B-Rep model simplification by automatic fillet/round suppressing for efficient automatic feature recognition

The CAD models of real-world mechanical parts usually have many fillets and rounds that are essentially important to ensure the manufacturability and assembability. In feature-based modeling, fillets and rounds are often refe rred as secondary features that are used to modify the local details of the primary features such as holes, slots and pockets. Although the major shap e of the primary features may not be affected, fillets and rounds can great ly change the geometric and topological patterns of the primary features. T he geometric and topological variations can result in inefficient feature s emantics classification in feature recognition. When feature interactions o ccur, it may become even worse to identify the regular patterns of the prim ary features. In addition, the fillets and rounds consist of no-linear surf aces such as cylindrical surfaces, spherical surfaces and toroidal surfaces , which bring the difficulties in volumetric feature extraction by halfspac e partition. In order to facilitate volumetric feature extraction and featu re semantics classification, we pre-process the input B-Rep models by suppr essing fillets and rounds before the feature recognition. Thus the input B- Rep models can be simplified without altering the major shapes of primary f eatures, the targets of the feature recognition. The B-Rep simplification c an be viewed as the reverse process of the edge blending in feature-based d esign. In this paper, several issues on fillet/round suppressing are discus sed and a relatively general and robust approach is proposed to suppress bl endings in B-Rep models of mechanical parts before the surface feature reco gnition and volumetric feature extraction. (C) 2001 Elsevier Science Ltd. A ll rights reserved.