Computer-aided design (CAD) is the use of a wide range of computer-based tools that support architects, engineers and other design professionals in their design activities. It is the main geometry authoring tool within the Product Lifecycle Management process and involves both software and occasionally special purpose hardware. Current packages range from 2D vector based drafting systems to 3D parametric surface and solid design modellers.

CAD is used to develop and design products, these can be goods used by end consumers or middle goods used in other products. CAD is also extensively used in the design of tools and machinery used in the manufacture of components. CAD is used throughout the engineering process from conceptual design and layout, through detailed engineering and analysis of components to definition of manufacturing methods.

Computer aided design is used in the design of tools and machinery used in the manufacture of components, and in the drafting and design of all types of buildings, from small residential types (house) to the largest commercial and industrial structures (factories and malls).

CAD is most of used for detailed engineering of 3D models and/or 2D drawings of physical components, but it 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 within the scope of computer-aided technologies, with benefits such as lower product development costs and a greatly shortened design cycle. CAD enables designers to layout and develops work on screen, print it out and save it for future editing, saving time on their drawings.

In short, with the increasing usage of computers, CAD began to be used extensively for construction related work and activities. CAD, which started with 2D services, went on and on. Now there are a range of CAD based products available in the market.