render in ACES with substance painter textures

[jasonhuang1115]

Hi,

Having a bit of issue getting Substance Painter output textures to render as expected with ACES in Maya. I am using the preview sphere that comes with Substance Painter to export a set of textures using Vray UDIM preset that comes with SP. An ACES LUT is used in Substance Painter just for viewport preview, not affecting output textures AFAIK.

Questions 1: should I convert the color maps (diffuse and reflection color) from sRGB to ACEScg in Nuke first?

Questions 2: should the Displace Device color transform in VFB OCIO be sRGB, instead of ACES? The dropdown menu doesn't provide any other option other than ACES.

Questions 3: what's the pros and cons of bringing in textures as is and then use VrayOCIO node to do the color space conversion in the Hypershade?

Thanks!

[jasonhuang1115]

I did a few more tests and found a couple of approaches that provide an acceptable match to SP viewport.

First, I use Arnold 5 UDIM (AiStandard) export preset in Substance Painter to output textures as I am able to get better-matched results with them instead of using Vray UDIM preset for the texture export.

Approach A:
SP texture export setting: Arnold 5 UDIM (AiStandard)
no color space conversion in Nuke before plugging maps in Maya
Maya texture file node color space settings:
color texture: utility - sRGB - Texture
data texture: utility - Raw
hdr: utility - Raw

VFB OCIO settings:
Input Colorspace Utililty - Linear - sRGB
Display Device: ACES
View Transform: sRGB

Nuke read node colorspace: Utility - Linear - sRGB

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Approach B
SP texture export setting: Arnold 5 UDIM (AiStandard)

texture color space conversion in Nuke
convert diffuse map from Utililty - sRGB - Texture to ACEcg with sRGB color profile baked through the Write node
convert HDR map from Utility - Linear - sRGB to ACEScg

Maya texture file node color space settings:
color texture: ACEScg
data texture: utility - Raw
hdr: ACEScg

VFB OCIO settings:
Input Colorspace: ACEScg
Display Device: ACES
View Transform: sRGB

Nuke read node colorspace: ACEScg