If Then Else

Tests conditions on the element and writes one value or another. Fire resistance for the structure, a status from a checkbox, a flag on everything that breaks a rule.

Steps

1. Categories — which elements: tick the categories, and add a filter if only some of them should take part.
2. If — the condition to check: one or more conditions, each a parameter (any parameter), a comparison and a value. With more than one, choose All conditions are met or Any condition is met. Add conditions with +.
3. Then — what to do when the condition is true: the target parameter and either Write a value or Leave unchanged.
4. Else — what to do when the condition is false: the same choice.

Text comparisons: is equal to, contains, begins with, ends with, their negations, is empty, is not empty. Number comparisons: equal to, not equal to, greater than, greater than or equal, less than, less than or equal.

Example

Good to know

• Text comparisons ignore upper and lower case.
• A number comparison can carry a unit: < 2 m works on a length shown in millimeters. The value read from the element must be a number by the same rule as in Calculated Value; 1.OG is text, and a number comparison on text is never true.
• Yes/No parameters compare alike in an English and a German Revit.
• <clear> as a value empties the target — see Empty values.

Works with

• Parameters: any parameter of the element — shared, project, family or built-in — typed by name, or a built-in one picked from the list; see Which parameters an operation can use.
• Smart tags: in the Then and Else values — see Smart tags.
• Only if empty: tick it for this operation in the Executor's list before a run, and it writes only where the target is still empty.
• Preview: type sample values and see what the operation writes, before Revit — see Preview and Example.
• Filter, Active view, Selection: like every operation — see the filter and Whole model, Active view, Selection.

Used in: Conditional values.

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