@greenskp said:
Someone knows of one workflow to it doesn't happen?
I believe if you triangulate, you can avoid writing a material for each face. See info in this post:
http://sketchucation.com/forums/viewtopic.php?f=323%26amp;t=44501%26amp;start=120#p513778
ThruPaint is magic! Definitely the way to go if you can get what you need that way.