关键词: 递归分割, 机械零件, 满二叉树, 三维形状结构检索, 设计重用, 相似度比较

Abstract: To realize reusable design, the retrieval of existing engineering design cases is necessary in which the most difficult problem is shape similarity comparison. Therefore, a 3D shape and structure retrieval method of mechanical parts based on recursive segmentation is put forward. The initial position of mechanical parts is obtained by generating convex bounding box of the mechanical parts and the normalization transformation of mechanical parts is realized. The solid model is segmented by generating adaptive bounded segmentation plane. The ordered full binary tree is built through recursive algorithm with the change detection of both the geometry and topology of the model. The feature vectors combined with engineer features are constructed to obtain the similarity comparison of the solid model in non-root nodes by means of similarity comparison of the vectors. The breath-first and variable weight traversal of the ordered full binary tree is realized. The similarity of 3D shape and structure between the mechanical parts is obtained via the similarity comparison of the solid model in non-root nodes. The application and verification of 3D shape and structure retrieval method of mechanical parts based on recursive segmentation in prototype system indicates that the method has higher calculation efficiency and judgment precision and it can reflect not only the global sketchy shape but also the local detail structure of the mechanical parts. It has important significance to realizing design reuse and improving design efficiency.

Key words: 3D shape and structure retrieval, Design reuse, Full binary tree, Mechanical parts, Recursive segmentation, Similarity comparison