三维CAD模型局部结构检索属性图算法

由用户交互式地选择欲检索的模型局部结构,并自动生成该局部结构的属性图;然后取出三维CAD模型库中每个待检索模型,根据模型的B-rep表示过滤出其中与欲检索局部结构组成面相似的面,通过删除不相关面,有效地将可能相似的局部结构从待检索模型中分离出来;最后利用图论中二分图最优匹配算法计算出模型中分离出的结构和欲检索局部结构的相似系数,并将该相似系数作为实现模型局部相似性检索的依据.实验表明,该算法能够实现CAD模型局部结构检索,并与人视觉上的相似性判断基本一致.

A Partial Retrieval Algorithm of 3D CAD Models Based on Attributed Graphs

First,the sub-part,which is to be retrieved,of a 3D CAD model is selected interactively by users and its attributed graph is automatically generated.Second,for each CAD model in the database,surfaces that are similar to those of the chosen sub-part are identified.Then,other irrelevant surfaces are deleted from the model's attributed graph.Thus,the parts that are possibly similar to the sub-part are separated from the model.A method for calculating the similarity coefficient of the separated parts and the sub-part,which uses a optimal matching algorithm for bi-graphs,is proposed.Experimental results show that this algorithm can efficiently achieve partial retrieval.