Types of Projection in Computer Graphics
When the centre of projection is situated at an infinite distance such that the projectors are parallel to each other, the type of projection is called Parallel Projection.
In Parallel Projection, image points are found at the intersection of the view plane with parallel projectors drawn from the object points in a fixed direction. The two basic types of parallel projection are:
Orthographic Projection occurs when the direction of projection is perpendicular in which the direction of projection isn’t parallel to any of the three principal axes.
When the angle between the projectors and the plane of projection isn’t equal to 90 then the projection is called oblique projection.
There are two types of oblique projection:
The direction of projection is so chosen that there is no foreshortening of lines perpendicular to the plane of projection.
The direction of projection is so chosen that the lines are perpendicular to the plane of projection are foreshortened by half their lengths.
A Perspective Projection of a 3D object, we transform points along projection lines which are not parallel to each other and coverage to meet at a finite point that is called Projection Reference Point or Center of Projection.