Definition

Computer-aided design (CAD) is a computer technology that designs a product and documents the design’s process. CAD may facilitate the manufacturing process by transferring detailed diagrams of a product’s materials, processes, tolerances and dimensions with specific conventions for the product in question. It can be used to produce either two-dimensional or three-dimensional diagrams, which can then when rotated to be viewed from any angle, even from the inside looking out. A special printer or plotter is usually required for printing professional design renderings. The concept of designing geometric shapes for objects is very similar to CAD. It is called computer-aided geometric design (CAGD). CAD is also known as computer-aided design and drafting (CADD).

echopedia explains Computer-Aided Design (CAD)

CAD is used as follows:

1. To produce detailed engineering designs through 3-D and 2-D drawings of the physical components of manufactured products.
2. To create conceptual design, product layout, strength and dynamic analysis of assembly and the manufacturing processes themselves.
3. To prepare environmental impact reports, in which computer-aided designs are used in photographs to produce a rendering of the appearance when the new structures are built.

CAD systems exist today for all of the major computer platforms, including Windows, Linux, Unix and Mac OS X. The user interface generally centers around a computer mouse, but a pen and digitizing graphic tablet can also be used. View manipulation can be accomplished with a spacemouse (or spaceball). Some systems allow stereoscopic glasses for viewing 3-D models.

Plotter

Definition

A plotter is a computer vector graphic printer that gives a hard copy of the output based on instructions from the system. Plotters are widely used to print designs of things such as cars, ships and buildings on a piece of paper using a pen. Plotters are different than a printer in that they are more precise and they are most commonly used in engineering, where precision is mandatory. They are also more expensive than ordinary printers. A plotter is also known as a graph plotter.

echopedia explains Plotter

Plotters are widely used in engineering projects because they can produce continuous lines, in contrast to ordinary printers that conventionally drew lines using closely spaced dots. Plotters come in various forms. Most plotters use a pen to draw the design onto paper. However, a 3-D plotter (cutting plotter) uses knives to cut out a piece of material based on instructions from the computer. The object to be cut is placed on the flat surface in front of the plotter the computer sends cutting dimensions and designs for the plotter to produce a precisely carved design, and potentially repeat the cutting process on hundreds of objects, producing identical copies of the same design.