thanks, If only I could get it to work
-enable skin priorities is checked on all three walls
-I set the channels and corrugated metal to 2 and checked finish component, the sheathing to 4, and the stud to 8 and core component. Horizontal stretch is located at the faces of the stud wall, the opening line is located 1/16 out from the corrugation.
Do you know if it could be the corrugation? I was thinking I've never used curves in a complex profile, but I just remembered I used one to make a table edge once.