Jan 19, 2012
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 five kinds of Parameters:
Global Parameters (New in 2017)
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.
*Update for 2017 – Had a comment below about Global Parameters (GP). So I added them to the table. Global parameters work in a project environment. They can be assigned to drive the values of instance and type parameters of elements in the project. So if you flex the global parameter, it can potentially impact several objects or types across the project. They are user-defined, but can be pre-built in your office standard template (RTE) files if you want. They can only be assigned to properties that are “exposed” by the factory. So certain things cannot yet be driven by GP. Most dimensions can also be labeled directly in a project environment with GP as well. This allows you to build relationships across the project to elements that are not necessarily physically next to one another.
|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|
|Global Parameters||User Defined||Project||No||No||Custom Parameter that can drive exposed instance and type parameters in the project|
|Family Parameters||User Defined||Family||No||No||Custom Parameter accessible only to the Family|
Hope that helps to clarify things a bit.