Revit 2017 - Calculated Values in Tags

This addition permits us to do the same thing to tags that we've been using in schedules. For example, in a tag I'd like to show the difference between the client required area and the actual area of a room. That wasn't possible without some export/import or Dynamo shenanigans. Now it is possible, right in a tag.

This starts in the Edit Label dialog via a new button, then it is the same as the dialog we've seen in Schedules.

Since these can be used in schedules and tags, and it has to be done separately for each use, it probably makes sense to document all of the formulas we use so they are easily harvested for another project. Build them into a template and there is less need to do that at all. Regardless it wouldn't hurt to have a Drafting View set aside with the text versions of all the formulas we use stored there. That way a simple Copy/Paste operation can harvest a formula to use in a tag or a schedule or both.

Percentage of Gross

In a database environment we can create a query that asks questions of data stored in tables or other queries. In this Revit is a little different. We can ask questions (queries) of tables (element categories) all day long but we can't ask questions of the answers to previous questions...or in database terms a query of a query.

There is one example in Revit that is already wired to permit such a result, a percentage of another value, such as Room Area. In this example I've made a little tiny project, created a schedule and added a calculated value to the schedule. This is the final result of the schedule.


This is the properties of the calculated value.



Any parameter's data type, based on what you include in the schedule, and tell Revit to Calculate Totals will be an option for consideration with "Percentage" selected. For example these are my choices if I also include Perimeter and Volume in the schedule.

Wish - Calculated Values in Tags

This is a common wish. We want to be able to DISPLAY calculated values not only in schedules but also in tags. Right now lacking this feature makes me feel like this guy!



Thanks to this site for the image.

Amended 09/11/08 - Per the comment, note that I'm asking to DISPLAY a calculated value in a tag. I'm not telling anyone how to accomplish it. I'm asking to be able to use a tag family to report a value that is the result of a calculation in a project relative to any element.

Dept. of Unfair - Calculated Values

There exists an inequity in Revit feature distribution among the versions when creating Calculated Values.

In Revit Architecture 2009 it looks like this:


In Revit Structure 2009 it looks like this: (same as RAC)


In Revit MEP 2009 it looks like this: (the unfair bit)


In RME they have added a button, which opens a secondary dialog, to aid in the choosing of parameters which eliminates typing mistakes. You choose a parameter > click OK or double click to select the parameter. It does not filter for appropriate parameters however which means you could try to use the Name parameter in your calculation, which probably wouldn't work very well.

The RAC and RST version of the dialog also have a TAB sequence problem (very subtle mind you). That is that when you use the TAB key to advance from field to field Revit advances from Type to OK instead of Formula, the next parameter below. The actual sequence is this: Name > Formula/Percentage > Discipline > Type > OK > Cancel > Help > then back to Formula.

Interesting that the RME TAB sequence is fixed too! Yet another outrageously unfair situation! I hereby lobby for the fair and equal distribution of new dialog box features among other things (like embedded schedules and conditional formatting!!

Yesterday I was building to a crescendo of surprise and elation by demonstrating the calculated parameter technique the old "hard" way when an overly aggressive student stole my thunder by announcing "But Steve I just clicked on this little button with the three dots and it let me pick the parameter instead"...rats! foiled again. Maybe next time...