Add shading group info to object for export Alembic

add_sg_attr.py

# transformではなくshapeにアトリビュートを持たせないとHoudiniに持っていけないところがミソ
from pymel.core import *
sgs = ls(type='shadingEngine')
for sg in sgs:
    shapes = listConnections(sg.dagSetMembers, s=True, d=False, p=False)
    for sh in shapes:
        shs = sh.getShapes() if objectType(sh, i='transform') else [sh]
        for o in shs:
            attrname = 'sg'
            addAttr(o, ln=attrname, dt='string')
            o.attr(attrname).set(sg.name())
print('# Done')