thanks for the info. That works. Unfortunately It seems that I cannot rename materials without creating new ones. I am using poly.SetMaterialName(newmatname) but this method creates a new material instead of renaming the material. I tried material.Name(newmatname) and that did not have any effect. Maybe if I use SetMaterialName() and copy the material properties to the new material but that is rather cumbersome way of doing it. FlyerX