Tech Report CS-88-22

BAGS: The Brown Animation Generation System

Paul Steven Strauss

May 1988


BAGS is a system for the production of three-dimensional computer animation. It is also a testbed for research into techniques used within animation systems. The combination of these aspects in one animation system is made possible by a modular design, in the center of which lies SCEFO, a general language for animation specification. SCEFO serves as the interface between the modeling and rendering components of BAGS, allowing these distinct processes to be independent. This decoupling of modeling and rendering permits a variety of modeling and rendering techniques to be incorporated in the system. The use of an object-oriented paradigm also contributes to this flexibility.

The use of BAGS as a framework for research has resulted in the development of a realistic lighting model and two extensions to the ray-tracing rendering technique. The first extension implements an area-sampling solution to the aliasing problem inherent in ray tracing, without requiring a special model or complex object intersection procedures. The second extension, which is similar in form to the first, incorporates caustics, the interplay of light between objects.

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