What is a Revit ʼParameterʼ?
Short Answer
A Revit parameter is a data field that controls or describes elements in Autodesk Revit, such as dimensions, materials, marks, or visibility behavior. The most common professional method is managing them through Project Parameters or family parameters in element properties. Limitation: not every parameter can drive every category or workflow.
What You Need to Know Before
Warning: Revit parameters can look similar but behave very differently depending on whether they are built-in, project, shared, or family parameters. A common failure is using the wrong parameter type, then discovering later it cannot be scheduled, tagged, or transferred into standards-based documentation.
How-to
Command: Project Parameters
Shortcut: None
Quick Steps:
- Go to the Manage tab on the Ribbon, then click Project Parameters in the Settings panel.
- Click Add, then choose whether to create a Project parameter or select a Shared parameter.
- Set the Discipline, Type of Parameter, and choose whether it applies to Instance or Type, then assign the target categories and confirm.
Variables & Settings
Key Setting: Instance vs Type
Expert Setting: This choice controls whether the parameter changes per individual element or across all elements of the same type. In practice, using Type when Instance is needed is a common source of wrong schedules and inconsistent model data.
Why it Fails
- Cause 1 (Geometry): The parameter is assigned to a category or family behavior that does not support the intended geometric control, such as expecting a text parameter to drive a dimension.
- Cause 2 (layers/Locks): The family or element may be constrained by locks, formulas, or nested family behavior, preventing the parameter from changing the model as expected.
- Cause 3 (Command/Logic): The wrong parameter class was used, such as a project parameter when a shared parameter was required for tagging, or a type parameter when instance-level control was needed.
Quick Fix & Best Practice
- Quick Fix: Open Project Parameters and verify the parameter is assigned to the correct categories, with the correct Instance/Type setting; if it must appear in tags, recreate it as a Shared Parameter.
- Manager’s Verdict: Use parameters early and with naming standards. For production projects, prefer shared parameters for data that must be scheduled, tagged, filtered, or exchanged across families and templates.
FAQ
Can a Revit parameter control geometry?
Yes, if it is created in a family and properly linked to dimensions, visibility, or formulas.
What is the difference between instance and type parameters?
Instance parameters vary per element; type parameters affect every element of that same type.
Do all Revit parameters appear in tags?
No, only supported built-in parameters and shared parameters are typically available for tagging.
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