Page 114 - Mastering SolidWorks

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driVing SketcheS With Smart dimenSionS 83

Driving Sketches with Smart Dimensions
All dimensions in SolidWorks sketches can be created with a single tool, the Smart Dimension.
Dimensions are half of what you can use to drive changes in sketches with precision, the other
half being sketch relations.
The Smart Dimension tool can be used to create length, point to point, aligned, angular, radial,
diameter, arc length dimensions, and even reference (nondriving) dimensions.
By default, SolidWorks installs with a setting called Instant2D activated. Instant2D is rela-
tively new and has some advantages and disadvantages. One of the advantages is that it enables
you to drag dimensions by the handle as shown in Figure 3.25. One disadvantage is that it
disables the Modify box, shown in Figure 3.26.
Figure 3.25
dragging a dimension
with instant2d activated

SolidWorks sometimes forces you to use new functionality by activating it by default, instead
of allowing you to decide. This is done in order for you to quickly discover new functionality.
Then if you like the new functionality, you keep it; if not, you can turn it off. The downside can
be a bit of initial confusion. I think in the case of Instant2D, they should allow users to turn it on
if they want. The new setting adds ease-of-use at the expense of precision dimensions. If you
wanted to drag type precision, you wouldn’t have put a dimension on it. You can turn off
Instant2D by deselecting the Instant2D tool on the Sketch CommandManager tab. The rest of the
book will assume that this option is turned off.
When you place a dimension you just created, SolidWorks automatically puts you into the
Modify box, which enables you to edit the dimension in several ways. You can disable this option
by removing the check from the setting at Tools ➢ Options ➢ General ➢ Input Dimension Value.
With that setting off, when you place the dimension, it will not display the Modify box.
You can change Smart Dimension values in several ways using the Modify box, shown in
Figure 3.25. The most direct method is to key in a value such as 4.052. The software assumes
document units unless you key in something specific. You can also key in an expression, even
with mixed units, such as 8.5 mm/2+.125 or 25.4+.625 in. You can also key in negative dimen-
sions, which function the same as the Change Dimension Direction button in the Modify box.
To the right of the drop-down arrow is a pair of up and down spin arrows that enable you
to change the value in the Modify box by a set increment amount. You set the increment in