Formula-driven Family Type parameter.

[Anonymous]

In my Family I have a parameter of type <Family Type>. I want it to be controlled by a formula. I have problems with defining this formula. For the simplest example i just copy the whole name of family and the type and paste to the formula field. I receive an error (see picture below). What is the correct way of typing type names into the formula field?

[Sahay_R]

The highlighted item in the screenshot is what really needs to be in the formula. Watch out for cases and typos!

[Anonymous]

Thank you for your reply, but could you please be more specific about the syntax? I was trying different Options (for example Abtropfbrett Typ<IPN_Abtropfbrett : 300 mm> but nothing works.

[Sahay_R]

Parameters are all in the extreme left column. From your screenshot, it appears that the formula includes information from the middle column. If I am incorrect, then a clearer screenshot with the error message moved away from the dialog box would be appreciated.

Here's how parameters are organized in the dialog box- 

1) Left column = Parameter

2) Middle column = Parameter Value

3) Right column = formula, if any

The Formula is made out of Parameters, which will come from the left column.

[Anonymous]

You're right. In the formula field I tried the simplest possible way of assigning Parameter value using a formula. If the Parameter type would be let's say Integer, then if in formula field I would type "500", the Parameter Value would be set to 500. Apparently Family Type Parameters require different Syntax of formulas which is unknown to me.

[Sahay_R]

What exactly is it that you want your formula to do?

[Anonymous]

I want the parameter value equal IPN_Abtropfbrett : 300 mm if the value of Lenght is over 300 and  IPN_Abtropfbrett : 600 mm otherwise.

Normally it would be something like if(Lenght>300,"IPN_Abtropfbrett : 300 mm","IPN_Abtropfbrett : 600 mm")

[Alfredo_Medina · Accepted solution]

Family Type parameters cannot be set to a formula in a simple way. You need more parameters, one Family Type parameter for each variation, and one integer parameter to define which variation.

There is an example of this technique in "Exercise # 6" of this article that I posted in Linkedin:

https://www.linkedin.com/pulse/repetitions-randomness-revit-part-2-alfredo-medina/

[Alfredo_Medina]

Hello,  @Anonymous

Just curious, what was the end of this case? 

[Grigor_Panosyan]

The way you suggested in exercise 6 doesn't seem to work, I have tried to recreate the Hexagon family exactly as it is displayed in the Type Properties, but all I get is "The following parameter is not valid" after inserting the formula. I want to find out the right way of connecting Integer and Family Type parameters via a formula, but, unfortunately, I have no luck doing it. 

[Peter.Banski]

Thank You Alfredo,

Your Link is the one and only solution in the whole WWW that I found, how to steer "Family Type Parameter" with a Formula.

And it works very well!

Peter

[Alfredo_Medina]

---

@Grigor_Panosyan wrote:

"The way you suggested in exercise 6 doesn't seem to work, ..."

_________________________________________________

Please try again. It does work.

[Grigor_Panosyan]

Dear @Alfredo_Medina,  it does work like a charm, indeed I was doing something wrong back when I posted my reply.

Integer x Double Family Type x "if" statement became one of my favorite technics 

[Roberto.CabanasEPSPH]

Great!!! Brilliant explanation and technique.

[jquarry]

Is this still the best (and only) way to drive Family Type Parameters in formulas?

Now that it is 2022 I figured I might save someone some time doing any additional searching...

[Alfredo_Medina]

Hello, @Peter.Banski and all of you participating in this thread. I want to add that I have made a video about this topic, how to control family types by formula, plus another topic, how to apply random values to those family types. If you're interested, please follow this link:

https://www.youtube.com/watch?v=_8Md-Vrw8PU

[adriansin_randalllamb]

Adding to @Alfredo_Medina  's solution. The formulas also work with Yes/No checkboxes. Yes/No checkboxes can be more intuitive for users. Thank you so much for the solution.

[Rafael_Lucki1]

don't use this type family parameter, use visibility parameter to turn of other familys nested on you main because it does work better to write formulas