CADSYS: A New Approach to Computer-Aided Design

This paper presents a first implementation of a computer-aided design concept intended to confront issues normally faced by designers of complex engineering systems. Computer graphics play no essential role in this concept. Rather, the concept is aimed at organizing the analysis and search activities of a designer as he attempts to find values for the independent design parameters at his disposal so that specific performance goals will be met. The framework for the implementation is an interactive computer system written in PL/I, comprising a problem-independent command interpreter and a completely general problem-dependent analytical statement relating the design parameters and the performance measures. The designer can change the performance specifications (and to a limited degree the analytical problem statement itself) and can issue commands directing searches for solutions (values for the independent parameters) that satisfy, or come closest to satisfying, the requirements. If the requirements conflict and admit of no solution, he can relax them in an organized fashion. If they are slack and admit many overdesigned solutions, he can search for ways to tighten them or to balance the achievement of them. A manager can assign several designers to use computer-aided design system (CADSYS) simultaneously to work on related parts of a large problem. Changes or results by one designer are immediately felt by the others and by the manager. CADSYS thus has some of the properties of a management information system.