Research On Methods Of Modeling For Automobile Based On Sqrt 3 Subdivision

Reverse engineering technology in the the computer-aided geometric design of automobile body has been widely used,but the replacement of model has been more and more rapid,the geometric efficiency and the quality of the body surface has been put forward a higher demand.Therefore,to explore the method the rapid generation of vehicle body geometry surface has important significance.In this paper,automobile body modeling technology of the sqrt 3 subdivision surfaces were reasearched,the main contents are as follows:Firstly,an overview of the algorithm of simplification domestic and abroad were provided,some existing algorithms of simplification were summarized and researched;and existing methods of subdivision were studied and some classic algorithm of subdivision were analysised and summarized.And the advantages and disadvantages and the scope of application of these methods were pointed out.Secondly,simplification algorithm of edge collapse based on the quadric error measure(QEM)proposed by Garland were reasearched,and a mesh simplification algorithm maintain the characteristics of the border was realized that can quickly and accurately simplify the model of mesh;sqrt 3 subdivision was studied and achieved,a new sqrt 3 subdivision maintaining the characteristics of the border was proposed.Compared with the typical subdivision method,it has he advantages of good continuity,good controllability;At last,with the development tool Visual C++6.0 and UG/OPEN API, subdivision based on simplification algorithm of edge collapse was realized,was applied to surface modeling for automobile body,and a pre-processing system of body point cloud was constructed.Besides,the results of application were compared with the original meshes and analysised.The experimental results show that simplification algorithm based on quadric error metric and sqrt 3 subdivision algorithm has greate value for the multi-resolution surface modeling of automobile body.