168 Exploring Drafting
Erasing Objects
The Erase command provides a quick
way to remove unwanted objects from a
drawing. After you select the objects to erase,
the command automatically removes them
from the drawing. The Undo command can
be used to restore an object that has been
erased unintentionally.
Arraying Objects
An array of objects can be created by
orienting multiple copies of a selected object
in a pattern. This operation is useful when the
same object appears in multiple locations in a
regular pattern in the drawing (for example,
when a pattern of holes is machined in a round
part). Arrays may be created in rectangular or
polar arrangements with the Array command.
See Figure 7-16. A rectangular array is created
by entering the base point, number of rows,
number of columns, and the spacing between
rows and columns. The number of columns
and rows determines the number of objects in
the array. A polar array is created by speci-
fying a center point, the number of objects in
the array, and an angular value determining
the amount of rotation. Entering 360° creates a
full rotation of objects about the center point.
Mirroring Objects
When drawing symmetrical objects, it is
sometimes useful to create a mirror image.
This operation allows you to select an object
and make a mirror copy. This can save time
when you want to draw half of an object and
complete it by “mirroring” it. See Figure 7-17.
The Mirror command is used to mirror an
object. To use this command, the objects to
be mirrored are fi rst selected. Then, a mirror
axis is specified. The axis represents a line
about which the objects are “reflected.” The fl
command sequence typically allows you to
keep or delete the original objects selected
before mirroring.
Creating Rounded and Angled
Corners
Rounded and angled corners are often
drawn in mechanical drafting. A round is an
arc representing an outside rounded corner. A
Original
object
A
Original object
B
Figure 7-16 Arrays are created by orienting
copies of original objects in a regular pattern.
A—Rectangular array. B—Polar array.
Original objects Objects after mirroring
(0,0)
Figure 7-17 Mirroring an object creates a mirror
copy about a mirror axis. In this example, the original
image is mirrored twice using the X and Y axes.