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Exploring Drafting
and dimensions. The way in which a part is
constrained controls how it will behave when
edited. For example, it may be necessary to
edit a part in order to create a slightly different
part. Identifying how the part geometry will
change when edited helps determine which
constraints to apply and helps the designer
anticipate how to make future edits in the
most effi cient manner. Dimensions should
also be planned to refl ect the design intent. In
some cases, it may be appropriate to constrain
dimensional values using equations. An
and helps determine how the part will fi t with
other parts. In addition, the origin of the
sketch should be planned at a location that
facilitates assembly with other parts. Referring
to the sketch of the drawer knob shown in
Figure 7-29, the top plane is used for the sketch
plane of the base feature, as the top view shows
the most basic profi le. The origin is located at
the midpoint of the horizontal line along the
base, which is suffi cient for this part.
Other important design factors to consider
include the application of geometric constraints
A
C
B
Goodheart-Willcox Publisher
Figure 7-31. Creating additional features to complete the drawer knob. A—A sketch is made on the bottom surface
to create the hole cutout. B—The part after using the sketch to create the hole cutout. C—A rendering of the
completed drawer knob after adding two locating pins.
Copyright Goodheart-Willcox Co., Inc.