I would not say that it is virtually impossible to reuse geometry amoung different Solid Modeling packages. Solid Edge & Unigraphics claim that they can share model data, and who knows what will happen with EDS's purchase of SDRC & UGS. Also, PTC claims that it can do everything! It all comes down to the capabilites of the modeling kernel. My experiences have shown me that CoCreate's SolidDesigner with their ASIC Kernel is the best at being able to modify geometry from CAD packages, but is that what we really want to do?
501 Cahoon Road
Bay Village, Ohio 44140