USDPreviewSurface Roughness Rendering in Maya

V-Ray V-Ray for Maya Issues
1

USDPreviewSurface roughness properly is resorting to fall back value when using a texture input.

Steps to Reproduce (images below):

New Maya Scene

Create 3 Spheres

Assign Each Sphere a USDPreviewSurface

Set Metallic Value to 1 for each Material

Assign File textures with varying darknesses for roughness (doesn’t seem to matter if what channel is used), set color mode to Raw

Group Spheres Under Transform Node

Export as USD with materials set to USDPreviewSurface

New Maya Scene

Create Stage from File

Create VRAY Dome Light

Observe correct roughness in the viewport

Render & Observe that all spheres have the same roughness

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Using Maya 2024.1, Maya USD 0.25, VRAY Nightly Version 61002 from Nov 8 2023

Please help! I urgently need a solution to deliver a product.

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image.png2246×1402 364 KB

Created Textureset With Only Difference Being Roughness (0,0.5,1)
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image.png4005×1216 470 KB

Assigned files to USDPreviewSurface as normal
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image.png775×1338 25.6 KB
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​Exported USD File
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image.jpg3220×1093 940 KB

Assigned USD Reference in Working File
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image.jpg3052×1258 1.03 MB
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​Error Occurs with CPU & GPU Renderers

2

Unbelievable, despite trying to solve this for days, hours after I post this, I finally found the issue. This is still definitely an issue since the viewport shows these properties properly assigned and the renderer is the one having the issue, also what was causing the issue was not having the same effect in Arnold.

The issue tripping up VRAY was the “Mask Map” which has Metallic in the Red Channel and Occlusion in the Green (normally used in Unity, the reason I was trying this was to prevent having to export a different texture set for Unity). When this map is removed the roughness was read correctly. I can only assume that VRAY is having issues resolving a map with two separate outputs???

Please fix this, I have a lot of content already set up like this, thinking VRAY would interpret USDPreviewSurface the same way as Arnold (was having to use it temporarily as our purchasing department sucks).

3

According to this page, USD 0.25 is not yet supported. Could you try reverting back to 0.24 and see if the issue occurs? I tested with an older version 0.16.0 and had no issues with channel-packed maps.

4

USD 0.25 It is supported on the Maya nightlies, so give it a shot and see if it works

5

This was using VRAY Nightly Version 61002 from Nov 8 2023. There’s a new version in the nightlies, but it has no relevant changes.

6

Tested with Maya 2024, stable nightly 61002, USD 0.25 and still no issues. Check the attached scene. Do attach yours so we can troubleshoot.
1194852.7z (5.84 MB)

7

It appears the issue has been fixed. Looking at the release notes VMAYA-12374 might have been the root of the issue.

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