Friday, January 20, 2012

Parameter Pecking Order or Priority

There is no preference applied to one over another. A Shared Parameter is no different than a Project Parameter... a parameter is a parameter. How they are defined and shared between projects and families is different.

A family parameter is confined to the family. It can be seen and altered from within a project but not scheduled or tagged unless it is a built in parameter (created by Autodesk's Revit team) like those listed under the Identity group.

A Project Parameter is part of a project and applied broadly to a single category or even categories of families so that it can be scheduled, but not tagged.

A shared parameter bridges both, acting as a dictionary (the shared parameter file) by storing common definitions so they can be reused (yes "shared") in other projects or families. When you add a family or project parameter using a shared parameter (definition from the dictionary) it is really just another parameter but it has expanded possibilities because it is "shared".

If you add a family parameter to a door called "My Parameter" and add another Project Parameter to your project called "My Parameter" (applied to door category) and create a Shared Parameter (added to door and project) called "My Parameter" you'll end up with four (4) parameters called "My Parameter" in the project. All will be listed in the properties of the door family in the project. A couple will be listed in the door family itself when open in the family editor. A couple will be available in the Schedule Properties dialog. The name we "see" for a parameter isn't really what makes it unique. They have a GUID (globally unique Identifier).

Short answer...doesn't matter how you add the parameter, Revit doesn't pay more attention to one over another or deal with one kind first, then pecking order.

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