YACAS : a batch computer animation system

Abstract

This thesis describes the design and implementation of a computer animation system called YACAS. YACAS is a batch animation system consisting of two parts. One part is a set of subroutines written in Burroughs Extended ALGOL that provide a number of functions for use by an animator in preparing a program to make an animated film. The second part is a program which the animator can use to interactively display and record his film. Pictures produced by the system are 2 dimensional "wire-frame" images in black and white. In YACAS the data structure recognizes a distinction between the shape of a picture (referred to as a “cel”) and other picture attributes (position, size, etc). Pictures may be "simple" or may be joined and manipulated as a hierarchical group called an "articulated" picture. A small number of commands have been provided to allow motions of pictures and the display window to be described. A mechanism is provided to allow the user number of motions to add new motion commands. An arbitrary number of motions may be flexibly combined to produce concurrent asynchronous motions. A compact form of film file is produced by the user's animation program which can be displayed with the interactive playback program. The main body of the thesis describes YACAS as it has been designed and implemented. The last chapter of the thesis describes a number of enhancements that would make YACAS more versatile. Appendix A is a complete User Guide for the system, while Appendix B gives an example of the programming and use of the YACAS subroutines.