Functional Implementations of Continuous Modeled Animation (expanded Version) Functional Implementations of Continuous Modeled Animation (expanded Version)

A shorter version of this report appears in the proceedings of PLILP/ALP '98, and is c Springer-Verlag. Abstract Animation is a temporally continuous phenomenon, but is typically programmed in terms of a discrete sequence of changes. The use of dis-creteness serves to accommodate the machine that is presenting an animation , rather than the person modeling an animation with the help of a computer. Using a continuous model of time for animation allows for natural speciication, avoiding some artiicial details, but is diicult to implement with generality, robustness and eeciency. This paper presents and motivates continuous modeled animation, and sketches out a naive functional implementation for it. An examination of some of the practical problems with this implementation leads to several alternate representations , all of which have diiculties in themselves, some quite subtle. We hope that the insights and techniques discussed in this paper lead to still better representations, so that animation may be speciied in natural terms without signiicant loss of performance.