Graphics : Computer Aided Design (CAD)

Computer Aided Design (CAD) packages are the most sophisticated computer graphics packages. They are used by architects to design buildings and engineers to design machinery. CAD packages operate in a very similar way to drawing packages. They store information about each object that makes up an image so that the image can be easily manipulated. A fully featured CAD package may cost several thousand pounds.

The most notable features that are present in a CAD package which are not present in a drawing package are :

3D Objects Objects and drawings can be created in three dimensions rather than just two. This is vital for producing plans of houses etc. Images can be viewed from any angle.
Accuracy Objects can be positioned much more accurately using a CAD package. Accuracy can easily be to within one thousandth of an inch.
Libraries of Components Libraries of frequently used objects, such as bolts or windows can be stored and reused in many designs.
Costing of Designs Using a database of object costs a CAD package can estimate the cost of producing a design that has been drawn.

Computer Aided Design programs can sometimes be connected directly to automatic machinery such as a lathe which is controlled by the computer. A design made on the program could then be manufactured automatically using the lathe. When a CAD program is used like this it is called Computer Assisted Manufacturing (or CAM).

GCSE ICT Companion 04 - (C) P Meakin 2004