CompuServe Messages

Sounds to me like your face normals are turned inward instead of pointing outward. A quick experiment to prove this theory would be to assign a 2-sided material and render. If the sides show up then you will have to either live with the 2-sided material or flip all those faces so that their normals are pointing outward. Face normal abnormalities are inherent in working with Autocad, although I have never had this problem with primative objects like a cylinder. Lee