with the right side parallel to the profile plane.
The block is then drawn, using all six views of
By careful examination of figure 5-22, you will
see that the lines AB, AE, BD and BC and the
surfaces ABC, ABE, and BDE are oblique to
three regular planes of projection. The lines are
foreshortened and the surfaces are not shown in
their true shape in any of the six normal
The first step in the drawing of any auxiliary
view is to draw the object in normal multi-view
projection, as shown in figure 5-23. A minimum
of two orthographic views is necessary. The space
between these views is generally greater than
normal. The reason for this will become apparent.
Notice in figure 5-23, in the front view, that A
is the end point of line AE (top view) and C is
the end point of CD.
The second step is to decide which line or
surface is to be shown in an auxiliary view and
which orthographic view it will be projected from.
The following facts must be considered when
rendering this decision:
1. Front or rear auxiliary views are always
projected from a side view.
2. Right or left auxiliary views are always
projected from a front view.
3. An elevation auxiliary view is always
projected from the top view.
The third step is to select the auxiliary and
reference planes. The auxiliary plane is simply a
plane parallel to the desired line or lines
representing an edge view of the desired surface.
In figure 5-24, the true length of line AB and the
true shape of surface ABE are desired. A left side
auxiliary view is needed. The auxiliary plane is
drawn parallel to line AB in the front view. Line
AB actually represents an edge view of surface
ABE. The reference plane (top view) represents
an edge view of the orthographic view (front view)
from which the auxiliary view will be projected.
Therefore, when front, rear, or side auxiliary
views are desired, the reference plane will always
be in the top view. When elevation auxiliary views
are drawn, the reference plane may be in any view
in which the top view is represented by a straight
line. The reference plane in figure 5-24 is the edge
of the top view that represents the front view.
Remember that, although these planes are
represented by lines, they are actually planes
running perpendicular to the views.
Step four is to project and locate the points
describing the desired line or surface. Draw
the projection lines from the orthographic
view perpendicular to the auxiliary plane.
Then take the distances from the reference plane,
whether by scaling or with a compass. The
distances are the perpendicular distances from
the reference plane to the desired point. In figure
5-24, the projection lines are drawn from points
A, B, and C in the front view, perpendicular to
the auxiliary plane. The projection line from
point A indicates the line on which point E
will also be located. The projection line from
point C designates the line of both C and D,
and that from B locates B only. To transfer
the appropriate distances, first, look for any
points lying on the reference plane. These
points will also lie on the auxiliary plane
where their projection lines intersect it (points A
and C). To locate points B, D, and E, measure
the perpendicular distances they are from the
reference plane in the top view and transfer
these distances along their respective projection
lines in the auxiliary view. The points are
equidistant from both the reference and auxiliary
planes. Therefore, any line parallel to the
reference plane is also parallel to the auxiliary
plane and equidistant from it.
The fifth step is to connect these points.
When the total auxiliary view is drawn, it is
sometimes hard to discern which lines should be
indicated as hidden lines. A rule to remember is
Those points and lines lying furthest away
from the auxiliary plane in the orthographic view
being projected from are always beneath any point
or line that is closer. In figure 5-24, point C
(representing line CD) in the front view is further
from the auxiliary plane than any line or surface
it will cross in the auxiliary view. Therefore, it
will appear as a hidden line.
The final step is to label and dimension the
auxiliary view. The labeling must include an
adequate description. The term AUXILIARY
must be included along with the location of the
view in relation to the normal orthographic views
(LEFT SIDE AUXILIARY VIEW, REAR
ELEVATION AUXILIARY VIEW, and so
forth). Dimensions are given only to those lines
appearing in their true length. In figure 5-24,
only lines AB, AE, and BE on the auxiliary view
should be dimensioned.