Color Management with Maya 2022 and Renderman 24

[Anonymous]

I just upgraded to Maya 2022 and my preferred render engine is Renderman (24). Since upgrading, my color management workflow is off. Prior to this I could texture something in Substance painter, assign the textures in Maya and get a render that is very close to what I created in SP. Now, everything is way to dark. I'm thinking it has to do with the ACES color space, but I'm not sure how to resolve this. All non EXR textures are linearized. Any suggestions?

[rogueninjacreative]

I know this question is old, but I was running into the same problem with Maya 2023.1 and RenderMan 24.4 on macOS 11.6.8.

Using a linear workflow, colour values from a texture in sRGB colour space (before being linearized) should be pretty close to the colour you see once the image has been linearized, applied to a model, and rendered in a linear render space (with an sRGB view transform applied, of course). Also, those same colour values should produce the same result when entered into the diffuse colour lobe of a pxr surface in Maya, with "Display Space" as the mixing colour space. This was my expectation and what I thought was the whole point of working with a linear workflow.

The fact that none of this seems to work anymore could be a compatibility issue between Maya's new colour management system and RenderMan. (Or, I'm doing something terribly wrong). I don't believe the software versions I listed above are officially compatible/supported.

Regardless, the only workaround for me was to disable OCIO in RenderMan render preferences and set the Maya OCIO config path to the legacy configuration. Colour values may need to be re-entered into the Diffuse lobes after changing these settings.

1. Go to Render Settings > RenderMan > Features tab and set OpenColorIO configuration to "Off".
2. Go to Maya Preferences > Color Management
1. Make sure colour management is enabled
2. Click on the small arrow next to eh OCIO Config Path field and select "Reset to Legacy" from the pop-up
3. Now ensure Rendering Space is set to "scene-linear Rec 709/sRGB" and View is set to "sRGB gamma".
4. Also check that the EXR input colour space rule is set to "Raw"
3. Update all diffuse colour values in PxrSurface nodes.
1. Use mixing colour space "Display Space" and enter the RGB values from any sRGB images before they are linearized and used as textures.

With this fix my linear textures looked correct in an sRGB view transform and colours matched between diffuse color and textures.

Hope this helps someone.