Feature recognition within a truth maintained process planning system

Abstract A major problem for computer aided process planning (CAPP)is the difference in data representation between the design and planning stages. Computer aided design (CAD) uses a data representation which is suited to solid modelling but is impractical for process planning. A partial solution to the non-unique nature of the set-theoretic solid model is detailed. A method of feature recognition for the set-theoretic solid model, together with its implementation in a process planning system is described. It is essentially a rule-based conversion of the CSG string into a set of manufacturing features. One or more alternative ways of viewing the component in terms of features are produced, and user interaction may be required to determine the best set of features to process plan with.