I’ve been experimenting with USD and MaterialX data between Maya and Unreal and have encountered an issue regarding the USD Stage Editor. When I load a USD file which uses a MaterialX shader containing UDIMs (nameoftexture.1001.exr) it wont load and display the texture in the level editor. Even if the Render Context is set to Mtl and Material Purpose to All, it only displays the USD geometry without its shading and texture. If I edit both my MaterialX file and texture with no UDIM naming convention then the texture will load and display correctly. Does anyone know if UDIMs are natively supported within the USD Stage Editor? Could it be a USD specific design or simply a limitation within Unreal’s USD Stage Editor as of 5.5? I’ve already enabled virtual texture streaming for my Unreal project too, if there is any requirements to get the UDIM textures to work for the USD Stage Editor.
The main reason I ask is because I’d prefer to not assign multiple materialX shaders to various USD assets such as terrain/landscape mesh tiles if they are also using UDIM UVs and texture naming convention too. Anyone else testing out a similar workflow?
I can confirm as of UE 5.5.3 that textures can be previewed/displayed within the USD Stage Editor if they’re NOT using UDIM naming convention. I’ve only tested this on one mesh, but it’s still an issue if many meshes rely on a shared MaterialX shader that reads UDIM named textures.
Using the USD Stage Editor’s Import option to convert the USD data to UAssets ends up requiring to manually import an EXR file into Unreal’s Content Browser. Dragging and dropping one EXR file seems to source all the textures that use the UDIM naming convention. When assigning the texture to the generated Uasset material, not all the meshes have the textures mapped correctly even if the UVs were setup in another program such as Maya.
I don’t know if fixing the USD Stage Editor to be able to read UDIM textures from a MaterialX material could resolve the mapped texture issues when importing/converting the USD data to UAsset format.
I’ve added a screenshot below showing a texture without the UDIM naming convention, which causes all the other USD geometry to read the same texture while using the same MaterialX material.
