Formula to change a width depending on a visibility parameter

[Kev_D]

Hey all

This could get confusing, so I will try my best to explain in detail.

I am creating a double door family that has a centre mullion. The centre mullion is controlled by a visibility parameter and comes out flush to the front of the door which in turn separates the doors. If this mullion is turned off, I want the doors to meet. 

Each door panel is a nested family and both can have different widths assigned. The door frame width parameter is determined by the door frame thickness, and both door panel widths. So when family is loaded into project, only the door panel width should be changed.

If I did not have a centre mullion, the door frame width would be simple and set at '(Door Frame Thickness * 2) + (Door Panel Width 1 + Door Panel Width 2)'. When I introduce the centre mullion, the formula would change to '(Door Frame Thickness * 3) + (Door Panel Width 1 + Door Panel Width 2)', but obviously I can not have 2 different formulas for one parameter.

Is there a way I can do an IF formula for this. Something along the lines of this; if (centre mullion = ON, (Door Frame Thickness * 3) + (Door Panel Width 1 + Door Panel Width 2), (Door Frame Thickness * 2) + (Door Panel Width 1 + Door Panel Width 2)).

I know this formula is wrong, but I hope someone understands what I am trying to achieve. I can't find what to type for ON in the centre mullion part of the formula.

Would appreciate any help.

Revit Architecture 2016

[Alfredo_Medina]

Like this:

jf (centre mullion,
then do this,
otherwise do that)

[Alfredo_Medina · Accepted solution]

In my previous message, first line, it should be "if", of course. I see that I wrote "jf".

"centre mullion" is a yes/no parameter. Therefore there is no need to say "= on" ". Simply say: if(centre mullion,

[Kev_D]

Thank you Thank you Thank you.

My head was wrecked trying to find what equals the Centre Mullion. Did not know that you just right the yes/no parameter.