Orthographic Projections:

Orthographic projections are one of two projection types derived by subdivision of the parallel projection subclass. Additionally to being parallel, projectors in orthographic projection are also perpendicular to the view plane (Hearn & Baker, 1996). Orthographic projections are further categorised as either multi-view or axonometric projections, which are explained below.

Orthographic projections are the projections onto one of the coordinate planes, that is x = 0, y = 0 or z = 0. Matrix for projection on Z = 0.

Figure: Direction of Projectors for an Orthographic Projection

Transformation is to set the z coordinates of position vector to zero          

 For x = 0 & y = 0