Null

In Revit, null means that a parameter has no value assigned — it’s empty, blank, or uninitialized. This applies to all parameter types: strings, numbers, booleans, etc. For example, a Manufacturer parameter left blank in a generic component is considered null.

Null values are important to detect because they often indicate missing data. A parameter might be null if it hasn't been filled in yet, if the element doesn't support it, or if it’s a shared parameter that hasn’t been applied to all relevant families.

In rule-based validation, checking for null helps ensure that critical fields aren’t forgotten — like Fire Rating, Cost Code, or Room Name. If a value is required, “null” is a red flag.

✅ Validator: Null: Should Be Null

Description: Passes only if the value is not set (i.e. null or empty).

🔧 Revit Example:

• Parameter: Manufacturer of a Generic Model Family
• Rule: Manufacturer = null

📌 Use Case:

Ensures that placeholder or generic components don’t include manufacturer-specific data, which might mislead during early design phases or violate procurement neutrality.

✅ Validator: Null: Should Not Be Null

Description: Passes only if the value is set (i.e. not null or empty).

🔧 Revit Example:

• Parameter: Fire Rating of a Door Type
• Rule: Fire Rating ≠ null

📌 Use Case:

Ensures that all fire-rated doors have a defined fire resistance value, which is essential for code compliance, documentation, and coordination with fire protection plans.