A Mathematical Model for Mechanical part Description The flexibility of a mathematical model takes advantage of the common information requirements of computer-aided engineering drawing, numerical control tape generation, and physical characteristic computation. By judicious control of man-machine communication requirements, improved results over conventional engineering design processes are possible. An English-like input language, tailored for use by draftsmen and designers, will describe the part and specify the output desired. One approach to the mathematical model consists of a group of surface-defining quadric equations, which are created by a system of modular subprogram. Other subprograms will convert the mathematical model into instructions for driving automatic drafting machines and numerical controlled machine tools. Physical part characteristics, such as center of gravity, can be computed by subprograms and used in dynamic analysis work. The proposed overall system is presented and experiments and demonstrations are discussed. CACM February, 1965 Luh, J. Y. S. Krolak, R. J. CA650216 JB March 7, 1978 10:46 PM 1308 5 1308 1308 5 1308 1308 5 1308