A conceptual model for computer animation

For many years computer animations have been created using techniques that represent frames as state sets, where each frame is a function of either time or previous frames. Keyframe and goal-directed animation systems are examples of these approaches. Recently, efforts have been made to create computer animation systems that integrate multiple animation techniques. In order to facilitate this integration, a logical next step is to analyze the overlaying structure of animation systems and to develop an appropriate model. A conceptual model, and associated notation, was developed to describe the structure of computer animations, without the need to specify the specific animation techniques used. This model provides several improvements over past efforts. It is scene-based, as opposed to frame-based, and extends the definition of scenes to include both final and intermediate sequences of element state sets. Previous work either focused on frames as the primary structure or, when scene-based, addressed only rendered scenes. By basing scenes on functions that map index sequences to frames, this model allows for a more universal view of scene generation. One benefit of this is that various animation techniques, historically unique, are shown to be instances of each other. This simplifies our view of animation processes. Finally, through the use of a functional view of a scene generation process, software libraries can be created that facilitate the construction of animation programs and systems. This functional view naturally leads to the use of such techniques as object-oriented programming in the design of animations systems