Research on Algorithm of Quadric Surface Fitting in Reverse Modeling for Mechanical Parts

To solve the problem of quadric surface reconstruction in reverse modeling for mechanical parts,a two-step fitting algorithm was presented.With this fitting algorithm,the objective function is built based on the coordinates of measuring points,the normal vector of each point and the geometrical features of mechanical part surfaces,and as a result,the nonlinear calculation of quadric fitting can be changed into a linear least square problem.Furthermore,the geometrical parameters of mechanical part surfaces can be gained through fitting calculation to provide a basis for building solid model and feature model in the reverse engineering for mechanical parts.