204 Exploring Drafting
When a drawing is made with the aid of
instruments, it is called a mechanical drawing.
Straight lines are made with a T-square,
triangle, or drafting machine straightedge.
Circles, arcs, and irregular curves are drawn
with a compass, French curve, or the appro-
priate template for the object needed.
As discussed in Chapter 7, drawings are
also generated with computer-aided drafting
(CAD) software. While many drafting firms fi
now use CAD for developing drawing projects,
knowledge of manual drafting techniques
and procedures is still extremely valuable in
solving design problems.
Regardless of the technique, whether
traditional (manual) or CAD drafting, the
principles of drafting remain the same. The
drafter must be familiar with the standards
and procedures necessary to develop draw-
ings that accurately describe objects.
Many drawings used by industry are
created as multiview drawings. A multiview
drawing is a drawing that requires more
than one two-dimensional view in order to
provide an accurate shape and size descrip-
tion of the object being produced. In devel-
oping the needed views, the object is normally
viewed from six basic directions, as shown in
Figure 9-1. These are the six principal views.
They include the front, top, right side, left
side, rear, and bottom views. See Figure 9-2.
Left
view
Top view
Rear view
Right
view
Bottom
view
Front
view
Figure 9-1 An object is normally viewed from six
basic directions.
Top view
Bottom view
Front view Right view Left view Rear view
Figure 9-2 The six basic directions of sight provide the principal views for developing a multiview drawing.
Shown are the principal views of the object in Figure 9-1.