Reverse Engineering Surface Reconstruction

Presently, the drastic competitiveness in market, which make the products life cycles shorter and shorter, requires rapidly responding for enterprise. In industry design, the free-form shapes cannot be properly described in 3-D views so that the CAD models cannot be created. But reverse engineering (RE) technology can shorter the product development time, improve competitiveness, and overcome the special difficulties in industry design for free-form shapes. Based on the full analysis of the fields of the present research on the reverse engineering with home and foreign documents this paper take 3-D surface reconstruction for the key and crucial technology of CAD modelling of RE and accordingly do some in-depth research about interactive modelling of 3-D surface reconstruction.In this paper, the network method of surface reconstruction, in which how to program the framework line, is proposed. The framework line should created in lower degree and a small number of control points so that the created surfaces from them are smoothness. It should be throw G1 continuity at least between framework lines in order to realize fairness connection. For the random scatter point's surface fitting this paper classified it as two types: surface approximated directly from point clouds and surface interpolated from curves that created from selected points, and further more how to perform surface reconstruction by each kind of surface fitting method and in which situation it should be used are outlined.A new method of surfaces connection is introduced, and the key factor about surface connection is how to select the surface boundary line and the tendency of the connected surface. And then how to diagnose the quality of final surface models and what method is applied are outlined. Furthermore this paper tries to optimize parameter, control point, knots vector and degree that controlled the free-form shapes fitting or interpolation.How to solve general difficulties in engineer, such as disappeared surface reconstruction, triangle surface reconstruction and Y shape surface reconstruction are also outlined. And the distortion in lofting surface is analyzed, and how to solve the problem is also outlined.In the end all stated in this paper was applied to "JiaBao" automobile body out surface reconstruction, by further forward designing realize technology innovation. It is proved that the application is performed efficiently and practicality.