On families of objects and their semantics

An approach is presented to define a family of objects in parametric modelling. It avoids an inherent problem of boundary re-evaluation in current parametric modelling systems. Even more important, it offers an effective way to define the properties, or semantics of a family of objects. A family of objects is defined by a prototype feature model, including several types of constraints to precisely specify its semantics. A family membership test is used to check whether an instance corresponding to a particular set of parameter values belongs to a family. The underlying geometric representation is a non-manifold cellular model.