Returns the perspective projection. The Frustum, which is given by (right, top, near) (left, top, near), ( right, bottom, near) and (left, bottom, near) as surface area and (right, top, far), (left, top, far), ( right, bottom, far) and (left, bottom, far) as cover area. This furstum will bee thransformed to a cube with (1, 1, 1) and (-1, -1, -1)
Returns the ortogonal projection, where the point( right, top, far) is mapped to (1, 1, 1) and the point( left, bottom, near) to (-1, -1, -1) You can imagine a cube, which is genereted by it's edgepoints ( right, top, far) and ( left, bottom, near) Remark: The viewingcube is clipping the scene