VEGA: a Geometric Modelling System

VEGA is a program which models rigid solid objects in three dimensions. Specifically, its domain is assemblies of planar faced polyhedra. VEGA supports a variety of operations to create, modify, query and delete these assemblies. VEGA is intended to serve two purposes: that of a new medium of representation for the design process, and of a programming package to support geometric applications in a wide variety of domains. Here the author addresses primarily the first of these purposes, that of a new medium for design. Designers of physical objects use an external medium, traditionally paper or physical models, not only to record their work, but to provide information which assists in the understanding of implications of design decisions. Designers proceed by performing operations, which reflect internal design decisions, on this external medium. The operations used in design are generally reflective of these physical media. For example, models built of clay tend to be formed by a subtractive processes, whereas models built of wood tend to be additive in nature. Designers who use drawings as their medium still tend to use operations which reflect operations on physical models. Computers provide the fascinating potential to provide a much wider variety of operations at a much greater speed than is available with the traditional means of representation. In addition, a computer based representation can provide quantitative information not easily accessible from traditional forms. This opens the potential for the inclusion of formal means of evaluation in the design process, something which is generally almost absent in traditional design teaching. A computer program which effectively and'naturally'models physical objects and operations on them would be a valuable assistance to both the teaching and practice design. VEGA has been designed with these objectives in mind. VEGA represents physical objects with a scheme known as boundary representation and provides a wide variety of operations on these objects. VEGA also provides means to associate other, non-geometric, information with the objects it represents. VEGA is implemented under the ANDREW system. It communicates to ANDREW through a graphics package, also developed by the author's group. VEGA is intended to serve as a medium for future studio courses in the Architecture, Industrial Design and Arts educatio