166 Section 2 Drafting Techniques and Skills
Draw a Line
Through a
Point and Parallel to a
Given Line
CAD
Using a Triangle and T-Square
(Manual Procedure)
1. Line AB and Point P are given, Figure 6-5A.
A line parallel to Line AB is to be drawn
through Point P.
2. Position a T-square and a triangle so the
edge of the triangle lines up with Line AB.
3. Without moving the T-square, slide the
triangle until its edge is in line with Point P .
4. Without moving the T-square or the
triangle, draw Line CD through Point P.
This line is parallel to Line AB.
Using a Compass
(Manual Procedure)
1. Line EF and Point P are given, Figure 6-5B.
A line parallel to Line EF and passing
through Point P is to be drawn.
2. With Point P as the center, strike an arc
that intersects Line EF. This radius is
chosen arbitrarily. The intersection is
Point K. With the same radius and Point K
as the center, strike Arc PJ.
3. With the distance from Point P to Point J
as the radius and Point K as the center,
strike an arc to locate Point G. Point G is
Figure 6-5. Drawing parallel lines. A—Using a T-square
and triangle. B—A compass can also be used.
A B
C
A
B
D
P
P
F
J
K
E
G
Figure 6-6. Drawing a parallel line with the Parallel object snap. A—Line AB and Point C are given. B—Line CD
is drawn parallel by snapping to a point along Line AB and then establishing the parallel alignment path. Note that
the line can be drawn in either direction from Point C along the alignment path.
A B
Start
point
Alignment path
Parallel
line
Snap point
(Parallel snap)
Alignment path
(desired direction
for line)
Snap point
to establish
alignment path
the point where this arc and the first arc fi
drawn with Point P as the center intersect.
4. Draw Line GP. This line is parallel to EF.
Using the Parallel Object Snap
(CAD Procedure)
Parallel lines are normally drawn in CAD
with the
Offset
command. This command allows
t
you to select an existing line and copy it at a
specifi distance. The new line is parallel to the fied fi
existing line. If you want to draw a line parallel to
an existing line without specifying the distance
between lines, use the Parallel object snap with
the
Line
command. Use the following procedure.
1. Line AB and Point C are given, Figure 6-6A.
2. Enter the
Line
command and draw a
line that begins at Point C. To specify the
second point, use the Parallel object snap to
snap to a point along Line AB, Figure 6-6B.
After acquiring the point, use your cursor
to establish the parallel alignment path and
draw Line CD. Specify the second point for
Line CD by using direct distance entry or
picking a point on screen.