A Loop Segmentation Based Approach To Automatic Reconstruction Of Design Features For B-rep Models

Feature based 3D modeling can better represent the design intent, and modify the part model efficiently. Design by features is the main method of the current product design. However, due to lack of international or industry standard on feature information exchange, the part models from heterogeneous platforms can only exchange their lower-level geometric information. As a result, the transformed model cannot be edited and redesigned by using the original feature information. Research on the automatic recognition of design features and the reconstruction of the design feature model from geometric boundary models has important practical value.At first, the theory and methods on solid boundary model, CSG model, feature representation, and feature modeling process are studied in depth. The shape feature and shape evolution in the feature modeling process are analyzed. A loop segmentation based approach to automatic reconstruction of design features for B-rep models is proposed. This approach first recognizes the segmenting loops from B-rep models, and then constructs the swept design features based on the face shell collected by the recognized segmenting loops. The generation principle and the existence area of swept features are analyzed, which lay the foundation for the following feature recognition. Parasolid API function is used to extract the topological and geometrical information of the entity model, and the face attribute adjacency graph of the model is created. A set of segment loop sequences is obtained by topological sorting of the segmentation loop graph. The design feature of the model can be obtained by the feature recognition of the solid model using the segment ring sequence. Finally, the relationship graph of the design feature is created, and the design history structure tree of the model is constructed by using graph partitioning.Based on the above theory and algorithm, this paper employs the object oriented programming technology and has realized the approach presented in this paper on the JHSOLID platform. Example tests demonstrate the effectiveness and feasibility of the method presented in this paper.