Hierarchical B-splines are animated either by manipulating control vertices, or by attaching the surface to an articulated skeleton. The surface may be attached at any level in the multi-resolution representation. Thus large scale deformations that span joints is simple and easy to do. This technique not only reduces the number of operations needed to animate the surface, but because surface details follow the basic shape of the surface, they do not have to be directly animated.
15) An animated human knee
16) An animated human knuckle
17) Closeup of knuckle showing folds in skin.
18-20) Examples of surfaces animated by attaching the surface to an underlying skeleton. In these figures only the underlying skeleton has been manipulated, no other editing of the surface shape was used.
21-26) The surfaces in these figures were created by Goesta Struve-Dencher . (Imager's staff animator.. the staff don't need to be any more animated! :) The eye is a good example of how easy it is to animate hierarichal B-spline surfaces... to animate the surface to open and close the eye is about a 10 minute exercise.
Last updated by David Forsey on 1 Feb. 95.