Application of Constraint Propagation in Part Family Modelling

Summary The paper describes the use of an incremental constraint propagation technique for feature-based modelling of group technological part families. The constraint representation is based on a multigraph where nodes represent constrained variables and multiarcs the various constraints. Through the variables, the multigraph is integrated with a LISP frame based feature representation. A constraint specification language for representing constraint types in feature and part family definitions is also discussed. The system has been implemented in the context of the EXTDesign feature based modelling system developed at the Helsinki University of Technology. The work is considered a contribution to computer-aided design methodology.