Research And Implementation Of Shoe Pattern Surface Parametric Technology Based On Feature Lines

The shoe pattern surface modeling is important to shoe pattern design, even the shoe industry. Simultaneously, parametric CAD is one of trends in computer-aided design. On the basis of the analysis of its status quo and the problems remained, a new shoe pattern method surface modeling based on feature lines is put forward in this dissertation, which can significantly improve the automation degree and efficiency of enterprises.The first problem is how to generate the pattern surface after the shoe last was modeled. In chapter 2, feature points are detected based on the essential characters of the last; feature lines are generated according to the feature points at the first. Then an algorithm to detect special region divided by the feature lines is presented. At last, shoe last surface is sliced and triangulated by the feature lines. To develop the efficiency of triangulation, an algorithm to determining the Convexo-concave vertices of polygon by topological mapping is put forward.Parametric design has been a hotspot in the area of CAD technology. Parametric design is extended to high-level entities that include 3D curve and 3D surface to solve the parametric editing shoe pattern surface on one last surface in the chapter 3. The Geometric Constraint Graph (GCG) of the feature lines are established automatically in the first, then an algorithm to solve the GCG based on Constraint Reasoning and Graph Theory is presented. After all constraints are satisfied, the shoe pattern surface is regenerated by new feature lines.One of the basic problems of Shoe-CAD is how to reuse the outstanding patterns designed by the designer, so the chapter 4 extends the parametric design technology to reuse the shoe pattern on various lasts. A method to solve this problem via the following aspects: and topological un-homeomorphous lasts. The topological un-homeomorphous lasts can be converted to the topological homeomorphous lasts via topological equivalent transformation first, then the feature lines are mapped from one last to another one, at last, the shoe pattern surface can be reconstructed by the new feature lines and the informationof the old shoe pattern surface.Based on the research work above all, an "EGI-Shoe CAD" is introduced in chapter 5, including its buildup, structure and main functions, also with some examples. Finally, the development of "EGI-Shoe CAD" is summarized and the future work is put forward.