MaterialX / glTF / USD material interop

Community USD
1

Continuing the discussion from SIGGRAPH 2023, Open Source Days 2023, etc. Sessions Round-Up
which mentions GLTF, MaterialX, and USD in the presentations:

I’m curious what the thoughts are on maintaining this “triplet” in terms of materials, as there can be any or all of these bidirectional transfers occurring depending on workflow:

  1. USD ↔ MaterialX
  2. USD ↔ glTF
  3. MaterialX ↔ glTF

I’d assume you’d want each to be as lossless as possible and kept in sync as much as possible.

Thanks,
Bernard

2

USD can encode more than MaterialX can encode more than glTF. So if there’s a glTF MaterialX file, you could losslessly

gltF → MaterialX → USD

There’s talk of adopting MaterialX into glTF but until such a thing happens, the reverse direction, USD → MaterialX → glTF is strictly a narrowing.