N-Rep: A Neutral Feature Representation to Support Feature Mapping and Data Exchange Across Applications

The proliferation of different feature based systems has made feature data exchange an important issue. Unlike geometry data exchange, where different representations use the same fundamental concepts; the most popular being B-Rep and CSG [Shah et al. 88], different feature representation schemes use different concepts to represent features corresponding to the application and domain. Therefore, feature data transfer between applications not only involves transfer of instance data but also transformation of feature concepts. This paper presents N-Rep, an application independent declarative language, for feature definition that includes topology, topological relationships, geometry, geometric relationships, parameters and parametric relationships. N-Rep has been designed to serve three roles, viz., (a) to generate feature recognition algorithms for recognizing features from geometry, (b) to generate feature producing procedures to be used in design by feature approaches, and (c) to serve as a neutral feature data exchange medium between representations.