Edge View of a Plane
An edge view of a plane is seen in a view where the line of
sight is parallel to the plane. The line of sight is parallel to the
plane when it is parallel to a true length line that lies on the
plane. Since a projection plane is always perpendicular to the
line of sight, it follows that a view drawn perpendicular to a
plane (perpendicular to a true length line that lies in the plane)
shows the plane as an edge. This can be seen in a vertical
plane, which appears, as an edge in the horizontal view, since
it is perpendicular to the horizontal projection plane. A
horizontal plane is perpendicular to the frontal and profile
projection planes and thus appears as an edge in these two
views.
When the given plane is oblique, an auxiliary (secondary
projection plane) plane is needed. In order to establish a line
of sight parallel to the plane, a true length line needs to be
drawn which lies on the plane. An auxiliary view where the
line appears as a point view shows the plane as an edge. So
the following are the genera steps that are required to create
an edge view. In figure below, plane 1-2-3 is given and an
edge view is required.
Step 1: Draw line 1H-2H on plane 1H-2H-3H, parallel to the H/F,
and complete the frontal view by projection. Line 1F-(^4) F is true length.