The Graphics of Two- dimensional Perspective
The transposing of visual foreshortening into graphic foreshortening returns to drafting techniques. The familiar perspective components are arranged as they would appear in a top and front view with frequent reference to a side view. The basic difference is that the front view becomes a perspective view.
The object or arrangement of objects are, of course, the essential element in the top view. It is a scaled drawing to maintain proportions within the forthcoming perspective and appears on the ground plane or plane of the paper. The top view of the cube in this example has been altered to add interest and to also create a greater difference between the top and side views of an otherwise simple form.
The picture plane, which in the top view will be a line, is placed in front of the object. The observation point is located slightly left of center and at a distance that will provide a cone of vision of 30' or less. The horizon line and ground- line will be drawn after a check with the side view.
The side of the object in this example is used primarily for height dimensions. For that reason it is located on the groundline or on the level of the object if it is not touching the ground. Although the horizon line is drawn in the front view, it is established in the side view at a height to best reveal the object. An extremely placed HL, too high or too low, will distort the perspective as much as a wide cone of vision. The horizon line in this example is placed above the object to more clearly illustrate the vanishing points. The distance between HL and GL is the height of HL in the front view.
The front view, or perspective of the object, is developed between OP and PP. In the example the drawing appears cramped, but in a wider arrangement of objects, such as those that might appear in a stage setting, OP would be at a greater distance from PP, allowing sufficient room for the development of the perspective view.