Using a Feature Algebra for Reasoning About Geometric Feature Interactions

Abstract

( AD generated objects can be defined in terms of the complete geometry of the part. In automated process planning, the geometry is the same, but the meaning associated with this geometric structure is different, and dictates a change in the description. Various solutions have been proposed to solve this incompatibility, including automated feature extraction, design by features, and human-supervised feature extraction. An important problem to be addressed here is handling feature interactions. Due to geometric interactions among the machinable features, there may be several equally valid feature interpret ations for the same part. This paper describes an automatic way of computing alternate feature interpretations, using an algebra of feature interactions. This will enable automated process planning systems to decide whether various interpretations of a part as a collection of machinable features are feasible for manufacturing, and among the feasible ones, which is the most appropriate one for manufacturing. Alternate feature interpretations are computed by performing operations in the algebra. Furthermore, various provable properties oi the feature algebra aid in resolving a majority of the feat ure interactions without even applying the operations in the algebra, thereby improving the efficiency of the algebraic approach. 1