This new feature in Revit allows the user to add dimensional parameters in the model environment, similar to the way you can when creating a family. Instead of using the usual lock or equality constraints you can now create project based adjustable parameters to control geometric values. Unlike project parameters, global parameters are not category specific but can be associated with an objects existing type or instance parameters.
You will find Global Parameters on the manage tab, as you’d expect next to shared and project parameters.
The dialogue box as shown below is quite similar to that the family types dialogue in the family editor. From here you can edit, create, delete and sort parameters using the buttons in the bottom left.
When creating the new parameter, one of the things you can choose is whether it will be a reporting parameter. These when used will pull the value from a dimension, which can then be added into a formula to calculate the result of another parameter. A non-reporting parameter on the other hand is used to drive information.
A basic use of Global Parameters, will be to control dimensions either directly or using basic equations. However, there will undoubtedly be more adventurous application as they can be associated with so many parameters across the different disciplines in Revit using formulas to control the outcome.
In the example above, I’m creating a parameter to control the height of reference planes used on an in-place family of dado trunking. This will allow the control of the trunking height based on different reference planes.
Once created it gets added into the chosen parameter group. From here it can be simply filled in or a formula can be used to calculate the value. In the screenshot below you can see there is a reporting parameter for Ceiling Height driving a simple formula for Ceiling-Curtain Grid height.
Back in the model, the necessary dimensions have been placed between the levels and the reference planes. When selected you will get an option on the ribbon to label dimensions, you can then select the required parameter from the list. The icon will now be visible, which indicates that the dimensions are linked to a Global Parameter.
Amending the parameter value will now update all of the reference planes as below.
The process is also shown in this video.
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