Beautiarch

Before computers were widely available, most mechanical, civil and electrical drawings were sketches or drawn by hand using drafting tools. This was a time consuming process and it was difficult to make corrections easily.  As the use and availability of  personal computers increased,  Computer aided Drafting (CAD) packages greatly reduced the time and effort needed to make drawings.

Though the term CAD was initially used for Computer Aided Drafting , it is now widely used to denote Computer Aided Design, for which drafting of  drawings is one aspect. CAD is widely used for the design of  mechanical components, tools and machinery.  It is also used for design of buildings and preparation of  building layouts. Drawings usually indicate the scale used otherwise are specified as NTS (not to scale)

Many times, CAD is combined with computer aided manufacturing (CAM) as the mechanical drawings prepared while designing a component can be directly fed to the CNC machine used to manufacture the part.