A "master part" is any constrained part that is designed to be used as a template for generating variations. For this application, the constraint information is just as important as the geometry of the part, and should be considered an integral part of the part. In order for a master part to be used successfully, the constraints must be robust enough to correctly generate the full range of required variations, and they should be set up to be accessible and easy to use, especially if the master is to be used by several people over an extended period of time.

To achieve these goals, the following procedure should be followed to prepare a master part: