Colorspace name defined in ocio config cannot be used in file node

[hiraku_fukuda]

Hi there,

Maya's file node has an attribute called colorSpace, but it seems that vray only works with a specific colorspace name.
Are there any plans to support colorspace names defined in ocio config in the future?

Valid colorspace names that I have confirmed (there may be others)
- ACEScg
- sRGB
- Raw
- scene-linear Rec 709/sRGB

Maya Version: 2023.3
V-Ray Version: 6.10.01

[hermit.crab]

I don't think that's V-Ray related. If I understood correctly, you have a custom transform and you wish for it to appear in the Color Space menu? I think this should be somehow done in the OCIO config itself.

[hiraku_fukuda]

Thank you for your reply.

It seems like I didn't explain enough, so I'll give you an example.

1. In maya, set the following in [OCIO Config Path] of Color Management
   • <MAYA_RESOURCES>/OCIO-configs/Maya2022-default/config.ocio
   • Rendering Space is "ACEScg"
2. Select the ap0 texture in the file node
   • The texture I used is this
   • https://github.com/colour-science/co...hecker2014.exr
3. Set "ACES2065-1" to the colorSpace of the file node
4. Render

But, vray does not convert colors correctly.
Normally it should be converted to ap0(ACES2065-1) -> ap1(ACEScg)

The following log appeared
// Warning: V-Ray : Unrecognized texture color space ACES2065-1, texture may render wrong
// Warning: line 1: V-Ray : Failed to init Texture RGB Color Space conversion from ACES2065-1 to acescg

Colors are converted correctly in Maya's viewport and Arnold.

Thank you.

[hermit.crab]

Understood. The color space options in the File node support only the most used conversions (it uses fast on-the-fly ones; ap0 not included). However, you can use VRay Tex OCIO, in which you load the same .config file.

Just a note: ACES2065-1 is not supported as an internal rendering space, so even if textures in this space, VRaySky, temperature of lights, etc. won't be.

[hiraku_fukuda]

Thank you.

I understand that the only way to do this is to use VRayTexOCIO, but it is quite cumbersome when building a workflow.
If possible, I would be happy if it would also support colorspace names in ocio config.
Are there any such a plan on the roadmap?

[hiraku_fukuda]

HI,

Could you give any updates on this?

Thanks

[Muhammed_Hamed]

Hey hiraku_fukuda

Could you please tell us more information about your workflow, are you trying to use AP0 primaries as your rendering space? why?
Do you have textures or assets in this colorspace, you wish to convert to sRGB or ACEScg color spaces?

This will help us give priority to your request, it should be possible to add more conversions to the file node in Maya

Best,
Muhammed

[hiraku_fukuda]

Thank you for your reply.

ap0 was an example for easy explanation.

This time, the request is "I want the file node to support the colorspace of ocio config'', but there are several reasons.

1. When I want to use "Gamma 2.2 AP1 - Texture" exported from substance painter, it cannot be read correctly with the current vray.
   Also, it is unproductive to have to add conversion each time such a unique colorspace.
   If you support colorspace of ocio config, this will no longer be necessary.
2. By using VrayOCIOTex, you can use any colorspace, but there is a problem that the colors change when you change the working colorspace.
   Also, I don't want to increase the number of nodes.
3. In the first place, it is troublesome to have to verify whether the colorspace of the file node is compatible.

Thank you.

[Muhammed_Hamed]

[*]When I want to use "Gamma 2.2 AP1 - Texture" exported from substance painter, it cannot be read correctly with the current vray.
Also, it is unproductive to have to add conversion each time such a unique colorspace.

If AP1 is your rendering color space, it is easy to use a Gamma 2.2 AP1 Texture. All you need is a transfer function, you can load the texture as raw, and apply a gamma after, in the file node

About having a unique colorspace, we support sRGB and ACEScg as working spaces in V-Ray and V-Ray GPU. These are the standard color spaces used in the industry at the moment
That being said I see the potential of having other custom color spaces based on your OCIO config, for experimenting
I will add a ticket for your request

1. By using VrayOCIOTex, you can use any colorspace, but there is a problem that the colors change when you change the working colorspace.
   Also, I don't want to increase the number of nodes.

Depending on the conversion you are using, it is expected that you get difference results with different working spaces
This works without issues on my side, if there is a specific conversion you suspect is wrong let me know

Best,
Muhammed

[hiraku_fukuda]

Sorry for my late reply.

I'm sure it can be done using the method you described.
However, I think the color control is a bit complicated.
I think it would be simpler and better to be able to control it with ocio's colorspace, but I found out that there is no such plan, so it's okay for now.

Thank you for your reply.