Grammar-based Incremental Generation of 3d-animation Scripts and Its Generic Implementation in Lisp

This paper describes the automatic generation of 3D animation sequences within the Cathi 1 system, expressing given communicative contents based on a grammar-like system of visualization rules. It emphasizes the view of animation generation as a process that bears similarities with the generation of natural language and allows, to a certain extent, the transfer of ideas and methods from this eld. The generation process works incrementally to allow an interactive presentation system to generate animations and show them with a limited delay, which is important for short system response times. We will show which type of incrementality is supported by the inherent structure of animation scripts and describe an eecient and generic implementation of the generation process in LISP. Depending on the available graphical output devices and facilities the system may produce animation scripts for simple wire-frame graphics or sophisticated lighting and shading models. The availability of such features as color or spotlights is already considered in the process of script generation. This allows optimal use of the available