These are 3-D modeling programs used in Engineering to design everything from the Airbus to plastic toys.
These models can then be exported to CAM/CAD programs where parts can be machined or molded directly.
They are RAM intensive and most computers cannot handle them.
Thanks for the explanation. Not a a CAM/CAD guy here. I bet not only RAM intensive, has to be disk intensive also for read/write operations. IIRC, CAM/CAD programs store their information in layers?