A point can be considered physically real and can be located
by a small dot or a small cross. It is normally identified by two
or more projections. In fig below, points A and B are located
on all three-reference planes. Notice that the unfolding of the
three planes forms a two-dimensional surface with the fold
lines remaining. The fold lines are labeled as shown to
indicate that F represents the Front view, T represents the
Top views, and S represents the Profile or Right side view.
The planes are replaced with reference lines HF and FP,
which are placed in the same position as the fold lines.
7.2. Reference Planes
Unfolding of the reference planes forms a two-dimensional
surface, which a drafter uses to construct and solve problems.
The planes are labeled so that T represents the top or
horizontal reference plane, F represents the front or vertical
reference plane, S or P represents the side (end) or profile
reference plane. Thus a point 1 on the part, line or plane
would be identified as 1F on the top reference plane, and 1T
on the top reference plane, and 1S on the profile reference
plane. The folding lines shown on the box are required to as
reference lines on the drawing. Other reference planes
(auxiliary planes) and reference lines (auxiliary lines) are
drawn and labeled as required.