Methodology of NURBS surface fitting based on off-line software compensation for errors of a CMM

Off-line software measuring accuracy enhancement has been suggested based on the prediction of the measuring error, E⇀=[Ex,Ey,Ez]. Based on the error lattice, a NURBS surface can be constructed and the normals of scatter compensated points can be calculated. Then based on the normals obtained and the probe radius, the final compensated points can be determined. Let the final compensated points be target points, the desired NURBS surface can be obtained by modifying the original NURBS surface constructed by let compensated points be control points.