Default magnification of Emissive Color for UsdPreviewSurface (To reproduce Unlit)

I am reporting on something I noticed while passing contents from Sketchfab to Omniverse.
Since there is no Unlit representation in USD, I think that EmissiveColor is often used when converting from glTF, etc.

Is it possible to change the default Intensity of the EmissiveColor of the UsdPreviewSurface in RTX rendering/Iray rendering?

The EmissiveColor of the USD (UsdPreviewSurface) in Omniverse seemed to be dark unless multiplied by 3000-4000.
So I verified the material UsdPreviewSurface/OmniPBR/OmniSurface’s EmissiveColor.

RTX Real-Time and Pixar Storm compared.

RTX Real-Time

Pixar Storm

I have already figured out that Pixar Storm only looks at UsdPreviewSurface for materials.

In the case of UsdPreviewSurface, it seems that multiplying the EmissiveColor scale by 3000-4000 will give the intended color.
This can be adjusted with inputs:scale in UsdUVTexture, but I have not seen many USD files where this is utilized.

For OmniPBR, this does not seem to be a problem as it can be adjusted with Emissive Intensity.
(Specify 3000-4000 for Emissive Intensity)

For OmniSurface, EmissiveColor is just fine.
It seems to be a requirement that “Emission Mode” be “emission_lx”.

The meaning of “Emission Mode” is taken from the following document.

Operating environment

Omniverse Create 2021.3.8/2022.1.0 (Windows 10)

Operating Procedure

Sample file have been created.
After unzipping, test_EmissiveColor.usda and tile_image.png will be extracted. (15.1 KB)

  1. Launch Omniverse Create 2022.1.0
  2. Open test_EmissiveColor.usda

Thank you @ft-lab! We appreciate your help in finding these bugs! I have informed the development team and I will let you know when I have more information to share!

(An internal development ticket was created for this post: OM-48273: Default magnification of Emissive Color for UsdPreviewSurface (To reproduce Unlit))

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