Computer Aided Design (CAD) systems describe software systems capable of creating, modifying and analyzing an engineering design. This involves computers to aid in the process of product design and development.
CAD originated from early computer graphic systems, and evolved with the development of interactive computer graphics and geometric modelling . The development of Sketchpad system at MIT in 1963 by Dr. Ivan Sutherland was the turning point in the development of CAD systems. Sketchpad was the first system that allowed a designer to interact with a computer graphically by drawing on a cathode ray tube (CRT) monitor with a light pen.
In the early 1970s CAD systems were little more than drafting software used to create 2D drawings, limited to simple geometry, such as lines, circular arcs and ellipse arcs. Therefore they were often reffered to as computer aided drafting. Advances in programming and computer hardware, notably, solid modeling in the 1970s, made the CAD applications more versatile. CAD further evolved with the development of geometric modeling based on the mathematical description of geometry, from simple two-dimensional (2D) drafting to three-dimensional (3D) wire frame, to 3D surfaces and now three-dimensional (3D) wire frame, to 3D surfaces and now 3D solid modeling. Geometric modeling enables creation of new geometric models. Geometric modeling enables creation of new geometric models from the inbuilt blocks available in the system, moving the images around on the screen, zooming in on a certain feature, and so on. CAD systems are now being extensively used throughout the engineering process from conceptual design and detailed engineering, to dynamic analysis of components and assembly planning.
Computer aided design is a faster and more accurate method of engineering design than the convectional methods. This has become possible through the following benefits offered by CAD systems:
- Increased design productivity.
- Increased available geometric forms.
- Improved quality of design.
- Improved communication documentation.
- Creation of manufacturing data base.
- Design standardization.