There currently seems to be an issue assigning materials via Subset Groups and then exporting a mesh to USDZ.

The ‘familyName’ token should be set to ‘materialBind’ in the USD file, but isn't.

According to the spec: “Material bindings authored on GeomSubsets are honored by renderers only if their familyName is UsdShadeTokens->materialBind”

In Houdini 18.0.361 using the SOP Import node and enabling Subset Groups I am able to assign materials to a GeomSubset and those materials display in the viewport as expected, but once saved using the USD Zip node all materials disappear.

Manually adding the following text fixes the issue.

uniform token familyName = “materialBind”

I have managed to work around the issue by following instructions in this thread, but support for exported Subset Groups would be preferable.

https://www.sidefx.com/forum/topic/71692/ [www.sidefx.com]