I created a sample lookup table as follows:
In Revit, the parameters in the test family:
A text parameter is created in the family called 'Type Name'. The formula is broken down as follows:
Tells Revit it's a lookup command
- (Lookup Table,
Refers to the lookup table name in the 'Lookup Table' parameter
Usually there is a value between the quotation marks. This refers to which column to reference in the lookup table, but in this case we create a 'null' value. This is what allows this method to work
- "NOT SPECIFIED",
The text value that is used if there is no matching value in the lookup parameter
the lookup parameter value for the lookup formula to reference.
I'm not sure why this actually works, but I suspect that even though the syntax for the formula is correct for a lookup, the omission of a search column reference means it returns the first value it comes across, which is the 'Type Name' in the first column.
Hope this is useful.