Isometric drawing
Isometric projection is a common method of creating 3D object representations which can be directly measured. Parallel receding lines define the edges of all sides, and they are typically drawn at 30 degrees to the horizontal. To create or project artwork in isometric projection, click Isometric in the Perspective Document palette. Your artwork will appear slightly more realistic if you check Foreshortened, resulting in the foreshortening of isometric receding lines.

For extensive control and measurement of isometric objects, use Hot Door CADtools in Adobe Illustrator.