Before I file en RFE, I though I would ask here what people think.

I noticed the UsdMtlx (MaterialX File Format and Shader Plugins for USD) is not part of the USD installation that comes with Houdni-18.
Would it be useful/complicated for SideFX to include it in a future build? I would certainly like to start playing with the possibilities it provides since our renderer of choice supports exporting mtlx files.

Houdini currently has no support for MtlX, in LOPs or otherwise. Because of this we don't have a MtlX library built/shipped with Houdini, so we can't build/ship the USD MtlX plugin. If you build your own MtlX library, you can then build the USD MtlX plugin against your MtlX library and the USD library that ships with Houdini. But I'd be reluctant to ship the MtlX USD plugin when we don't have any support for authoring MtlX shaders in Houdini, and I'm not aware of any third party renderers available for Houdini that understand MtlX shaders, let alone understand how to consume MtlX shaders saved as USD and sent to a render delegate (though I may be mistaken about that).

So it would be quite a bit of effort on our part, with questionable gain. And for individual customers, there is the option of building the required plugins for yourself, so there is a workaround.

Not to discourage anyone from voicing support for this feature here. If we are wrong about the importance of supporting MtlX, we'd certainly like to know!

Arnold supports MtlX very well now, and if Houdini could reference mtlx files directly in USD, I could pressure SolidAngle to support it!

I'll talk with my build master here to see what we can do. I'll forward your suggestion.

Thanks Mark!

Agree with flord, having been using Arnold with Mtlx in houdini, even though you need to modify a bit in mtoa mtlx file, it still works well, look forward to seeing the progress of this topic.

ID love to see this propperly working becouse i zhould mean propper substance designer support