Three Point Perspective
In most situations, one- or two-point perspective is appropriate, but when a more extreme view from very low or very high is desired, three-point perspective is used.
In two-point perspective, all vertical edges are truly parallel to each other. Horizontal receding edges converge at one of two points on the horizon. In three-point perspective, the vertical edges are drawn to a vanishing point above or below the horizon. In three-point perspective there are no truly parallel lines in your drawing.
If you want to give viewers the impression of looking down on your subject, place the horizon line high on the page or even off the page. Establish vanishing points at left and right on the horizon line; the farther apart they are, the farther from the subject we appear to be standing. The edges of all surfaces (planes) parallel to the ground will converge at one of these two vanishing points. The edges of all vertical surfaces will converge at a third vanishing point placed well below the horizon.
To give viewers the impression of looking up at your subject, place the horizon and its two vanishing points low on the page and the third vanishing point well above the horizon. The edges of vertical planes converge at the vanishing point above the horizon, while the edges of horizontal planes converge at one of the two vanishing points on the horizon.
Three-point perspective is used when you want to give the impression of looking up at a subject from a low place or down at it from a high place.