Architectural Drawings - Carpenter's and Builder's Math, Plans, and Specifications - page 260

The arrows AA indicate that the object is viewed in the direction of
point L (toward the smaller end of the object), and the arrows BB
(in the direction of R ) toward the larger end.
The Scale
Scale is the ratio between the actual size of the object and the size
that it will be drawn. The scale is usually expressed on a drawing as
full size, half size, quarter size, and so on, or it might be expressed
as 1 inch

1000 feet, or any
other proportion that might be necessary to use. The scale is printed
on the drawing.
On a full-size drawing, the object and drawing are of the same
size. When the drawing is marked half size, the object is twice the
size of the drawing. Thus, the drawing of an object is shown full size,
half size, and quarter size (see Figure 9-7). If the building's height is

= 1 foot, 1 inch = 100 feet, 1 inch =

D d

HALF SIZE
DRAWING

FULL SIZE
DRAWING

OBJECT

d'

QUARTER
SIZE
DRAWING

d"

Figure 9-7 A drawing of an object to different scales: full size,
half size, and quarter size.

represented by H and its diameter by D , then these dimensions
will be the same for the full-size drawing. That is, H = h ; D = d .

For the half-size drawing, h =

1

/ 2 H ; d

=

1

/ 2 D . Similarly, for the

quarter-size drawing, h =

/ 4 H ; d =

1 1

/ 4 D .