Nvidia Omniverse - Udim error when converting to USD and MDL in unreal engine (UE)

Hello :)

The company I’m working in is trying to integrate Nvidia Omniverse to our production pipeline and we’ve been experimenting a few things. One problem we’ve faced is with udims. I’m currently using Unreal Engine 4.27 and even though my udim/virtual texture is correctly connected to the material and the material correctly connected to the mesh, when I export them to a USD file, only the 1001 map shows.

Here’s my workflow: I’ve connected my udim maps, importing 3 udim maps (1001, 1002, 1003) into virtual textures (so ultimately, there’s only one virtual texture), and connected the VT to a material in UE. The instanced material is applied to my mesh and I placed the mesh in a level, saved the level, and used the “export level to omniverse” button to export the level into USD. The path I saved is “Omniverse > localhost > Projects” and when I check the exported USD file, the mesh and shaders seem okay but only the 1001 map is connected to the material. I think the problem is with the textures? The textures are automatically imported when I export the level to USD, and when I check the texture maps, they’re not virtual textures and are imported seperately. 1001, 1002, 1003 maps exists seperately so UE doesn’t recognize the textures as udims. I’ve looked at the MDL/OmniPBR shader in UE and it looks like it doesn’t support virtual textures/udims. Is there a solution to this problem?

Thank you in advance.

Hello @1uniusrose! Welcome to the community! We are so happy to hear that you are using Omniverse! I sent your questions over to our development team. We should hear back shortly!

Ah yes, it looks like we support Virtual Texture/UDIM EXPORTING from Unreal, but we don’t properly generate the virtual textures when importing. I reproduced this locally, and I believe the conclusion that in the near term it was too complicated to properly generate virtual textures on import. I have created issue OM-44958 to track this, but at the moment I’m not sure that we’ll get to it very soon.

Oh, I see. So there’s currently no way to use udims/virtual textures in UE using USD and MDL? Udims/Virtual Textures take up a huge part of our company’s workflow so I hope this issue gets resolved soon! Thank you for the fast reply :)