Revit formula with multiple conditions - How to write

[Jessicas]

HI,

I have a family i'm creating and there's a nested item that needs to be visible under certain circumstances.

Its a U-Shaped family, the sides are visibly controlled by yes/no parameters

There's a centre support that needs to be visible if the length gets to 8' or above.

So this is what I the conditions need to be...

Centre support visible if Length_Main > 7'11"

but if the Left side is visible the necessary length would be 7'11 + 1'4"

if the Right side is visible length would also be 7'11 + 1'4"

if Both sides are visible length would be 7'11" + 2'8"

does anyone know how this would be written. I'm definitely not good with writing the formulas.

Thanks in advance if anyone can show me how the formula would look.

[ToanDN]

Please share the family file.

[Alfredo_Medina]

You need to build a formula that checks for those things in order, from left to right, like this:

• first, check if Left is visible and Right is not.
• If that is true, do this,
• if not
• check if Right is visible and Left is not,
• if that is true, do this,
• if not,
• check if both Left and Right are visible
• if that is true, do this,
• if not,
• use a default or base length.

That sequence, translated to a formula, is like this:

[ToanDN]

My shot at it.  See if I am missing any conditions.

[Jessicas]

Sorry I was able to post this right at the end of my work day. 

[Jessicas]

Can anyone help with this? I've tried quite a few times to get something but i always get errors.

[ToanDN]

Have you tried the formula provided by @Alfredo_Medina and the other one by myself?

[Jessicas]

I tried Alfredo's it seems more towards what i think i need. I tried so many things with it and couldnt get anything to work. 

Yours.... honestly i have to idea whats going on 😮 really truely i suck at formula stuff

I attached the family in an earlier reply maybe it will help if people see the actual family set up.

[ToanDN]

We use different approaches to reach the same goal.  @Alfredo_Medina created one complex formula that does it all where as I decided to break it apart.  I showed screenshots of multiple conditions so you could see how the formula works.  It's up to you which one you select.

[Jessicas]

ok. Well I've had to move on so once I get back to that family I'll try your version out and see if i can get it to work.

[ToanDN · Accepted solution]

Here is my attempt at your family.  Obviously my brain is not as good as @Alfredo_Medina so I needed to add a few more parameters in order to make it work.  His original proposal should work if you can digest it.