Application of h/d
Figure 1 shows a house with a place located in front consisting of 9 blue squares. The square ABDC has a size ratio of v/w = 0.2. Assuming an eye-level position 1.5 m over ground, and AB = 1.5 m, all measure of the objects of the image are defined : The center of the place in front of the house is located 8.25 m from the Stand Point (SP) , its size is 9 x 9 m, the front of the house is situated about 20 from the Stand Point (SP) away.
Pre-allocating an - even imaginary - square allows to created a frame-work to properly locate all the objects involved reflecting correct proportions.
Figure 2a : Illustrates the creation of a "square" with a ratio of “visual” heights v to “visual” length w v/w = 0.2 (blue-rose) using a triangle with one angle of 90 and two angles of 45 degree.
Drawing of the lines p and q allow to create VP and the Horizontal Line HL.
Figure 2b presents square with v/w = 0.1.