Matt Tillman

As @robp_sidefx mentioned; the matte collection works on geometry prims only. So you need to set the expansion rule to "expand primitives" to correctly apply matting to prims under the specified parent prim.

There are some other tricky things too, like with the prune collection you can't exclude a child from a specified parent like you can with the prune LOP.

I have a tutorial covering it in depth but haven't had the time to finish editing it. Hopefully I'll get it out soon.

You could try adding the usdvolumesavepath attribute in SOPs to specify the output path for the VDBs.

https://www.sidefx.com/docs/houdini/solaris/sop_import.html#vols [www.sidefx.com]

Yeah that's odd. Looks a bit like what the resample was doing. The fractional frames had the pivots going all over the place.

Weird that it worked on my end.
Did the Cache LOP set to 0.25 work? (In the scene file I sent).