Computer-aided design is essentially based on a versatile and powerful technique called
computer graphics, which basically means the criterion and manipulation of pictures on a
display device with the aid of a computer. Computer graphics originated at the Massachusetts
institute of technology (MIT) in 1950when the first computer-driven display, linked to a Whirlwind
1 computer, and was used to generate some pictures. The first important step forward in
computer graphics came in 1963 when a system called SKETCHPAD was demonstrated at the
Lincoln Laboratory of MIT. This system consists of a cathode ray tube (CRT) driven by TX2
computer. The CRT had a keyboard and a light pen. Pictures could be drawn on the screen and
then manipulated interactively by the user via the light pen.
This demonstration clearly showed that the CRT could potentially be used as a designer’s
electronic drawing board with common graphic operations such as scaling, translation, rotation,
animation and simulation automatically performed at the ‘push of a button’. At that time, these
systems were very expensive; therefore they were adopted only in such major industries as the
aircraft and automotive industries where their use in design justified the high capital costs.
Another crucial factor preventing computer graphics from being generally applied to engineering
industries was that there was a lock of appropriate graphics and application software to run on
these systems. However, a computer-based design system was clearly emerging. Since these
pioneering developments in computer graphics, which had captured the imagination of the
engineering industry all over the world, new and improved hardware, which is faster in
processing speed, larger in memory, cheaper in cost and smaller in size, have become widely

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