Lookup tables are used for pipe and conduit families to define parameter values in an external comma-separated values (CSV) file.
Lookup tables contain type data, allowing you to specify multiple part sizes without creating a separate family type for each size. Revit provides a size_lookup function that reads the necessary values from an external CSV file.
Data from lookup tables is stored within the family and uses the size_lookup function. Lookup tables are used in conjunction with type catalogs.
The syntax for the size_lookup function uses the following format:
result=size_lookup(LookupTableName, LookupColumn, DefaultIfNotFound, LookupValue1, LookupValue2, ..., LookupValueN)
| Where... | Is the... |
|---|---|
| result | returned value. |
| LookupTableName | name of the CSV file to lookup. |
| LookupColumn | name of the column from which the result value is to be returned. |
| DefaultIfNotFound | value that will be returned if LookupValue is not found. |
| LookupValue(1-N) | value to find in the first, second, and subsequent columns of the table. (When looking up values, the first column is skipped.) |
For example:
Notes:
- The size_lookup function provides the ability to look up numerical and text values.
- The size_lookup function is intended for instance parameters. If you want to use tabular data to define types with unique values for each type, create a type catalog.
Lookup table location
The location of lookup table files is defined with the LookupTableLocation parameter in the Revit.ini file. See
Directories Settings in Revit.ini.
Note: The User Profile version of the Revit.ini file is located in this folder:
%APPDATA%\Autodesk\Revit\Autodesk Revit 2023 Release. The UserDataCache folder contains default copies of files that are used to populate the user's profile, including Revit.ini. When
Revit starts for the first time for a new user, it receives a copy of Revit.ini from the UserDataCache folder. Thereafter,
Revit uses information from the User Profile version of the Revit.ini file.
Important: When you upgrade a model from a release of
Revit prior to
Revit 2014, you must copy the associated CSV files from the Lookup Tables folder of the older release of
Revit into the corresponding subfolder of the Lookup Tables folder for the release of
Revit that you are upgrading to. Alternatively, you can set the location of the Lookup Tables folder in Revit.ini to the pre-Revit 2014 location.