Artifacts in Box-Spline Surfaces

Certain problems in subdivision surfaces have provided the incentive to look at artifacts. Some of these effects are common to all box-spline surfaces, including the tensor product B-splines widely used in the form of NURBS, and these are worthy of study. Although we use the subdivision form of box- and B-splines as the mechanism for this study, and also apply the same mechanism to the subdivision schemes which are not box-splines, we are looking at problems which are not specific to subdivision surfaces, but which afflict all Box- and B-splines.