Research And Implementation Of 3d Vertor Graph Cutting And Splitting Algorithm

At present, Visualization in Scientific Computing is a hot direction in computer graphics. Cutting and slitting function as one of the key and core functions in scientific visualization is widely used in the natural sciences and engineering aspects. The vector graphics suitable for all kinds of objects have been widely applied. Based on the introduction and analysis of the characteristics of various vector models, this thesis mainly put forward research and outlines the creation concerning the following two issues: Firstly, trimming algorithm based on Triangle Mesh. Secondly, vector Model cutting Algorithm for B-Rep model.In the aspect of trimming algorithm based on Triangle Mesh, this paper presents a new triangular mesh cutting algorithm. This algorithm first uses the planar parameterization method to project the 3D surface to the two-dimensional space. Then it calculates the corresponding cutting way. Based on this way, it cuts triangle mesh. Finally, the algorithm restores triangle mesh to 3D space. When searching the cutting way, this algorithm uses the algorithms of point fast position in triangle mesh, and Obtains triangles which the cutting way's vertexs are in, then according the topology between triangles, all intersect lines can be obtained quickly.In the aspect of vector Model cutting Algorithm for B-Rep, this paper proposes an improved plane spliting method. This method firstly gets the intersect lines between solid and cutting plane, then creates contours and their relationship of enclosure is ascertained. At last, the region enclosed by the contours is triangulated. Because the plane splitting cannot satisfy Actual demand, this thesis proposes a ladderlike splitting method. The principle and approach for ladderlike splitting are described in detail including profile formation, solid division and solid reconstruction. All kinds of critical instances are discussed, and the solve method is given to ensure the result's correctness. It improves the algorithm usability. Meanwhile, this method introduces collision examines algorithm before seeking intersect points, avoids unnecessary intersecting operation. This thesis at last proposes the mentality and the step in surface cutting.