The Concise Structuring of Geometric Data for Computer Aided Design

Publisher Summary This chapter focuses on the concise structuring of geometric data for computer aided design. A physical system is a collection of parts that occupy space and whose performance is a function of their spatial composition. Buildings, automobiles, ships, and aircraft are usually considered during design as physical systems while computers and electronic systems are usually not. The bottom level description of a physical system in a design information system (DIS) is a collection of elements. Each element consists of a set of attributes, including shape, cost, structure, and function. Millions of bytes are often required to hold such a description, which currently encourages use of some form of secondary memory. The definition of a physical system description of such a large size is a difficult and time consuming task. The standard procedure for building up a description in a DIS is to transfer part descriptions from disc or tape files comprising the parts catalog into the project file.