USD Implementation.

[jmanheyman]

I'm not sure if it's possible, but I'm trying to edit your blendshape deformer compunds to work with USD data. I'm not very coding experienced, especially with the USD api, so I'm not sure if the compound's data would hold if the USD files it edits are brought to another DCC and back, for example. My current testing has been trying to figure out how to convert the face attributes assigned from the selection sets to USD attributes or potentially primvars. I think it could be useful, as blendshape implementation seems to be pretty bare bones for USD, from an artist standpoint. I'd ideally like to just make blendshapes in Maya, save them as USD files, and interact with the same blendshape in Unreal or Blender. When USD exported blendshapes are brought into Unreal for example, I'm not able to play with any exposed parameters that would allow me to interact with that data. It's the same in Maya AFTER it becomes USD data. But, with your compound, I'm able to make blendshape edits to a target mesh prim. I haven't tested it yet, but I know the group attributes created from the dl_bifrost_utils script you made don't transfer over to the USD mesh, therefore (in theory), once the USD file that I'm able to deform is exported and brought back in, I'd no longer be able to deform it like before. This matters for future usability only, as if I were doing this the current "fast" way, I'd just use Maya data and FBX. Has anyone looked into this at all, or is it hopeless at this point until Pixar, Autodesk, or Nvidia decide to update the API with more "user-friendly" Blendshape things? I'm not super well versed in the API, Bifrost, and coding in general to get a good grasp on if it's pointless to try and make happen or not.