A feature-based CAD representation enabling case-based planning across multiple manufacturing applications

Intelligent manufacturing systems require an interface between computer aided design (CAD) and computer aided manufacturing (CAM) to permit reasoning about how the designed part will be recognized, manufactured, manipulated, and inspected. Two significant obstacles to achieving an efficient CAD/CAM interface are addressed: 1) low level geometric CAD representations, and 2) employment of CAD data for planning manufacturing applications. These obstacles typically lead to narrowly focused applications that use data formats specific to the particular implementation. In this paper, the overall part geometry is described in terms of features and interactions of those features. The data representation of the part geometry is implemented as a collection of class hierarchies (inheritance trees). Different levels of abstraction in the part geometry are defined in separate class hierarchies. Semantic relationships between these class hierarchies relate the different abstractions of part geometry. These relationships define a context for lower level geometry with respect to more abstract geometric definitions