Bugs for exporting material as UsdPreviewSurface


I tried to export some assets to USD, but it seems that the export UsdPreviewSurface material is not valid. For example:

here is an exported texture shader, which is linked to diffuseColor of UsdPreviewSurface inputs

def Shader “diffuseColorTex”
uniform token info:id = “UsdUVTexture”
float4 inputs:fallback = (0, 0, 0, 1)
asset inputs:file = @a06_parrotPreviewSurface/AM83_006_color_02.jpg@
color3f outputs:rgb

  1. the texture path always has extra “PreviewSurface”, i.e. the correct path should be “a06_parrot/AM83_006_color_02.jpg”

  2. some times, this path refers to other image file

  3. it seems that only diffuseColor inputs in UsdPreviewSurface is supported for texture, right?

This is actually expected behavior, the usdpreview surface has “PreviewSurface” appended in order it tell it apart from the MDL render context.

For the ,mapping itself, we are improving the mapping to usd preview surface next release with even more materials supported.

Hi,thanks for your reply!

Regarding the suffix of “PreviewSurface”, the thing is, it is strange that I can NOT find the corresponding folder (“a06_parrotPreviewSurface”) in the exported path, i.e. I can only find “a06_parrot” folder.

@wangchiemail! I asked the development team to help answer your question.

What is your Plugin version? It could be a bug in old version.

Hi, I just upgrade to 102.1.35, and I use Max2019.

This should not happen with this version. Do you still have the problem? Can you tell me what is in your scene? What are your exporting options in the exporter dialog?

Hi,I think the problem remains. Basically, this happens to every scene, so maybe it is not so relevant to scene.
Here are some screenshots.

The followings are the reported result, and “PreviewSurface” folder is missing…

I see. This is a bug with option Split Into Multiple Files. You can turn it off and try again.

Hi, if I turn it off, it still happens.


I forget to mention this window pops up after export.

This is really strange. Can you upload your sample for me to try?

Here are the exported usd files and original max scene.

exported_usd.rar (3.8 MB)
max_scene.rar (4.0 MB)

BTW, the scene is from evermotion online shop.


I can now reproduce the bug. It seems that it uses VRay material. If you use physical material with simple bitmap texture, it should work fine.
Sorry for the trouble. We will improve the codes to make it work right with VRay material.
As a workaround, you have to fake the folder and the picture with the current version. Or, you have to change the file path to the folder which has the texture in Usda.

Thanks for your help! Looking forward to the next release. :-)