Inspection and Quality Control:

a. Program creation for inspection machines.

b. Comparison of produced parts along design.

Based upon the needs of the user and the capability of CAD system, a geometric model builds a product in one of 2-D, 2½-D and 3-D type models. A 2-D model defines a plane figure that is with length, breadth and '0' (zero) thickness.

A 2½-D model defines a component with breadth, length but steady thickness.

A 3-D model defines any generalized part shape along breadth, length and thickness as well.

Modern CAD systems represent objects in 3-D. Therefore, the designer might construct 3-D model of objects easily and store up the database of the model in the computer.

Geometric models can be classified into three types :

                                                         i.      Wire-frame model.

                                                         ii.      Surface model.

                                                         iii.      Solid model.