USD Preview Surface consistency

Hello everyone,
I know this not a channel for platform support but I don’t exactly know wich program in the pipline is causing the problem and it’s also about usd implementation so I ask it here.

I discovered a really weird bug: When I texture my modell (usd exported from houdini) in mari I mainly use the usdpreview surface and it works great. If I now export the LookFile with shaderassignments (through usdexport manager) and reference that over the geo I get a beauiful preview and everything is as expected but only in Storm. Every other delegate picks up no shader information at all. (usdview from Nvidea Omniverse renders the exported assembly from Houdini perfect)
If I then use the editmaterial node in solaris as a reference to rebuild the usdpreview surface again in another material library in wich I assign the surface to everything. As soon as I do that nothing work everything turns black even in storm. The really wired thing is when I delete this material library everything works GL (roughness is off), Karma, Storm.


Normal LookFile workflow:

Own USDpreviewShader rebuild and assignment:

Own USDpreviewShader rebuild and assignment but deleted again:

I tried importing only the geo and building my own preview surface identical to the one from mari but it only renders correct (roughness is off again) in GL. Karma and Storm are picking up some kind of average of the color.

I suspect it’s mostly a houdini problem I’m using 19.5.682 by the way but it’s really wired. Does houdini not yet support look files because I don’t think you can export such either. Interesting that storm supports them though even better than the normal previewsurface in houdini.

Another problem I realised is that the bump iformation which works in the mari viewport doesn’t cary through to any delegate not even usdview (in houdini there isn’t even a bump input). So does mari have a modified usdpreviewsurface? Because I thought this sourface is supposed to be a standard?

Well that was a lot… probably I’m just pointing out a bug on wich the super smart guys from sidefx are already working on but as this forum is working on setting standard I thought this might interest some of you.
Or I’m just making something wrong in this case I would be more then happy to recieve tips on how to get a consistent previewsurface across DCC and delegates!


Can you share any of the actual USD files here? I have no idea how Mari outputs USD, so it’s impossible to guess why Houdini might be having problems with it, but I’d loved to get this figured out…