ACES with 3ds max

[JulianD]

HDRI: In = Utility – linear – sRGB. Out = AcesCG
TextureDiffuseBitmaps: In = Utility – sRGB – texture. Out = AcesCG
Data maps (normal, gloss, Displace etc): In = Raw. Out = AcesCG

I would prefer the following expressions to prevent any confusion:
Linear sRGB: In = Utility – linear – sRGB. Out = AcesCG
2.2 sRGB: In = Utility – sRGB – texture. Out = AcesCG

By the way I haven't converted any data maps for my part. Should give it a try to see what would come up
edit: I just tried with a displace map in Linear sRGB exr file: I just plugged it in the displacement map slot of a vraymtl and made 2 renders: one with and one without a vrayOCIO (in: Raw, out: acescg): I don't post a comparison because there is absolutely no changes.
edit2: tried with a reflect map as well: same result. I don't know what <in:Raw out:AcesCG> really does I never used it before, but to me it's a simple linear conversion where no values are shifted, so the conversion is useless.

Also therefore i would assume we could only usb Srgb display in the VFB OCIO section? Not Rec709/Rec2020 for example, as we have set our texture map OCIO inputs to read our textures/hdri's etc as srgb initially. Or does it not matter?

Funny, we had this discussion a few message ago. Actually you can use any of the displays available but the best choice for you might be the colorspace of your final monitor/projector/tv.
Setting up your textures as sRGB doesn't mean you have to stay in that colorspace until the end You set up sRGB textures because they are sRGB textures, that's all. There is no real link between the textures' colorspace in entry and the display's colorspace in exit since there's a big ACES converter in the middle.

[JulianD]

@^Lele^: Yes we have a nice green and red bounce of the boxes, I agree.

I created a little script that switch from a "beta ACES workflow" to a "old sRGB workflow", no need to go over all the textures and parameters.. It's way faster to try things out now.





Then I made a few more tests :





A close-up:




We definitely have more colors on the left; some bluish colors are popping up, the green and yellow seem stronger as well. ACES is also a bit more contrasty but it doesn't blow up the highlight as sRGB will do, which is nice (the plane is grey 50% for both render).



Still I wasn't quite satisfied with the results. When I looked at the close-up I really prefered the left one (ACES) there is no doubt, but when I looked at the first comparison image I don't know why but the sRGB looks more "traditional" to me. It's hard to explain and maybe it is because we got used to the vanish color ? Maybe it's a bit closer to a log render so it "feels" cinema ? The ACES shadows looked clearly a bit too dark to me, so I switched to ACES REC709 (yes I did).



Now I think I found a good "in between".


Note: still here renderers.current.options_rgbcolorspace = 2 or 1 doesn't change anything to me. I can switch from one to another and make a new render: not a single change (?).

[DanSHP]

How long are we off a build with full aces support?

Also as things stand just so I have a full understanding how to test, using OCIO maps.

After switching colour spaces and setting OCIO up in VFB. The OCIO maps should be setup like this...

HDRI: In = Utility – linear – sRGB. Out = AcesCG
TextureDiffuseBitmaps: In = Utility – sRGB – texture. Out = AcesCG
Data maps (normal, gloss, Displace etc): In = Raw. Out = AcesCG

Also therefore i would assume we could only usb Srgb display in the VFB OCIO section? Not Rec709/Rec2020 for example, as we have set our texture map OCIO inputs to read our textures/hdri's etc as srgb initially. Or does it not matter?

I'm fairly new to colour managment in general but I've done quite a bit if research months gone by. I'm no 100% confident on this so happy for more knowledgeable to lead the way.

Cheers

[^Lele^]

I think that's because the colors are more saturated under AcesCG, and so they tend to drown the fainter ones from the bounces, at least in this example.
The lower range of the sRGB primaries allows for more bounced green/red to show through.
You'll notice against gray both the bounced reds and bounced greens are far stronger than under sRGB.

[JulianD]

JulianD we're in agreement.
One thing i should state for completenss's sake, is that in AcesCG one would get benefits well visible under sRGB display, for example in GI (or any other such many-bounce effect, like SSS): here, the demultiplication of intensities, coupled with the hue changes as different surfaces are bounced upon, will benefit from the bigger primaries of the colorspace, resulting in somewhat fuller colors.
The standard is maturing, allright, albeit at somewhat slower pace than ideal, i think.

For now the results I got are OK, I was actually expecting more GI colored bounces on the sides of my spheres to be honest. But it's just a box and a couple of spheres after all so, let's wait for more tests.






@aleksandar.hadzhiev:
Can you tell me more about this parameter please "options_rgbcolorspace=2" ? What does it do on lights and GI?
I rendered my cornwell box with rgbcolorspace=2 and rgbcolorspace=1 and saw no difference. Is it only working with textures? (All my colors are vraycolor map)

Also do you know when the new VFB (with full aces workflow) will launch?
Thank you

[hermit.crab]

Does anyone have more information regarding the "from basemap file name" part of the VrayOCIO map ?
from basemap file name – When this option is enabled, the texture will try to determine the correct in/out color spaces based on the file name from the base texture (assuming it is a Bitmap or VRayHDRI texture).

I tried many keywords (I even name my texture simply "sRGB.jpg") but it always puts "aces" in the "in" slot. There is no info on the manual.. What are the keywords for "Utility - Linear - sRGB" and "Utility - sRGB - Texture" please?
Thank you !

The keywords are taken from the loaded configuration - i.e. if you've loaded the aces_1.0.3 configuration file, the sought after names should be "lin_srgb" and "rgb_texture" (i.e. "image_lin_srgb.exr"). You can see all the color space names in the dropdown menu of in/out colorspace parameters.
It may be useful to know that we are working on a better way of approaching the ACEScg workflow without the use of OCIO textures - more detail on the matter in this thread: https://forums.chaosgroup.com/forum/...10#post1055410
Note that the approach is not final, it will be simplified in future V-Ray builds and it will have its own UI.

[^Lele^]

JulianD we're in agreement.
One thing i should state for completenss's sake, is that in AcesCG one would get benefits well visible under sRGB display, for example in GI (or any other such many-bounce effect, like SSS): here, the demultiplication of intensities, coupled with the hue changes as different surfaces are bounced upon, will benefit from the bigger primaries of the colorspace, resulting in somewhat fuller colors.
The standard is maturing, allright, albeit at somewhat slower pace than ideal, i think.

[JulianD]

I had to make a whole movie viewing my renders in Log space on an sRGB monitor, so things can definitely be done head over heels, and come out fine.
I'd still vote for a *linear*, scene referred pipeline, and would let compers do their stuff later, in the right environment.
If i have to double a light's intensity, it'd better double, exactly, in my renders, or madness would ensue.

you'll notice i am not alone thinking this:
https://www.lightillusion.com/aces_overview.html
"Scene Referred is also often in Linear Light, which while suitable for computer graphic rendering, is not suitable for grading workflows."

I totally agree with that and I never meant the opposite, don't get me wrong. What I said was: once you know your display target you don't need to check another one because it will never fit your final image. Now, jumping from sRGB to Rec709 won't get you far from your final result, so yes you could "cheat" that way if it helps.


Does anyone have more information regarding the "from basemap file name" part of the VrayOCIO map ?
from basemap file name – When this option is enabled, the texture will try to determine the correct in/out color spaces based on the file name from the base texture (assuming it is a Bitmap or VRayHDRI texture).

I tried many keywords (I even name my texture simply "sRGB.jpg") but it always puts "aces" in the "in" slot. There is no info on the manual.. What are the keywords for "Utility - Linear - sRGB" and "Utility - sRGB - Texture" please?
Thank you !

[^Lele^]

I disagree. I use a sRGB monitor, why would I jump to another colorspace if I'm watching my render on my screen at the end? I can sometimes have a look at DCI-P3 to see how it would look like in a cinema, but it can't be the reference for my display target.

I had to make a whole movie viewing my renders in Log space on an sRGB monitor, so things can definitely be done head over heels, and come out fine.
I'd still vote for a *linear*, scene referred pipeline, and would let compers do their stuff later, in the right environment.
If i have to double a light's intensity, it'd better double, exactly, in my renders, or madness would ensue.

you'll notice i am not alone thinking this:
https://www.lightillusion.com/aces_overview.html
"Scene Referred is also often in Linear Light, which while suitable for computer graphic rendering, is not suitable for grading workflows."

[stevejjd]

I would love to see a full guide on setting up a proper color pipeline. Maybe this could be possible when the new VFB comes out with full support of ACEScg.

[muoto]

When i tried out Aces, i used the rec2020, which made the whole image more softer and got nice colours.

But the workflow is this not so easy to set up, and i finally ended using a 3Dlut that kind of mimicks the same curves corrections, which works kind of.

And i can save directly to jpg from the vfb

[psanitra]

Sure, you can disagree, but it`s not going to change the fact that with sRGB view transform you going to get blacks crushed. And you will need to find a way how to check your dark areas in renders/shaders/setup when working in max. You can do it with VFB rising exposure, with curves, level or whatever, but me personally find it easier to flick to rec709 for few seconds when i need to check dark areas.
It`s not a big deal, i`m sure you know it`s just view transform, it`s not baked into actual data/exr, you still work in same setup/lightning conditions. I use ACES workflow for close to 2 years now, in can be a pain sometimes, but don`t fight it, adapt or dont use it

[JulianD]

- if you load jpg and set VrayHDRI map loader to sRGB as you did, then you already linearized the image(from 2.2 to 1) and should set the Aces input tranform to Utility - Linear sRGB
- if you load jpg and set VrayHDRI map loader to None, then you should use Utility - sRGB Texture.

Yes, that's what I understood once I read the manual so I decided to make a second experiment.

Nota: "colorspace" in vrayhdri should definitely be renamed "Transfer Functions", because that's what it does: OETF / EOTF / none Transfer Function.





Now my highlights seem blown up, and I'm stuck here, I'm out of ideas. Everything seems well set up at this point.

If you use ACES - sRGB as view transform, it`s normal to get a bit more contrastly image, view transform is "S" shaped curve, it will crush blacks and compress highlights. If the crush is too much for you, you can use rec709 as view transform, that gives more room to the shadows..

I disagree. I use a sRGB monitor, why would I jump to another colorspace if I'm watching my render on my screen at the end? I can sometimes have a look at DCI-P3 to see how it would look like in a cinema, but it can't be the reference for my display target.

[joconnell]

Apologies for jumping in with both feet, I'm on 3.6 here and we have display device as our monitor profiles and then view transform for the grade on our footage.

[psanitra]

- if you load jpg and set VrayHDRI map loader to sRGB as you did, then you already linearized the image(from 2.2 to 1) and should set the Aces input tranform to Utility - Linear sRGB
- if you load jpg and set VrayHDRI map loader to None, then you should use Utility - sRGB Texture.

If you use ACES - sRGB as view transform, it`s normal to get a bit more contrastly image, view transform is "S" shaped curve, it will crush blacks and compress highlights. If the crush is too much for you, you can use rec709 as view transform, that gives more room to the shadows..