| 3D model reconstruction based on point-clouds in reverse engineering has significant application in many areas. However, measurement system can not link with 3D CAD system directly because the measured dense scattered data can not be processed effectively by 3D CAD software. This is a choke point in reverse engineering. This paper researches and designs a software named Test3D. The following is the main ideas: firstly, it should become the linked part between measurement system and 3D CAD system. Then, it should can reconstruct surface from point-clouds directly in order to output surface model that can be used by CAM software directly.In this paper, the chapter 1 introduces the concept of reverse engineering, shows the position that what we research lies in reverse engineering and sketches the main content of this paper. In chapter 2, the basic functions of Test3D are described simply . Then, some basic theories about 3D graphic programming are introduced. Three key techniques are described in chapter 3. They are oriented-object, OpenGL and multithread. In chapter 4, we research a way how to generate curve by discrete points. The way uses several low-order Bezier curve to substitute one high-order Bezier curve in order to avoid computing high-order negative matrix. The curve produced by this way has good smoothness. The chapter 5 studies how to generate feature curve automatically from point-clouds. A technique that searches close points and then gets feature domain by judging the curvature. In chapter 6, we discuss the technique about surface reconstruction and present a simple and effective way. The chapter 7 introduces the basic content of iges and shows how to realize it. We concluded in chapter 8... |
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