Computer animation with scripts and actors

Abstract

A technique and philosophy for controlling computer animation is discussed. Using the Actor/Scriptor Animation System (ASAS) a sequence is described by the animator as a formal written SCRIPT, which is in fact a program in an animation/graphic language. Getting the desired animation is then equivalent to “debugging” the script. Typical images manipulated with ASAS are synthetic, 3D perspective, color, shaded images. However, the animation control techniques are independent of the underlying software and hardware of the display system, so apply to other types (still, B&W, 2D, line drawing ...). Dynamic (and static) graphics are based on a set of geometric object data types and a set of geometric operators on these types. Both sets are extensible. The operators are applied to the objects under the control of modular animated program structures. These structures (called actor s) allow parallelism, independence, and optionally, synchronization, so that they can render the full range of the time sequencing of events. Actor s are the embodiment of imaginary players in a simulated movie. A type of animated number can be used to drive geometric expressions (nested geometrical operators) with dynamic parameters to produce animated objects. Ideas from programming styles used in current Artificial Intelligence research inspired the design of ASAS, which is in fact an extension to the Lisp programming environment. ASAS was developed in an academic research environment and made the transition to the “real world” of commercial motion graphics production.