Jonathan Mack

The rop has a parameter for 'files to save' that lets you control exactly which layers are saved. It probably doesn't save any cooking time, but will save I/O time and prevent file updates to files you don't want to change.

Is this for Karma? Does it need to be a mtlx material and not a karma material?
When using a karma material the karma aov node can be used.
MaterialX doesn't natively support AOVs which is why the dot workaround is needed.

AFAIK, that's not a feature of USD