After is applied, the corners of the frustum are transformed into the corners of a rectangular box, shown in Figure 3.19. The following performs a simple translation of the box along the axis and some rescaling so that it is centered at the origin and the coordinates of its corners are :

If the frustum is perfectly centered in the plane, then the first two components of the last column become 0. Finally, we define the canonical view transform from (3.41) as

Steven M LaValle 2020-01-06