what is the function of a CAD system ?

Answer 1

CAD stands for either Computer Aided Design, or Computer Aided Drawing, and is a program that enables users to draw just about anything using their computers and a CAD program.
It can be used to produce floor plans of a building, or for drawing complex mechanical parts. It can produce drawings in either two dimensions, or three dimensions, and can even incorporate animation.
Normally, producing drawings using CAD takes longer than with a pencil and paper, but the big advantage of CAD is that once it's drawn, it can be emailed. Also, it very quick to modify a CAD drawing.

CAD is moving into the movie world as well. The film "Titanic" had a lot of sequences produced using CAD.

CAD programs can also be linked to computer aided machines, so that complex mechanical parts can be made. CAD programs also drive cutting machines, so that clothing can be made from a CAD program.

There's lots more that a CAD program can do, but I hope that this helps to explain some of its applications.

If there is anyting specific that you want to know, just post the question, and either I or someone else will try to givr you an answer.

Answer 2

A Computer Aided Design system lets one do drafting on a computer.

Often, layers allow the simulation of several transparent sheets which can be turned on or off. CAD can be 2D, or 3D.

A high-end CAD program may allow photo-realistic rendering of objects or structures which do not yet exist.

I once attended a seminar intended to relate how one could
get CAD-like results from MicroSoft Paint.