Research On Blank Generation Based On Lightweight Model

With the rapid development of CAD / CAM technology,the application of three-dimensional software is more and more common,the three-dimensional model has gradually become the core carrier of product information.Three-dimensional model is getting bigger and bigger,especially for complex machine production.and 3D models are very inefficient in the information transmission,interactive browsing and sharing.The lightweight model has been widely used in three-dimensional process because of its small amount of data and fast browsing efficiency.But the lightweight model is difficult to edit and modify and is difficult to realize the generation of the blank model in the three-dimensional processing technology.And the blank model plays an important role in the three-dimensional process planning.In view of this situation,this paper studies the blank generation technology based on the lightweight model.According to the relationship between the data characteristics of the lightweight model and the triangular surface,the surface of the lightweight model is segmented.The lightweight model is separated into a series of triangular patches corresponding to the geometric topological surface of the part.The general geometric characteristics of the discrete surface set are analyzed,then its geometric features are extracted to match typical geometric feature element,andthe plane,the cylindrical surface,the spherical surface,and the cone surface are identified.The geometry relation of triangle in the lightweight model surface is analyzed,then the set of identified boundary edges are extracted,then the boundary loop of the surface are constructed,and the topology of surface and edge are reconstructed based on triangle.and the concavity and convexity of the edges in the face map are identified,and the face map with concavity are constructed.The concave subgraphs of the face map are extracted,then compared with the topological structure of typical feature plane.The recognition of typical processing features in lightweight files is accelerated and the foundation for feature identification based on the face map of lightweight model is laid.Through interactive feature recognition and based on the topological structure of the face maps,by removing and translating the association surface of the machining feature in the lightweight model,and then the hole arecreated after the face is deleted is triangulated.and then the generation of the blank and the intermediate part model is achieved.Based on HOOPS platform,the blank generation of lightweight model is achieved.