When complex objects are involved, three-view
drawings are often not sufficient to convey all the
necessary details. Special views are added to provide
additional information. The special views which may
be encountered are auxiliary and rotation views,
sections, phantom views, developments, and
a. Auxiliary Views. If a feature of an object is
in a plane which is not parallel to one of the drawing
planes, it will not appear in true size or shape in any
of the three normal views. The sloping surface of the
object in figure 1-15, for example, appears in both the
top and right side views but is foreshortened in both.
In this case, an auxiliary projection is added. The
auxiliary view is obtained by projecting lines to a
drawing plane which is parallel to the slanted face.
Figure 1-16. Auxiliary view arrangement.
The auxiliary view is normally placed alongside a
view which shows the true length of the edge of the
perpendicular to one of the normal orthographic
slanted surface as shown in figure 1-16. In this case,
drawing planes, or if there is not enough room in the
the auxiliary view is related to the front view. If the
normal position, the auxiliary view will be placed
feature to be covered in an auxiliary view is not in a
somewhere else on the drawing. In this case; the
plane Figure 1-16. Auxiliary view arrangement,
auxiliary view will usually be labeled as "view A" (or
B, C, etc) with an arrow pointing to the face.
Auxiliary views do not usually show the entire object
as seen from the auxiliary view angle; only the
surface parallel to the auxiliary drawing plane is
covered. Figure 1-17 shows an auxiliary view
compared with a right side view of the same object.
Note that the circles appear as ellipses in the right
side view, and the distances between centers are
foreshortened. The auxiliary view only shows the
slanted face of the object, the holes appear in true
shape, and the distances in true length.
Figure 1-17. Auxiliary and side views compared.
Figure 1-15. Auxiliary projection principle