Session 3.3
LAB: Unlocking the Power of Lookup Tables for All Disciplines
Synopsis:
You know your type catalogs, but do you know lookup tables? They are so powerful, that you shouldn’t ignore their potential in your content library. Join us as we learn the ins and outs of Lookup Tables for use in all discipline content libraries.
Learning Objectives:
1. Define the Structure of Lookup Tables and Build One from Scratch
2. Understand and Author Entry Level Formulas Referencing Imported Lookup Tables
3. Leverage Advanced Logic to Reference Multiple Lookup Tables in a Single Formula
4. Perform Family Testing for Expected Functionality
Body:
Many aspects of Revit project development are so well known that even the novice users can google, find detailed information about and implement generally understood best practices with little effort. In Revit Family creation, there are also many portions that are rather well explored and documented. General modeling controls, formulas, type catalogs… All fairly well used. However, there are some dark corners in the Revit Family creation space that are widely unknown. And, as powerful as lookup tables are their potential should not be ignored in content library creation.
Why is it that many advanced Revit users do not realize or understand the power of a well configured lookup table? This is due to a programmed limitation in Revit. For the longest time lookup tables were only available to MEP users. And lookup tables, at that time, were only able to be used when the family category was specific to the MEP disciplines. Out of the box, lookup tables are still only used by Revit MEP content. Default Revit Architecture and Revit Structure content do not leverage the functionality of lookup tables. Also, lookup tables are typically only used to drive instance parameters, again for MEP fittings. A special lookup table formula will read values from an embedded CSV file whenever the main value(s) is modified. This is beneficial when working with pipe, ductwork, conduit and cable tray as the sizes can change for an entire system, and the fitting instances must all know how to update sizes as the main linear object updates. Fortunately, recent versions of Revit have removed the discipline limitations, so lookup tables can be used for families of almost any category.
But what does this all mean for Architecture and Structure families? There are thousands of examples with families having multiple nested IF() statements to allow for multiple options. Sometimes those options are complex, multi value dependent and difficult to reverse engineer for future maintenance. Lookup Tables are going to enable us to simplify family formulas making future maintenance significantly easier, and family content respond significantly faster than otherwise possible using multiple nested IF() statements.
This session will focus on the authoring of a Lookup table from scratch, define its basic use in a family, and then quickly move on to advanced multiple lookup table logic. While some examples will be pulled from the out of the box content library, there will be examples of lookup table uses that have never been presented in any public forum, and are not available in any public library.