Source: Wikipedia.org

Computer aided design (CAD) is the use of computer technology for the design of objectsl . The design of geometric modelssuch as technical drawing for object shapes, in particular, is often called computer-aided geometric design (CAGD).

However CAD often involves more than just  a shapes. As in the manual drafting of technical and engineering drawings, the output of CAD often must convey also symbolic information such as materials, dimensions, and tolerances, according to application-specific conventions.

CAD may be used to design curves and figures in two-dimensional 2D space; or curves, surfaces, or solids in three-dimensional (3D) objects.

CAD is an important industrial art extensively used in many applications, including automotive, shipbuilding, and aerospace industries, industrial and architectural design, prostethics, and many more. CAD is also widely used to produce computer animation for special effects in movies, advertising, technical manuals.  Because of its enormous economic importance, CAD has been a major driving force for research in computational geometry, computer graphics (both hardware and software), and discrete differential geometry.