Research Of Reconstruction Of Curve And Surface In Reverse Engineering

3D model reconstruction based on point-clouds in reverse engineering has significant application in many fields. 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. A software named Test3D is researched and designed in this paper. The following is the main ideas: firstly, it should become the linked part between measurement system and 3D CAD system. Then, it 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 presents the application background, constitute, principle and application field of engineering technique. In particular, it explains in detail the methods of each step of reserve engineering technique in product development, i.e. object digitization, object modeling and object manufacturing, and sketches the main content of this paper. The chapter 2 studies how to generate feature curve automatically from point-clouds. Without any additional information other than co-ordinates of the measured points, the curvature value of a point is finally obtained by the adjacent domain of this point. Then the feature domain of Data Clouds is gotten. In chapter 3, the methods how to generate curve by discrete points are researched. Based on the feature domain of Data Clouds obtained in the former chapter, this chapter gets its feature points. Finally free-form curves interpolated through these feature points are produced. The chapter 4 discusses the technique about surface reconstruction. An effective algorithm combining the idea of B-spline method and Bezier method is proposed. These surfaces are C2 continuous between patches. The last chapter makes a conclusion.