You can specify the units of measurement for global variables, and for the values and equations that define the global variables. You can define the units in the Equations and Modify dialog boxes for dimensions, and in PropertyManagers that support equations.
Assigning units of measure in equations ensures that you do not need to edit the equations if you change the unit of measure property of a document. It also allows you to create equations that mix values with different units of measurement.
For example, you can create a global variable Length and define it by the equation: =100in + 3mm + 5cm. The equation includes values with three different units of measurement. If the unit of measurement of the document is inches, then Length evaluates to 102.087in. If you change the unit of measurement of the document to millimeters, then Length automatically evaluates to the value of 2593mm. You do not need to edit the equation, or be concerned that the size of the part will change.
In the Equation and Modify dialog boxes, type-ahead lists help you assign a valid unit of measurement to each value in an equation.