Add Mask AOVS – 3delight

# select all geo that you want to have a mask and run the script – this will create a 3delight mask aov for each piece.

import pymel.core as pm
selection = pm.ls(sl = True)
for maskobject in selection:
    pm.createNode('3DelightMaskSet',n='Mask_' + maskobject)
    cmds.sets( str(maskobject), add='Mask_' + maskobject )