Graphics Programs Reference
In-Depth Information
Finally, the AutoConstrain tab (Figure 16.18) gives you control over the behavior of the
AutoConstrain command. You can control the priority of the constraints applied to a set of
objects as well as which geometric constraints are allowed.
FIGURE 16.18
The AutoConstrain
tab of the Con-
straint Settings
dialog box
Putting Constraints to Use
So far, you've seen some very simple applications of the parametric tools available in AutoCAD.
While the parametric tools may seem simple, you can build some fairly elaborate parametric
models using the geometric and dimensional constraints you've learned about here.
Besides having a drawing of a part that adjusts itself to changes in dimensional constraints,
you can create assemblies that will allow you to study linkages and motion. For example, you
can create a model of a piston and crankshaft from a gas engine and have the piston and crank-
shaft move together.
In the next exercise, you'll look at a drawing that has been set up to show just how con-
straints can be used to mimic the way a mechanical part behaves:
1.
Open the piston.dwg file, which can be obtained from the companion website.
2.
Click the arc in the right side of the drawing (Figure 16.19).
FIGURE 16.19
The piston
drawing in
motion
Click the arc to select it.
Click the center grip, right-click, and select Rotate.
Rotate the arc and watch how the drawing changes.
