In the 2D system, we use only two coordinates X and Y but in 3D, an extra coordinate Z is added. 3D graphics techniques and their application are fundamental to the entertainment, games, and computer-aided design industries. It is a continuing area of research in scientific visualization. Furthermore, 3D graphics components are now orthographic projection tutorial pdf part of almost every personal computer and, although traditionally intended for graphics-intensive software such as games, they are increasingly being used by other applications.
Parallel projection discards z-coordinate and parallel lines from each vertex on the object are extended until they intersect the view plane. In parallel projection, we specify a direction of projection instead of center of projection.