In actual work, there is rarely an occasion when all six
principal views are needed on one drawing. All these views
are principal views. Each of the six views shows two of the
three dimensions of height, width and depth.
In general, when the glass box is opened, its six sides are
revolved outward so that they lie in the plane of the paper.
And each image plane is perpendicular to its adjacent image
plane and parallel to the image plane across from it. Before it
is revolved around its hinged fold line (reference line). A fold
line is the line of intersection between any hinged (adjacent)
image planes.
The left side, front, right side, and back are all elevation views.
Each is vertical. The top and bottom planes are in the
horizontal plane. But in most cases the top, front, and right
sides are required.
D. COMBINATION OF VIEWS
The most usual combination selected from the six possible
views consists of the top, front, and right side views some
times the left- side view helps to describe an object more
clearly then the light side view.
N.B: The side view of the front face of the object is adjacent to
the front view and the side view of a point will be at the
same distance from the front surface as its distance from
the front surface on the top view.