Revit Parameters

I had a client email me about Parameters. They were having a tough time getting their head around the different types, so I thought I would make a quick post about it.

In Revit there are four kinds of Parameters:

System Parameters
Shared Parameters
Project Parameters
Family Parameters

System Parameters which include the two you highlighted are built-in to Revit and cannot be changed, but they are always available. This means they show in tags, schedules, projects, families, etc. Project Parameters are custom parameters you add to a project. When adding a project parameter, it is available to all objects of the specified category throughout the project and CAN appear in schedules but NOT tags. You create them with the command on the Manage tab of the ribbon. Family parameters are only available to the Family in which they are added. They do NOT show in tags or schedules nor to other Families of the same category. However, you can make a custom parameter (Project or Family) available to tags and schedules by making them a Shared Parameter. Shared Parameters are defined in an external text file (a Shared Parameter file) and you can access them also on the Manage tab. It is VERY important that you have a single shared parameter file for the entire firm to “share” thus the name. You do NOT want more than one Shared Parameter file. All this file is used for is to define the parameter. Once defined, it knows how to behave. So ALL shared parameters will be created from this single source file. The end users will not need to have access to, nor do they need to even know about the Shared Parameter file. Kind of like a recipe for your favorite cookies. You need the recipe to get the cookies right, but you don’t need the recipe to enjoy eating them.

If you think there is any chance that a custom parameter will want to be scheduled or tagged, you should make it a shared parameter. So on your titleblock, you need to make those custom parameters at LEAST a project parameter. This will tell Revit what to do with them. But consider making them Shared for additional flexibility down the road.

Kind of Parameter	Who Creates it	Where does it live	Appear in Tags	Appear in Schedules	Description
System Parameters	Built in	Project and Family	Yes	Yes	Built-in to Revit, You cannot change it
Shared Parameters	User Defined	Project and Family	Yes	Yes	Custom Parameter created for the highest portability and flexibility
Project Parameters	User Defined	Project	No	Yes	Custom Parameter accessible to all objects in a Project
Family Parameters	User Defined	Family	No	No	Custom Parameter accessible only to the Family

Hope that helps to clarify things a bit.

Thanks

paulaubin