Wire-Frame Models:

A wire-frame model of an object is the easiest, however more verbose, geometric model that might be used to represent it mathematically in the computer. This is sometimes referred to as an edge representation of the object or a stick figure. The word "wire-frame" is associated to the fact that one might image a wire i.e. bent to follow the object edges to produce the model. Normally, a wire-frame model consists totally of points, arcs, lines and circles, conics, and curves. For instance, a user might, with three dimensional (3-D) wire-frame models, enter 3-D vertices, say (x, y, z), and after that join the vertices to built a 3-D object. An instance of 3-D object & its wire-frame model are illustrated in Figure 1. Wire-frame modeling is the most usually utilized technique and is available for all commercial CAD/CAM systems. Wire-frame modeling is let a natural extension of traditional methods of drafting. As a result, it does not need extensive training of users; nor does it require the use of unusual terminology as surfaces and solids.

(a) Wire-frame Model; and (b) of a Part

Early wire-frame modeling method, developed in the year 1960s, was firmly two dimensional and it was designed to automate drafting and easy NC program verification. In those days, users need to construct the geometry of an object in the wished views independently because of the lack of centralized database systems. After that, in the early 1970s, the centralized database concept enabled modeling of three-dimensional objects like wire- frame models which might be subject to three-dimensional transformations. Creating geometry in one of view is automatically projected & displayed in other views. This increases user utilization by saving time and flexibility on manual design and drafting.