<P> Designers have long used computers for their calculations . Digital computers were used in power system analysis or optimization as early as proto - "Whirlwind" in 1949 . Circuit design theory, or power network methodology would be algebraic, symbolic, and often vector - based . Examples of problems being solved in the mid-1940s to 50s include: servo motors controlled by generated pulse (1949), a digital computer with built - in compute operations to automatically co-ordinate transforms to compute radar related vectors (1951) and the essentially graphic mathematical process of forming a shape with a digital machine tool (1952). These were accomplished with the use of computer software . The man credited with coining the term CAD . Douglas T. Ross stated "As soon as I saw the interactive display equipment," (being used by radar operators 1953) it would be just what his data reduction group needed . With the Lincoln Lab people, they were the only ones who used the big, complex display systems put in for the pre-SAGE, Cape Cod system . But "we used it for our own personal workstation .". The designers of these very early computers built utility programs so that programmers could debug programs using flow charts on a display scope with logical switches that could be opened and closed during the debugging session . They found that they could create electronic symbols and geometric figures to be used to create simple circuit diagrams and flow charts . They made the pleasant discovery that an object once drawn could be reproduced at will, its orientation, Linkage (flux, mechanical, lexical scoping) or scale changed . This suggested numerous possibilities to them . It took ten years of interdisciplinary development work before SKETCHPAD sitting on evolving math libraries emerged from MIT's labs . Additional developments were carried out in the 1960s within the aircraft, automotive, industrial control and electronics industries in the area of 3D surface construction, NC programming and design analysis, most of it independent of one another and often not publicly published until much later . Some of the mathematical description work on curves was developed in the early 1940s by Robert Issac Newton from Pawtucket, Rhode Island . Robert A. Heinlein in his 1957 novel The Door into Summer suggested the possibility of a robotic Drafting Dan . However, probably the most important work on polynomial curves and sculptured surface was done by Pierre Bézier, Paul de Casteljau (Citroen), Steven Anson Coons (MIT, Ford), James Ferguson (Boeing), Carl de Boor (GM), Birkhoff (GM) and Garibedian (GM) in the 1960s and W. Gordon (GM) and R. Riesenfeld in the 1970s . </P> <P> The invention of the 3D CAD / CAM is attributed to a French engineer, Pierre Bézier (Arts et Métiers ParisTech, Renault). After his mathematical work concerning surfaces, he developed UNISURF, between 1966 and 1968, to ease the design of parts and tools for the automotive industry . Then, UNISURF became the working base for the following generations of CAD software . </P> <P> It is argued that a turning point was the development of the SKETCHPAD system at MIT by Ivan Sutherland (who later created a graphics technology company with David Evans). The distinctive feature of SKETCHPAD was that it allowed the designer to interact with his computer graphically: the design can be fed into the computer by drawing on a CRT monitor with a light pen . Effectively, it was a prototype of graphical user interface, an indispensable feature of modern CAD . Sutherland presented his paper Sketchpad: A Man - Machine Graphical Communication System in 1963 at a Joint Computer Conference having worked on it as his PhD thesis paper for a few years . Quoting, "For drawings where motion of the drawing, or analysis of a drawn problem is of value to the user, Sketchpad excels . For highly repetitive drawings or drawings where accuracy is required, Sketchpad is sufficiently faster than conventional techniques to be worthwhile . For drawings which merely communicate with shops, it is probably better to use conventional paper and pencil ." Over time efforts would be directed toward the goal of having the designers drawings communicate not just with shops but with the shop tool itself . This goal would be a long time arriving . </P> <P> The first commercial applications of CAD were in large companies in the automotive and aerospace industries, as well as in electronics . Only large corporations could afford the computers capable of performing the calculations . Notable company projects were, a joint project of GM (Patrick J. Hanratty) and IBM (Sam Matsa, Doug Ross's MIT APT research assistant) to develop a prototype system for design engineers DAC - 1 (Design Augmented by Computer) 1964; Lockheed projects; Bell GRAPHIC 1 and Renault . </P>

Cad is used to create products in many different fields