Import conversion to Maya native shaders leaves all materials as PreviewSurface

[aherr1]

I'm attempting to use the functionality described in pull request #707. I'm wondering if I'm missing a step. Currently, my process is exporting a large textured USD file from Unity, selecting the import menu in Maya, selecting Files of Type: USD Import, and under File Type Specific Options, selecting Lambert (or another shader). No matter which shader is selected for the conversion, the materials all remain as PreviewSurface. Even unchecking the materials checkbox does not affect anything, and materials are all still imported as PreviewSurface.

Would anyone familiar with the import conversion process be able to explain the steps needed to convert from USD preview surface to Lambert? Thanks!

Edit: I ended up successfully importing a USD file with a conversion to Lambert by using a different import type "pxrUsdImport" through a script command.

file -import -type "pxrUsdImport" -gr -ignoreVersion -ra true -rdn -mergeNamespacesOnClash true -namespace ":" -options ";shadingMode=[[useRegistry,UsdPreviewSurface]];preferredMaterial=lambert;readAnimData=0;useAsAnimationCache=0;assemblyRep=Collapsed;startTime=0;endTime=0;useCustomFrameRange=0;importInstances=1" -pr -loadReferenceDepth "all" -importTimeRange "combine" "C:/usd_export_test/test.usd";

I'm assuming that means the preferred material functionality is only available on the import type "pxrUsdImport". However, in the import menu for the pxrUsdImport file type, there is no dropdown to select a preferred material. Is this functionality available in a menu anywhere, or only through a script command?

Related Issue: I'm also not seeing textures displayed properly - all textures show up as bright white, despite the texture image being correctly loaded and linked to the Color attribute.

[JGamache-autodesk]

Hi! Could you paste the command that is output to the script editor when the import is wrong using the UI? That would help find out what happened.
Thanks!
Jerry.

[santosd]

2021-01-12.11-23-36.mp4

Hello @aherr1, I did a test on my end in Maya 2020.4 and was able to get the expected results. As you can see from my video above, when I convert to Lambert on import the transparency is not translated. At this point this is expected as there are certain attributes that don't translate well from usd preview surface to other material types.

In regards to the textures not displaying properly, do you have any specific settings for Color Correction in the viewport? Would you be able to provide a file and\or possibly a video showing the issue that you are seeing on your end?

Thank you.

David Santos