conditional instructions in formulas

[monica.lena]

Bye to all,
I would like to create a family of beams that cannot have length greater than 3 meters.
the behavior I would like to have is therefore that when I go to insert this beam into the project, if I pull a line greater than three meters, the beam stops first.
I tried to use conditional formulas but revit gives me error, tells me that the reference plans are too bound.
place below an image to make you better understand the operation I entered.

 

[Tristan]

set in that way cannot work. you have two parameters that tie the same planes but one goes from 0 to infinite, the other cannot go beyond 3 m. to who has to give revit reason? because it gives you a mistake.. .

 

[monica.lena]

if I use only the length parameter if(length<300, length,3000) it gives me error saying that a circular chain of references was established, so I had inserted the parameter lm.
However, I fear that I have not tied them properly.
Can you tell me where I'm wrong?

 

[Tristan]

I'm afraid what you want to do is not possible if you don't cheat and create a "find beam" with a different family. Why do you want to limit the length to 3 m?

 

[monica.lena]

I would like to apply this bond to a beam that constructively does not have more than three meters. It is an element that is often repeated in this project and in future ones, in order to avoid errors I would have therefore wanted to set this limit to it.
What kind of 'alternative' family do you recommend?
Consider that it must be cmq an element that appears to me in the abachi.

Thank you.

 

[Tristan]

You could try starting with a generic line-based model and then "convert" it into a structural frame, but I can't tell you if it works. You have to try. . .