Negative space is the the space in and around the objects you see. Negative spaces are important for 3 reasons:
1. Seeing negative space makes it easy to draw difficult views, especially foreshortened views. Negative space builds on the concept of edges in drawing as shared edges: if you draw the negative space around a foreshortened form, you will have inadvertently also drawn the form, and you will find that it is drawn correctly.
2. An emphasis on negative space strengthens and improves the unity of your composition.
3. Focusing on negative space causes the language mode of the brain to drop out, allowing access to the visual brain mode, which is suited to the task of drawing .