CAD was originally the three-letter acronym for “computer aided drafting,” as in the early stage of the industry it was essentially a replacement for the traditional drafting board.

The term is now often interchanged with “computer aided design” to reflect the fact that modern CAD software does much more than just drafting — it provides a wide range of computer-based tools that assist engineers, architects and other design professionals in their design activities. All these terms are essentially synonymous, but there are a few subtle differences in meaning and application.

CAD is used to design, develop and optimize products, which can be goods used by end consumers or intermediate goods used in other products. CAD is also extensively used in the design of tools used in the manufacture of components, and in the drafting and design of all types of buildings, from small residential types (houses) to the largest commercial and industrial structures (hospitals and factories).

CAD is used for detailed engineering of 3-D models and/or 2-D drawings of physical components, but is also used throughout the engineering process from conceptual design and layout of products, through strength and dynamic analysis of assemblies, to definition of manufacturing methods of components.

CAD has become an especially important technology because it enables designers to lay out and develop their work on screen, print it out and save it for future editing, saving time on drawings.

Rather than having to build prototypes and change components to determine the effects of tolerance ranges, engineers can use computers to simulate operation to determine loads and stresses. For example, an automobile manufacturer might use CAD to calculate the wind drag on several new car-body designs without having to build physical models of each one.

In microelectronics, as devices have become smaller and more complex, CAD has become an especially important technology. Among the benefits of such systems are lower product-development costs and a greatly shortened design cycle.

A Short History of CAD

The first commercial applications of CAD were in large companies in the automotive and aerospace industries, as well as in electronics. At that time, only large corporations such as GM and Lockheed could afford the computers capable of performing the calculations.

Starting in the late 1980s, the development of readily affordable CAD programs that could be run on personal computers began a trend of massive downsizing in drafting departments in many small to mid-sized companies. One CAD operator could readily replace at least three to five drafters using traditional methods. Many engineers began to do their own drafting work, further eliminating the need for traditional drafting departments. 

The adoption of the CAD studio as a “paperless studio” in architectural schools was not without resistance. Professors were worried that sketching on a computer screen would not replicate the skills associated with the age-old practice of sketching in a sketchbook, and some were worried that students would be hired for their computer skills rather than their design skill, a practice that was common in the 1990s. Today, however, education in CAD is now accepted across the board in schools of architecture.