About Global Parameters

Use global parameters to drive or report values.

You can use global parameters in a project to:

drive the value of a dimension or constraint.
associate to an element instance or type property to drive its value.
associate to an instance or type project parameter.
report the value of a dimension, so this value can be used in equations of other global parameters.

Although there are many uses for global parameters, here are a couple of examples:

Non-adjacent equality - The use of equality dimensions to constrain a model is powerful, but you are limited to situations where the equal spaces are adjacent. With global parameters, you can assign the same value to multiple non-adjacent dimensions.
Set the position of one element by the size of another element - Element positioning based on the size of another element is possible by using the alignment and dimension locks, but the process can be simplified with global parameters. For example, placing beams beneath a floor can be difficult at times. When the beams are referenced to the same level as the floor, each beam needs to be offset by the thickness of the slab. Modifications to the floor require that you update each beam. With global parameters, this adjustment can be made automatically. Create a reporting dimension, and then set the beam's offset value to be driven by that reporting parameter. Now when the floor changes, the beams will automatically adjust.