Jonathan Mack

I don't think the cross format is supported. Convert to a cube map or a latlong.

Jonathan de Blok
Is it me or is replacing a branch from USD not a thing? Got incoming geo with cheapo materials, got a nice material lib setup in LOPs with identical path and names etc.. been trying for an hour to replace the materials on the incomming geo. Merging/layering/etc it over somewhat works for CPU Karma, not for GPU. Also the enable texture flags are ignored by the conversion, I'll add it to the pile of bug reports I still have to make on Solaris Karma.

that's not how the layering works, you wouldn't attempt to combine a material with an overlay of a different one, that would just end up with a corrupt mess. You would have to replace the material, which isn't a thing in USD. There is no replace only combine.

the proper way to layer is to create a new material with a non-conflicting name, and in the layer also change the material assignment to this new material. This way the layering will combine like for like. An empty prim containing an assignment opinion will overwrite the existing assignment in the lower priority layer. The way to directly layer the material itself is with a topologically consistent change, such as changing a texture path(s) or shader parameter(s).

You could use a node color theme. I forget how to edit the theme in houdini, but they're just json (or some other markup) files that can be edited with a text editor manually.

Edit:
to add a node color to the current theme, ctrl-drag a color from the palette to the node to be added to the theme. This will color all future and current nodes of this type as long as the theme is active. The network editor properties dialog allows selecting the theme and duplicating and existing one.