sRGB textures to ACEScg?

[Morbid Angel]

AcesCg is a display transform nothing more. We would treat textures as you would with any other display transform. With that said, for us we work in full exr pipeline which means all of our textures are exported as exrs. This means when loaded they are not treated in by any color transforms (so raw loading) and all things work fine. I'd recommend trying that workflow.
In some cases when painting textures out of substance we have to set the substance display as acescg as well to ensure colors are correct as some colors may be affected if you are looking to get accurate color match. Something to keep in mind.

[piotrus3333]

AcesCg is a display transform nothing more. We would treat textures as you would with any other display transform. With that said, for us we work in full exr pipeline which means all of our textures are exported as exrs. This means when loaded they are not treated in by any color transforms (so raw loading) and all things work fine. I'd recommend trying that workflow.
In some cases when painting textures out of substance we have to set the substance display as acescg as well to ensure colors are correct as some colors may be affected if you are looking to get accurate color match. Something to keep in mind.

do you mean loading exr colour related textures (like diffuse etc) with RGB primaries: Raw ?

[Morbid Angel]

Yes, if you simply export all your textures out as exrs the diffuse, roughness etc then vray will properly treat them out of the box. It's not even vray that's doing the color conversion. Maya file node automatically sets the color, but for example it does not know which texture is going to be used in which slot of the shader. So for rgb color like diffuse you need it to be in sRgb color space, while other textures need to be in raw even if they are jpg, png or other 8 bit formats.
The bad thing about Aces is that it physically requires to convert all textures to aces compliant format, that's the reason acescg was created so you don't have to set every texture color space. With exr tho you solve the issue of color and utility texture that's suppose to be mapped into channels like roughness, normal map etc.

[piotrus3333]

Maya file node automatically sets the color based on what? filename? exr metadata?
or the rendering space in VRay is always sRGB?

[Morbid Angel]

In maya there is a color management section in preferences where the rules are applied / defined by maya it self. It is in those rules where it defines which formats get which color space. Vray simply applies acescg to the frame buffer as a view transform, it gets that value from the color space in prefs as well. That's how the whole wheel turns.

[piotrus3333]

thanks for details.
pretty much the same case in max these days: