Research On Triangulation Technology In Reverse Engineering

Reverse engineering is one important way of product creative development and rapid manufacture, which is widely used in automobile, home appliances, mould, entertainment and medical treatment. As the key technology of reverse engineering, triangulation is always a hot research topic. Triangulation can directly change point data into entity model. Entity models from triangulation mesh can be manufactured into samples or moulds, which can shorten products'manufacture time and design period to realize the production of small batch and many varieties. Furthermore, there are entity models created by polygon mesh in many applications such as cartoon,vision environment,network browse,physic scanning,computer games. For the issues of theory of triangulation and its applications, several key technologies of triangulation are systematically studied and implemented in this dissertation. In this thesis data points are classified into touched data points and untouched data points by the approach how to get them. Data points are also classified into scattered points, grid points, scanned lines, feature points and lines by their distributing feature. Sampled points are processed, which include editing points cloud, constructing points cloud , inquiring character of points cloud. The thesis puts forward the character and research content of surface reconstruction, introduces basic concepts and theories such as Voronoi map and Delaunay triangulation, rules that optimize mesh, triangulation in the 2D plane. Finally the thesis particularly discusses local Delaunay triangulation arithmetic, growing triangulation arithmetic and spiraling triangulation arithmetic, include their realization, advantages and disadvantages. A new arithmetic, an improved spiraling edge triangulation arithmetic, is put forward and realized in the HT-ReSurf system. The new arithmetic uses the concept of "neighbor points", grows new outwards triangles according to boundary circle of the spiraling edge triangulation arithmetic, searches neighbor points of boundary edge by encircling box arithmetic, and properly adds natural neighbors onto boundary edge. Thus, the improved arithmetic not only avoids putting mesh together, but also finds natural neighbors. The triangulation mesh is basically the optimization Delaunay mesh. The thesis compares and analyses running rapidity, triangulating result, overlapping and hole of mesh and other performance index. The experiment results prove that the new arithmetic has some application value. Finally,the reverse engineering CAD modeling software HT-ReSurf is designed and realized to overcome the disadvantages of general CAD/CAE/CAM systems and special reverse engineering software. All of the data processing researches in this article, include editing points cloud, constructing points cloud, inquiring character, have been implemented in HT-ReSurf system with applications.