SUBDIVIDING LINE SEGMENTS
In principle, it is always advisable to work from the larger
part to the smaller. The successive repetition of short
lengths or measurements can often result in an accum
ulation of minute errors. It is therefore advantageous
to be ableto subdivide anoverall length into anumber of
equal parts. Being able to subdivide any given length in
this manner is useful for constructing the risers an runs
d
of astairway, as well as for establishing the coursing of
such construction as atiled floor or masonry wall.
• To subd ivide a line segment AB into anumber of equal
parts, draw a line at aconven ient angle b
etween 10° and
45° through the starting point. Using an angle t hat is
too acute wou ld make it difficult to ascertain the exact
point of intersection.
• Along this line, use an appropriate scale to mark off
the desired number of equal divisions.
• Connect the end points Band C.
• Draw lines parallel to BC totransfer the scaled
divisions to line AB.
Digital Drawing
This and many other drafting t echniques are programmed
into drawing and CAD software. Th process of working
e
from the general to t he specific, fromthe larger whole to
the smaller pa rts, however, remains the same.
20 I ARCH ITECTURAL GRAPHICS