ABSTRACT
Projection is used to map a high-dimensional object to a lower-dimensional view. Projection can be of two types: parallel and perspective. In parallel projection, projection lines are parallel to each other while in perspective projection, projection lines appear to converge to a reference point. Parallel projection can again be of two types: orthographic and oblique. In parallel orthographic projection, the projection lines are perpendicular to the view plane, while in parallel oblique projection, the projection lines can be oriented at any arbitrary angle to the view plane. Usually for 3D projection, parallel orthographic projection can also be subdivided into two types: multi-view and axonometric. In multi-view projection, the projection occurs on the primary planes i.e. XY-plane, YZ-plane, or XZ-plane, while in axonometric projection, the projection occurs on any arbitrary plane. This chapter discusses the concepts behind the various types of projection and derives the projection matrix in each case. These are then illustrated using examples, MATLAB codes and graphical plots for visualization.
