Depth and structure are the two qualities (visible traits or characteristics) of form.
Capture these two qualities in your illustrations while avoiding details. Draw details as the need
a. Depth is the most difficult of the three dimensions to capture and is an illusion in a
drawing. The use of perspective drawing is one way to help create this illusion. The illusion
created is distance. No one step of the systematic approach creates depth. It is achieved through
the entire process (fig 2-7). The following paragraphs give a brief introduction to perspective
Figure 2-7. An example showing depth