Hello.

Back in H18.5, LOP Import SOP appears to automatically import primvars into SOP as primitive attributes. However, H19 doesn't seem to behave in similar fashion. Are there now different mechanisms to import primvars as primitive attributes?

Thanks in advance!

The LOP Import SOP doesn't import primvars - that happens when unpacking the packed USD prims.

I think in 18.5 there was an odd behaviour where when a packed USD prim was created, if it had a non-boundable type (like Xform) then its primvars were imported as attributes on the packed USD prim. This was a leftover from the original Pixar integration, and didn't support all attribute types and ignored the usual import options like the primvar filter. And, of course, this only happened for certain prim types and made unpacking / transferring those attributes complicated.

This was replaced in 19.0 by an option on Unpack USD to transfer inherited primvars when unpacking.

Also, if you do need to access primvars before unpacking, the usd_* vex functions can now be used from SOPs to read data from the LOP stage.

Hi Cameron, much appreciated your input on this. I was in the process of putting together a sample issue to support@ for guidance. I'll give this another try. I have previously thought usd_* VEX functions were strictly for Solaris context.

Thanks!