oblique projections illustrate the general 3 dimensional shape of the object. However only faces of the object parallel to the plane of projection are shown at there true size and shape, that is angles and lengths are preserved for these faces only. In fact ,the oblique projection of these faces is equivalent to an orthographic front view.
TYPES OF OBLIQUE PROJECTIONS-
Cavalier Projection-A cavalier projection is obtained when the angle between oblique projectors and the plane of projection is 45 degree. In a cavalier projection the foreshortening factors for all three principal direction are equal. The resulting figure appears too thick. A cabinet projection is used to correct this deficiency.
Cabinet projection- An oblique projection for which the foreshortening factor for edges perpendicular to the plane of projection is one half is called a cabinet projection.