Figure 8-11.—Development of a truncated pyramid.
view D to the upper horizontal line on the front view
(point Y), and the other from X to the lower horizontal
line of the front view (point 2). Draw a line from the
apex through points Y and 2 in view D. The distance
between points Y and Z equals the true length of the
truncated pyramid With the compass point at the apex
of view E, find any convenient point to the right of the
orthographic view, scribe an arc with a radius equal to
the distance between the apex and point Y in view D,
and a second arc with a radius equal to the distance
between the apex and point Z in view D. The two arcs
are shown in view E. Draw a radial line beginning at
the apex and cutting across arcs Y and Z in view E. Step
off lengths along these arcs equal to the length of the
sides of the pyramid: MN for the inside arc and OP for
the outside arc (view E); the lengths MN and OP are
taken from the orthographic view in view D. Connect
the points along each arc with heavy lines (for example,
points MN along the inner arc and points OP along the
outer arc); Also use light lines to connect the apex with
points M and 0, and the apex with points N and P, and
so on, as shown in view F.
View G is the completed stretchout of a truncated
pyramid complete with bend lines, which are marked
(X).
PARALLEL-LINE DEVELOPMENT
Look at figure 8-12 as you read the following
material on parallel-line development.
8-8
