FSMT: a feature solid-modelling tool for feature-based design and manufacture

Abstract

The paper presents an engineering environment called the Feature Solid Modelling Tool (FSMT). In contrast to the common approach of simply attaching manufacturing information to existing geometric models, the feature definition in the FSMT has been greatly augmented. A geometry is always associated with the knowledge of applying it. The knowledge represents the theory and methodology of design and manufacturing, and a cad/cam integration strategy. Generalized sweeping has been developed as a unified method for defining various features. Through the development of a dual representation schema of a CSG index and a B-rep index, attributes such as tolerance and roughness can be conveniently assigned to individual surfaces through the CSG model or the B-rep model. The CSG model and the B-rep model are easily accessible, and the underlying consistency and integrity are guaranteed. The feature definition also provides a sound mechanism for mapping into applications such as FEM-mesh generation, process planning and NC programming. As a result, feature information is directly available to downstream activities, and feature extraction or recognition is no longer needed. The integration of cad and cam is accomplished to a greater degree. A prototype system has been developed.