Modeling free form surface accurately is necessary precondition for cam high-precision reverse. The point cloud is achieved by measuring free surface via coordinate measuring machine(CMM). Efficient removing algorithm of noisy points

smoothing technology of boundary points and the whole points

filtering of point cloud and expanding of the surface are focused on. Finally

the rapid and precise modeling of high density point cloud in UG environment is realized by combining with VC data processing and UG/Open secondary development tool. The method is tested to improve the efficiency and accuracy of free form surface modeling.