You can assign global parameters to element properties, such as family parameters, as well as to instance and type project parameters. 
Note: To better control the behavior of families that use system parameters, such as walls, doors, windows, columns, and electrical fixtures, a selection of system parameters are available to associate with global parameters. In the case of window and door families for example, the Sill Height and Head Height parameters are related; therefore only one of these parameters can be associated with a global parameter at a time.
- Select the element and locate the instance or type parameter. 
- Click the button to the right of the parameter and its value. 
  
 
  The Associate Global Parameter dialog opens. 
   Non-reporting global parameters that match both discipline and parameter type are available for selection. 
   
- (Optional) Click 
   (New Global Parameter) to create a compatible global parameter. (New Global Parameter) to create a compatible global parameter.
- Select a global parameter from the list to assign to the parameter. 
- Click OK. 
 
  Note: If you need to modify the value of a newly-created global parameter, click Manage tab 

 Settings panel
 
 
	 
 (Global Parameters).