Reverse engineering of composite sculptured surfaces

A reverse engineering technique is proposed in this study for modelling composite sculptured surfaces. The proposed technique includes a sur;face fitting algorithm and a surface blending algorithm. The former is formulated as the least-squares minimisation problem for which an error expression was minimised which yields the optimised position of control points and parameter values for the non-uniform rational B-spline patch. Cubic spline and bicubic surface algorithms are developed for true-patch and four-patch blending, respectively. Computer simulation results clearly demonstrate that the proposed technique is useful for composite surfaces modelling applications. Factors affecting the convergence speed and surface accuracy in the optimisation process are also discussed.