Parametric sketch relations are not the only way to drive dimensions with intelligence. You can also use equations, link values, and global variables. Equations help you create simple or complex mathematical relations between dimensions. Link values are essentially a quick way of making two dimensions equal. Global variables can be used in equations like other dimension names. These three techniques are all very similar and related to one another in the interface, but are used in different ways in different situations.
Equations can cause problems if used incorrectly, and have functionality that may appear incorrect at times, but if you are familiar with how the tools work, you can avoid the common pitfalls and get maximum benefit by adding intelligence to your designs.
Figure 9.1. The Equations interface
Using the Equations interface, you can turn off equations temporarily by deselecting the Active check box in front of the equation. Equations can also be deactivated by a design table. I will discuss design tables in more detail in Chapter 10, which discusses configurations. ...