Video: Use Global Parameters

Use Global Parameters to establish variable constraints in a project that can be controlled from a centralized location.

This video demonstrates the following:

1. Create a global parameter.
2. Assign a global parameter to a dimension.
3. Apply a global parameter to control an element's parameter value.

Note: This video was recorded using Revit 2017. When using a newer software release, you may notice differences in functionality and user interface.

Transcript

In a project file you can use global parameters to control the geometry of elements and build relationships between different elements in the project. You can also use formulas to create even more complex parametric relationships between the global parameters. ​

In this example the doors leading to the classrooms are constrained to the intersecting perpendicular wall. When the wall moves the doors move as well. To change this relationship from a static constraint to a variable constraint you can use a global parameter. ​

First, on the manage tab, click global parameters. In the global parameters dialog click to create a new parameter. In this case we will be using the parameter to control the inset of the door framing and the values are set. Specify a default value for the global parameter and click ok. ​

Now place a dimension, the dimensions will be used to apply the parameter to the geometric condition. Select the dimension and in the contextual tab click the label drop down to apply the global parameter. The door is repositioned using the value of the global parameter. The small pencil icon near the dimension indicates the value is controlled by a global parameter. You can delete the dimension, but the global parameter controlling it can remain by clicking ok in the warning box. ​

Apply the global parameter to the other doors in a similar way. To change the position of all of the doors, you simply change the value of the global parameter. ​

You can also use global parameters to directly control certain instance parameters in a family. For example, the ceiling element in this section constrained to the underside of the deck above in order to maintain a consistent plenum space. A reporting global parameter establishs the position of the ceiling relative to the 1st floor. ​

The ceiling height global parameter constrains the top of the clearstory window and a new global parameter uses a formula for the sill of the clearstory window. Now when the floor structure is altered the ceiling position and clearstory automatically adjust to maintain the minimum plenum space required. ​

By using global parameters to create relationships between elements in a model you can update and maintain the model geometry more easily.