyhaven.com/a/shanghai_bund
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Interesting results with AGX. Could you export the lut's for the other contrasts looks as well ?
thanks!
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mP_Corona_AgX.zip
edit:
looks punchy and golden are based on AgX Base with power, slope, offset and saturation transforms. Base is created from logarithmic encoding Kraken with 1D lut supplied with original AgX ocio config: https://github.com/sobotka/AgX (https://github.com/sobotka/AgX)
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actually, would even be better to have OCIO in corona, no ?...
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^^Yes... more on & in-depth.
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AgX Appearance Punchy is just one of demo looks supplied by the author. you can make it as contrasty as you need it to be.
I found out about Agx a few weeks ago and I tried to modify or make new looks to better approximate the contrast of the default sRGB. I tried it in blender, even though I don't use blender but it was easier to test it there.
And the more I increased the contrast, the more I feel like I was "breaking" the Agx. But at the same time there are many ways you can manipulate the image in OCIO so maybe I did it wrong ?
- !<Look>
name: Punchy
process_space: AgX Base
description: .......
transform: !<CDLTransform> { power: [ 1.3, 1.3, 1.3 ], sat: 1.2 }
- !<Look>
name: Punchy Full
process_space: AgX Base
description: Trying to increase the contrast, this one seems ok
transform: !<CDLTransform> { power: [ 1.35, 1.35, 1.35 ], sat: 1.4 }
punchy double : this one is more contrasty but in certain situation maybe negates a bit of the AGX advantages ??
- !<Look>
name: Punchy Double
process_space: AgX Base
transform: !<GroupTransform>
children:
- !<CDLTransform> { power: [ 1.35, 1.35, 1.35 ], sat: 1.2 }
- !<CDLTransform> { slope: [1.1, 1.1, 1.1], power: [ 1.1, 1.1, 1.1 ], sat: 1.2 }
- !<ExponentTransform> {value: [1.1, 1.1, 1.1, 1]}
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AgX Appearance Punchy is just one of demo looks supplied by the author. you can make it as contrasty as you need it to be.
I found out about Agx a few weeks ago and I tried to modify or make new looks to better approximate the contrast of the default sRGB. I tried it in blender, even though I don't use blender but it was easier to test it there.
And the more I increased the contrast, the more I feel like I was "breaking" the Agx. But at the same time there are many ways you can manipulate the image in OCIO so maybe I did it wrong ?
- !<Look>
name: Punchy
process_space: AgX Base
description: .......
transform: !<CDLTransform> { power: [ 1.3, 1.3, 1.3 ], sat: 1.2 }
- !<Look>
name: Punchy Full
process_space: AgX Base
description: Trying to increase the contrast, this one seems ok
transform: !<CDLTransform> { power: [ 1.35, 1.35, 1.35 ], sat: 1.4 }
punchy double : this one is more contrasty but in certain situation maybe negates a bit of the AGX advantages ??
- !<Look>
name: Punchy Double
process_space: AgX Base
transform: !<GroupTransform>
children:
- !<CDLTransform> { power: [ 1.35, 1.35, 1.35 ], sat: 1.2 }
- !<CDLTransform> { slope: [1.1, 1.1, 1.1], power: [ 1.1, 1.1, 1.1 ], sat: 1.2 }
- !<ExponentTransform> {value: [1.1, 1.1, 1.1, 1]}
- !<ColorSpace>
name: mP aces contrast
family: Imagery
equalitygroup: ""
bitdepth: unknown
description: mP aces contrast
isdata: false
allocation: uniform
from_scene_reference: !<GroupTransform>
children:
- !<ColorSpaceTransform> {src: Linear BT.709, dst: AgX Log (Kraken)}
- !<FileTransform> {src: AgX_Default_Contrast.spi1d}
- !<FileTransform> {src: mP_aces_contrast_2.3dl}
lut would be a better way to add your look. this is simple way to do that (with just additional lut on top). one spi1d lut would be more precise.
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Hi. You could try this https://github.com/EaryChow/AgX
It is a version of AgX that has some additions: Includes and handles wide color space gamuts, preserves hue better across the range of intensities, has contrast looks made specifically for AgX
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Thank you Piotrus.
I like Kraken.
What's good about ACESOT that this one doesn't seem to help with is with highlights and the color shift in the hue of highlight gradients.
Good to have though.
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Thank you Piotrus.
I like Kraken.
What's good about ACESOT that this one doesn't seem to help with is with highlights and the color shift in the hue of highlight gradients.
Good to have though.
sounds like something is not right with the setup.
screenshoot?
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Here you go.
The higher I go with AgX the more pinkish hues I get.
EDIT: with Kraken it's better than with base.
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Thank you Piotrus.
I like Kraken.
What's good about ACESOT that this one doesn't seem to help with is with highlights and the color shift in the hue of highlight gradients.
Good to have though.
also - is this what is good about ACES OT ??:
https://forum.corona-renderer.com/index.php?action=dlattach;topic=40952.0;attach=188097
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Here you go.
The higher I go with AgX the more pinkish hues I get.
EDIT: with Kraken it's better than with base.
you need 2 luts: A and B. B needs “logarythmic” option on. edit: both at 1.0 opacity:
https://forum.corona-renderer.com/index.php?action=dlattach;topic=40952.0;attach=188022
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Here you go.
The higher I go with AgX the more pinkish hues I get.
EDIT: with Kraken it's better than with base.
you need 2 luts: A and B. B needs “logarythmic” option on. edit: both at 1.0 opacity:
https://forum.corona-renderer.com/index.php?action=dlattach;topic=40952.0;attach=188022
Sorry! I missed that screenshot. I went straight to your post #8. I'll try this setup.
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It's great. Like the guy in the video said, it gives you something to work with. Definitely needs contrast and saturation, but as a starting point is very good.
Excellent video this one:
^^Yes... more on & in-depth.
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actually, the trick of the two luts, one for the color matrix (especially for controling the "above 1" color values), one for the curve is pretty interesting.
i made a few of my own for the matrix and for the 1dlut curve, maybe less scientifically correct as the one of piotrus, but the results are nice !
thanks for the tip !
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actually, the trick of the two luts, one for the color matrix (especially for controling the "above 1" color values), one for the curve is pretty interesting.
i made a few of my own for the matrix and for the 1dlut curve, maybe less scientifically correct as the one of piotrus, but the results are nice !
thanks for the tip !
unfortunately it's impossible to be really precise with luts in Corona:
https://forum.corona-renderer.com/index.php?topic=40988.0 (https://forum.corona-renderer.com/index.php?topic=40988.0)
- you can (probably, I have not tried) improve my matrix lut by creating one that will cover 0 - 16.something float range
- 1dlut as the second lut is the right way to go (in that case look lut can be the third one, again - probably - would be still precise enough)
edit: in general, considering ACES OT not being updated with important aces fixes from 2021, and post being done in CIE, AgX is great option for Corona users.
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Hello, do you need to add OCIO configuration environment variables in the corona renderer?
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Hello, do you need to add OCIO configuration environment variables in the corona renderer?
Hi, sorry, but I am not sure what exactly you mean, and also there is no need to report your own posts to moderators. :)
Can you please explain what kind of help or answer you are seeking?
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Hello, I need the moderator's answer because in addition to adding lut, do I need to load the ocio environment variable of AGX when setting up AGX?
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Please note that you should only report posts if you need some help from forum moderators - for example if you posted your forum thread in a wrong forum section or if you would like to report spam.
Regarding the environment variable option - it is currently not supported. If you set Corona as your renderer and select the "OCIO - Environment Variable" you will see an error message from Corona.
See: https://support.chaos.com/hc/en-us/articles/20283060170257
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Hello, do you need to add OCIO configuration environment variables in the corona renderer?
no, just luts.
created with legacy gamma setup in 3dsMax 2024 in mind.
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Thank you for your answers! Is it useful to add ocio Vray renderer to environment variables?
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Thank you for your answers! Is it useful to add ocio Vray renderer to environment variables?
VRAY_VFB_OCIO - no.
OCIO - yes, if you are using only/mostly one ocio config.
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Thank you for your answers!
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More of AgX by Troy Sobotka - this time his Resolve version of it (quite different) married with a film look from Arri:
https://forum.corona-renderer.com/index.php?topic=41947.msg223544#msg223544
note: it does require a string option to turn off VFB's sRGB view lut so might be a bit more cumbersome to use.
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But when importing exr's from corona to fusion, there is a extra gamma applied (1.2?) because the image in fusion is much darker than in VFB. And then you need to specify the float gamma thing to have the same result in vfb and fusion ?
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But when importing exr's from corona to fusion, there is a extra gamma applied (1.2?) because the image in fusion is much darker than in VFB. And then you need to specify the float gamma thing to have the same result in vfb and fusion ?
AgX luts for Corona from this thread are made for default Corona behaviour regarding gamma transforms in VFB. by default VFB has hidden 2.2 transform after the TONE MAPPING stack and effects. it also has hidden gamma transforms in every LUT operator.
if you are using my AgX luts there is no need for string option changing VFB's gamma behaviour ("float gamma thing").
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But when importing exr's from corona to fusion, there is a extra gamma applied (1.2?) because the image in fusion is much darker than in VFB. And then you need to specify the float gamma thing to have the same result in vfb and fusion ?
AgX luts for Corona from this thread are made for default Corona behaviour regarding gamma transforms in VFB. by default VFB has hidden 2.2 transform after the TONE MAPPING stack and effects. it also has hidden gamma transforms in every LUT operator.
if you are using my AgX luts there is no need for string option changing VFB's gamma behaviour ("float gamma thing").
Wait, so for any LUTs from outside Corona install we need either the string option or a gamma operator @0.45 before the LUT? I remember trying some LUTs from other sources but gave up thinking they were not the right type.
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Wait, so for any LUTs from outside Corona install we need either the string option or a gamma operator @0.45 before the LUT? I remember trying some LUTs from other sources but gave up thinking they were not the right type.
I do not know the story behind luts from Corona installer but, in general - yes - to have a lut do what it is supposed to do in Corona VFB you need gamma transform operator (1/2.2).
I guess the story why it all works like that is long forgotten as the support was unable to point me to the simple solution - the string option for adjusting VFB gamma. I dug it out from an old 2015 post.
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ok, so at least we know that it used to work as expected for a brief moment:
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would anyone have a nuke layout that would work creating LUT's that would look similar in Nuke as in Corona Vfb ?
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Hello, I just saw this video on YouTube which deals with a so-called new tone mapping for Blender "he Khronos PBR Neutral Tone Mapper" (
) which seems to have the advantages of AGX without its disadvantages (lack of contrast and saturation depending on everyone's tastes). I have the impression that the combo of AGX MATRIX + AGX PUNCHY (+ contrast if necessary) is close compared to the combination AGX BASE + AGX KRAKEN + AGX DEFAULT CONTRAST.
I'm really uneducated about these issues so I was wondering what you thought about it.
Thanks in advance
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AgX in the form of luts from this thread is not the same AgX you have in Blender. There are three different versions of AgX - the one I uploaded is based on the original idea from Sobotka. it does not shift hues like the Blender 4 version. it is also made with BT709 primaries (what you would colloquially call srgb primaries) in mind.
agx matrix + punchy is, well, more punchy than agx matrix + kraken + default contrast. default contrast is called base look in original AgX ocio configuration. you can replace default contrast lut with your own curve or add colour grading lut on top of Kraken. punchy look if I remember correctly is just gamma adjustment - just a simple sample look, nothing to stick with. so this AgX basically will require your personal input in regards to final contrast.
it is possible than some other, preset based, display transform would be better suited for use in Corona: for example RED display transform consists of 16 combinations of 4 levels of contrast and 4 different highlight roll off strengths.
Khronos PBR Neutral Tone Mapper - I think they are trying to solve issues with colour reproduction for some quite specific cases. does any image in the video look natural to you? instead of rendering in wider gamut space and using some tried and tested colour science (from camera manufacturers for example) they are fiddling with display transform alone. BT709 colour space is too tiny to describe all real life colours - look at professional cameras: at least BT2020.
EDIT: ok, so this is indeed designed specifically for e-commerce. very different beast, very different needs. not for us.
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Thank you very much for your answer Piotrus. This clarifies these tone mapping things that are still confusing for me
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Another example of using AgX:
Resolve AgX version (DCTL) married to look from famous ARRI K1S1 lut.
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Hi Marcin, folks/devs,
We are typically using your fantastic AGX ToneMapping instead of ACES for almost everything these days, from this method, as it seems to have a much more pleasant and predicable rolloff for the highlights while preserving contrast and colour. The issue we're facing is that it doesn't seem to work properly with ToneMapControl when you set it to not affect the map. It seems to affect the exposure and crush certain tones and mess around with the contrast. I see there's a warning for this on the corona website "While the Corona Tonemap Control Map works fine most of the time, there are some special cases where it may fail, for example: using some LUTs, using extreme tone mapping operator values, setting the Contrast value to zero."
- Is there any workaround for this to get 1:1 result with the underlying map, like we get with ACES workflow?
- Is there a simplified single-LUT version of this we can use, which may or may not help?
Some notes:
- corona 11 HF 2, max 2024
- base map is an SRGB photo loaded into coronabitmaploader, zero colourcorrection, just the pure map
- it's then piped into tonemapcontrol with all the checkboxes disabled
- using AGX workflow method from here: https://forum.corona-renderer.com/index.php?topic=40952.0 - it results in 2 x LUTS being loaded into the coronacamera tonemapoverride. It's the second (lower) of the two LUTs that's breaking things (or rather being broken by the tonemapcontrol). And I believe we have the correct Logarithmic settings
- contrast is at 1.0, or 1.5 it doesn't matter (but it's not at 0.0 FYI, which we know can break things)
- we're aware of the IR tone mapping bug where you need to re-start the IR each time you affect things like exposure, tone mapping, LUTS etc. which we've done, so this isn't the issue (although devs, any news on a fix for this? it's very annoying and easy to forget!). It happens also in production rendering.
Example below:
(https://i.imgur.com/peWAH4N.jpeg)
Thanks for any help!
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@alexyork
skip the Corona Tonemap Control and just transform the backplate into your rendering space, linear rec709 in this case.
for this you need to reverse the AgX Punchy display transform. lin rec709 backplate will get back to AgX Punchy via frame buffer corrections. if you need to colour correct the backplate in Max do it in lin rec709 so its nice and tidy.
you need the original AgX ocio config from Troy Sobotka: https://github.com/sobotka/AgX
attached screenshot shows conversion done with VRayOCIO node, you can do this with Affinity/Photoshop/whatever else. 3dsMax 2024 setup with this AgX OCIO file should be able to convert it too.
there will be slight differences as luts I made ale limited in precision by Corona's cineon log conversion in lut layer.
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you can actually also try these luts. made for Vantage so you will always end up with transfer function difference srgb vs 2.2.
I also never tested Corona's linear option in lut layer so no guaranties.
instead of log - use Reinhard curve (h compression 999 in Corona) - should be more precise compared to old double lut setup.
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Ok awesome... ! Thank you. A lot to digest and figure out here so I might fire you some DMs when I get time to implement and test.
Cheers,
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Ok awesome... ! Thank you. A lot to digest and figure out here so I might fire you some DMs when I get time to implement and test.
Cheers,
sure, no worries.