Page 315 - Mastering SolidWorks

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PAtterning in A Sketch 287

In this example, I created a sketch pattern of 4 × 4 rectangles and used the Fully Define Sketch
tool to add dimensions. Then I copied and pasted the sketch and removed all the dimensions and
relations. Figure 9.2 shows the Feature Statistic results.
Fully defined sketches are best practice, but it is not due to rebuild speed. Sketch relations are
costly from a rebuild-time point of view. Patterning sketch relations are even more costly. The
rebuild time does not even come close to the time that it takes the Fully Define Sketch tool to
create all the dimensions and relations in the first place. This combination of geometry, software,
and hardware took about 30 seconds of CPU time to add the relations and dimensions.
For most models that have fewer than 50 features, you may never notice this rebuild time, and
the price you pay is certainly worth the peace of mind you get from having the stability of a fully
defined sketch. For large models where you have hundreds of features, or features that use lots
of very busy sketches, you should pay attention to how much information you put into the
sketch and try to limit sketch patterns and even elements such as sketch fillets, using feature
fillets instead where possible.

Patterning a Sketch
Sketch patterns are an available tool—they are valid, and in a few cases, they are truly necessary.
It is best to preselect the sketch entities that you want to pattern before using the Sketch Pattern
tool. If you do not preselect, then after the PropertyManager is open, you can only select entities
to pattern one by one, because the window select is not available for this function. The RMB
selection options, such as Select Chain, are also not available in this interface, reinforcing the
need to treat sketch patterns as a preselection feature.

TIP When creating a linear sketch pattern, be sure to select the Add Spacing dimension check boxes.
if these dimensions are not added, then editing the pattern becomes more difficult.

Using the Linear Sketch Pattern
The Linear Pattern PropertyManager is shown in Figure 9.3.
Unlike other PropertyManagers, the selected entities for the sketch pattern functions are
found at the bottom of the PropertyManager instead of at the top. This is a little confusing.
Sketch tool PropertyManagers, such as Convert Entities and Mirror, place the selection box
at the top.
The Direction 1 panel works predictably by establishing the direction and spacing and then
the number. The Angle setting enables you to specify a direction that does not rely on anything
outside of the sketch.
The Direction 2 panel works a little differently. You must first specify how many instances
you want, and then the other information will become available. The spacing is grayed out
until you tell it you want more than one instance in Direction 2.