Cynthia, You would have to see several examples to appreciate how powerful this feature can be; the attached illustration will give you an idea. The cylinder on the right was a mirror copy of the one on the left before having its top surface replaced by the surface quilt above it. There are numerous other amazing tools in the Pro/E set of tools that can allow you to do difficult things easily. Look at Toroidal and Spinal Bends, for example. David