ABSTRACT
Free-form features find wider applications in the dies and molds, patterns and models, plastic products, automotive, aerospace, biomedical, entertainment, and geographical data processing. If free-form surfaces have such wide application, evaluation of free-form using coordinate measuring machine (CMM) is the crucial topic. One method of free-form surface evaluation is taking discrete sample points from the surface by CMM, but this sampling strategy found trade-off relationship between a number of samples and surface deviation of the actual from nominal. Moreover, the good strategy is needed that optimize this trade-off relation. In this chapter, sampling strategy based on the contour of the free-form surface is proposed to take a discrete sample by CMM form surface, since the contour curves are denser at the area with high curvature and less dense with less surface curvature which is the driving force of this method. The virtual surface is compared with the actual one. The sample points are distributed on the actual free-form surface by data point parallel projection method and iteratively sampled from the surface. A comparison is performed between the proposed method and the well-known sampling methods, which is equi-parametric method combined with mean patch Gaussian curvature method; experiment results show the effectiveness and robustness of this method.
