Graphics Programs Reference
In-Depth Information
A lot is happening behind the scenes as you apply parametric constraints.
You can get a great sense of how these constraints work at keeping your drawing
objects in order by trying the STRETCH command on objects after you apply a
constraint to them.
You can ind the iles I use in this sequence of steps at this topic's companion
The drawing named
afd19a.dwg
contains the unconstrained geometry, and
drawing
afd19b.dwg
contains the end product.
The following steps present a very simple example of dimensional constraints:
1. Start a new drawing and make the Ribbon's Parametric tab current.
Turn on some appropriate precision drawing aids on the status bar, such as Snap,
Ortho, and Osnap.
2. Draw some reasonably precise geometry using some of those precision tech-
niques I describe in earlier chapters.
In the following example, I've used the RECTANG and CIRCLE commands to draw
the geometry you see in Figure 19-2. The rectangle is 10 units square, and the
2.5-unit-radius circle is deliberately drawn away from the middle of the square.
3. On the Dimensional panel of the Parametric tab, click the top part of the
Linear split button.
A linear dimension icon appears beside the pickbox and AutoCAD prompts you to
specify the first constraint point or pick an object.
Just like the DIMLINEAR command, the Linear dimensional constraint tool is
infer-
ential
— which way you drag the crosshairs controls whether you get a horizontal
or vertical dimension. Also, just like DIMLINEAR, you can press Enter at the com-
mand prompt and select an object to dimension.
4. Press Enter at the command prompt to confirm you want to select an object and
then select the bottom horizontal line segment.
