Forums >> Revit Building >> Technical Support >> String Values in Formulas

gaadmin

active

Joined: Fri, Apr 8, 2005
1 Posts
No Rating

I am familiar with programming but new to Revit. 

The short: Regarding formulas, are text parameter (string value) tests allowed in conditional statements?

The long: I have a room schedule and I have created a Calculated Value.  In the Formula field I am using a conditional IF to test the values of other parameters.  I would like to test the string value from one of the text parameters.  A simplified version is this:

IF (Occupancy = "Grade 3", Area/50, Area/40) 

With this however I get a message that says: "Improper use of boolean expressions".  If I use:

IF (Area > 600, Area/50, Area/40)

It works.  However the second formula is not the calculation I wish to make, I just used it to test that the issue was with the string expression.

Any help is appreciated!

This user is offline

TomDorner

active

Joined: Sun, Apr 25, 2004
1207 Posts

You cannot use text in formula evaluations.  If you are evaluting occupancy then you have to take a more sophiscated approach using Schedule Keys to develop a room or area style and then apply that Schedule Key to the room or area.

More in-depth than I can cover in a post.  There are some posts out on www.augi.com that do cover this in some detail.  I think a few that I have even contributed to.

-----------------------------------

Tom

www.reviteer.com   http://twitter.com/Reviteer

This user is offline

View Website

revolution9

active

Joined: Wed, May 16, 2007
3 Posts
No Rating

Further Question on these formulas...

I understand the formula when it relates to an integer and I am able to input the correct formula to create a check between occupancy, load factor, and exits etc.

However, I would like to apply the same type of check into my Room Finish schedule and check between the Wall, Ceiling, Base, and Floor Finishes in the Schedule VS the Room Finish Tag.

So, in short, I have created Shared Parameters called Wall Finish Tag, Ceiling Finish Tag... which are Text Parameters (since we simply enter in the text of each material/finish into the room properties).  I get the Boolean Expression error when I create the formula if(Wall Finish=Wall Finish Tag,1,0). Is this type of formula possible, or can it only work with Integers/Area etc?

Any suggestions on how to make this kind of check work?!

Thank you!!

This user is offline

WWHub

site moderator|||

Joined: Tue, May 16, 2006
13079 Posts

As Tom stated many years ago: " You cannot use text in formula evaluations."  Still can't use text in conditional statements. 

This user is offline

revolution9

active

Joined: Wed, May 16, 2007
3 Posts
No Rating

Fair enough. Is there any way to create the right type of parameter that will allow this check?

What if they were Material/Finish types? I REALLY want this to work!

This user is offline

WWHub

site moderator|||

Joined: Tue, May 16, 2006
13079 Posts

Sure, don't use text, use numbers!   

That doesn't work for you, does it?  Revit does a lot but it doesn't do everything everybody wants. 

You will need to check this manually as you always did in CAD or use the other tools provided by Revit.  Export your schedule to a txt file, open that with excel and put your formula there.  <<< DON'T COME BACK AND SAY YOU WANT IT IN REVIT BECAUSE YOU CAN'T

This user is offline

revolution9

active

Joined: Wed, May 16, 2007
3 Posts
No Rating

Hahahaha well it was worth a shot!

I suppose the best way to show this is keep the parameters as text, and keep the 'Tag' parameters in the schedule to compare. I was hoping to provide conditional formatting, but I understand that this is impossible.

thanks for the help. I really appreciate it!

This user is offline

dingohot

active

Joined: Mon, Mar 15, 2010
199 Posts

Here is a workaround I use.

http://plevit1.blogspot.kr/2013/12/text-string-value-in-formula.html

-----------------------------------

want more?

You can get more tips at Enjoy Revit

This user is offline

View Website

Parameter formulas losing calculated values

1

Current date in formula on titleblock

0

Understanding Formulas

14

Creating Dimensions with english and metric dimesnions on one string

5

Preloaded Size Values in Revit MEP

3