86 Chapter 5
shortened to provide a more realistic view of the object. To foreshorten the side views, the object’s side
measurements are normally halved. In this case, the sides are 50 mm (2 inches) long, but they have
been drawn at 25 mm (1 inch). Because the oblique drawing is not realistic, it is rarely used by profes-
sional architects and engineers.
5.5 AUXILIARY VIEWS.
Occasionally we find surfaces or features on drawings that are oblique to the principal planes of projec-
tion and still are shown in their true shape. Other features in modern construction are also designed at
various angles to the principal planes of projection. To show these features or surfaces in true shape for
accurate description, auxiliary views are used. Auxiliary views are appropriate to obtain a true size view;
similar techniques to standard views unfolding about an axis are used. Auxiliary views are usually par-
tial views and show only the inclined surface of an object. In Figure 5.14 the true size and shape of the
object are shown in the auxiliary views of the angular surface. An auxiliary view is similar to an ortho-
graphic view except that it is projected to a plane parallel to the auxiliary surface and not to the custom-
ary orthographic planes. It is thus drawn at an angle to best view an object but not one of the primary or-
Figure 5.12 Technique for producing an oblique drawing. The front view is shown in its true form on the
horizontal line and should be drawn flat.