Historical Perspective on CAD
Graphical representation of data, in many ways, forms the basis of CAD. An early application of computer graphics was used in the SAGE (Semi-Automatic Ground Environment) Air Defense Command and Control System in the 1950s. SAGE converted radar information into computer-generated images on a cathode ray tube (CRT) display. It also used an input device, the light pen, to select information directly from the CRT screen.
Another significant advancement in computer graphics technology occurred in 1963, when Ivan Sutherland, in his doctoral thesis at MIT, described the SKETCHPAD system (Fig. 1). A Lincoln TX-2 computer drove the SKETCHPAD system. With SKETCHPAD, images could be created and manipulated using the light pen. Graphical manipulations such as translation, rotation, and scaling could all be accomplished on-screen using SKETCHPAD. Computer applications based on Sutherland’s approach have become known as interactive computer graphics (ICG). The graphical capabilities of SKETCHPAD showed the potential
for computerized drawing in design.
During his time as a professor of electrical engineering at the University of Utah, Sutherland continued his research on head-mounted displays (HMDs). The field of computer graphics, as we know it today, was born from among the many new ideas and innovations created by the researchers who made the University of Utah a hub for this kind of research. Together with the founder of the university’s Computer Science Department, Sutherland cofounded Evans and Sutherland in 1968, which later went on to pioneer computer modeling
systems and software. Today, almost 40 years later, the company remains an industry leader in developing both hardware and software to help professionals create realistic images used in a variety of applications such as simulation, training, and engineering (Fig. 2).
While at the California Institute of Technology, Sutherland served as the chairman of the Computer Science Department from 1976 to 1980. While he was there, he helped to introduce the integrated circuit design to academia. Together with Carver Mead, they developed
the science of combining the mathematics of computing with the physics of real transistors and real wires and subsequently went on to make integrated circuit design a proper field of academic study.
In 1980, Sutherland left Caltech and launched the company Sutherland, Sproull, and Associates. Bought by Sun Labs in 1990, the acquisition formed the basis for Sun Microsystems Laboratories.
The high cost of computer hardware in the 1960s limited the use of ICG systems to large corporations such as those in the automotive and aerospace industries, which could justify the initial investment. With the rapid development of computer technology, computers became more powerful, with faster processors and greater data storage capabilities. Their physical size and cost decreased, and computers became affordable to smaller companies and personal users. Today it is rare to find an engineering, design, or architectural firm of any size without a working CAD system running on a personal computer (PC) or a workstation.
Emory W. Zimmers, Jr. and Technical Staff
Enterprise Systems Center
Lehigh University
Bethlehem, Pennsylvania
Mechanical Engineers’ Handbook: Materials and Mechanical Design, Volume 1, Third Edition.
Edited by Myer Kutz
Copyright 2006 by John Wiley & Sons, Inc.
