|
A group of geometric primitives based on polynomial patches. Patch primitives are the most versatile of the primitives supported by the rendering library and are able to encompass all common formats used in CAD/CAM systems, such as bi-linear, bi-cubic, Bezier, and B-spline patches. All patches may be created in rational or nonrational form. If a patch is rational, then control point coordinates must be provided in homogeneous form (wx,
wy,
wz,
w) where
w is the weight. The weight determines the relative influence of a control point on the spline.
|