I am having issues using pxr.Usd.StagePopulationMask() in HOM, or the same functionality using the configurestage LOP.

After using a population mask using either of the above two methods I am seeing errors applying further edits to the stage.

Is the stage no longer editable once a population mask has been applied?


Hip file attached;

Just a note that you should not use layer muting, stage population masking, or payload loading APIs inside a Python LOP. They may appear to work at first but will cause issues down the road. You should only use the Configure Stage LOP to make these kinds of modifications to a stage. I saw this going horribly awry when I opened your hip file the first time, with the python LOP selected and
displayed. It sets the population mask, but as I move the current/display flag to other LOP nodes, that population mask set in the python LOP has now “infected” every other LOP node, and there is no way to get rid of the population mask other than restarting Houdini (or deleteting all the nodes and then undoing the deletion).

As for the warnings/errors: stage population masking is very low level, very strict, and completely unforgiving. I recommend against using it unless you absolutely must. Visiblity and activation control are generally more forgiving (though deactivated prims can produce similar issues). The warnings/errors are occurring because attempting to create /foo when the population mask doesn't specify /foo as a prim in the mask will fail. Prims outside the population mask are simply not allowed to exist. So even trying to create them is an error because the creation request fails.

mtucker
that population mask set in the python LOP has now “infected” every other LOP node

Yes, this was the behaviour I was seeing, the population mask was persisting to any nodes stage!

mtucker
Visiblity and activation control are generally more forgiving

I will use activation.

Cheers.