汽车逆向设计中用NURBS曲面拟合点云数据

针对汽车的逆向设计,利用非接触测量方法中的CDD相机拍照法得到一组点云数据·将Tritop,Atos和CATIA三种软件联合应用,对点云数据进行了筛选、划分,用曲线拟合的方法做出了点云的特征线网格,并在此网格的基础上,利用NURBS曲面拟合技术,得出了点云的曲面造型·通过将拟合得到的曲面造型和原始点云数据的对比,对拟合曲面进行了误差分析·结果显示,只是在凹槽的边缘部位误差稍有增大,但也在很小的范围内变化,符合实际设计时的要求·由此证明,此种多软件联合应用的方法在处理曲面造型的逆向设计方面是可行的·

Point Cloud Fitting of NURBS Curved Surface in Reverse Design of Automobiles

A group of point cloud data is obtained by way of no contact CDD photogrammetry for reverse design of automobiles. The point cloud data are screened and classified with combining the three softwares together, i.e., Tritop, Atos and CATIA, thus making a characteristic curve net for the point cloud data by curve fitting technique. Then, a relevant curved surface is shaped using the fitting technique of NURBS curved surface. Comparing the curved surface thus shaped with the original point cloud data, the errors of the curved surface are analyzed and the result shows that only the error at recess edge increases a bit in a very small range. It conforms with the actual requirement for design. The way applying several softwares in combination to curved surface shaping is therefore proved available to reverse design of automobiles.