CompuServe Messages

Since flipping face normals is a toggle (the IN face becomes the OUT face, and vice-versa) sounds like you might be selecting a set of both IN and OUT faces and then, by flipping them, simply getting a set of OUT and IN faces. You need to flip only the faces whose normals are pointing in the wrong direction. The Unify command will attempt to do this for you automatically, and works pretty well for most objects. Also, keep in mind that faces are triangular. You should probably turn on Display/Geometry/All Lines and Backface mode to help see what you're dealing with. If you have a number of jobs with complex meshes and need to do a lot of face flipping (such as on importing improperly made DXF files) you might consider getting Disk #7 from the Yost Ipas Boutique. Its Optimize program has a routine that lets you see the face normals as graphic arrows to help with face flipping. – Jack