Transformation for parallel projection
Parallel projections is also termed as Orthographic projection, are projections into one of the coordinate planes as x = 0, y = 0 or z = 0. The ordinary transformation for parallel or orthographic projection into the xy-plane that is z=0 plane as:
P_{par,z} = x ' = x
y ' = y
z ' = 0
In matrix form it as:
Hence, if P(x,y,z) be any object point in space, then projected point P'(x'y'z') can be acquired as:
P'_{h} =P_{h}.P_{par,z}