Please help write this formula

[arkyletecture694360]

I literally have a mental block when it comes to comprehending formulas. So if anyone could help me get this figured out, it would be much appreciated.

I've got a multi-window family I have created to make ganged or mulled windows. The two key parameters are "Window Quantity" and "Mull Width" and the nested Windows and Mulls are created via an array.

My main problem right now is that I have a stand alone (non-array) center mull for when the Window Quantity = 2. For any Window Quantity greater than 2, it is not visible. I also have a Mull Width control parameter that prevents the mulls from being 0", but if the Mull Width is set to 0", then the mulls are not visible.

So... I think what I need the Yes/No parameter to say for the Center Mull visibility is this:
Visible when Window Quantity = 2 and Mull Width > 0"

So, how do I make that work with a formula? Or, am I way off here? (Everything works perfectly with the window except for that so I think I am pretty close!)

[CAtDiva]

I haven't done a lot of formulas myself, but this thread might help: http://www.revitforum.org/tutorials-tips-tricks/1046-revit-formulas-everyday-usage.html.

[arkyletecture694360]

Thanks, I've checked that out. I need to see a formula work to fully grasp it. I can't use hypotheticals like that to figure out how they will work for me (at least with the harder ones anyway).

These If/And formulas are tough!

[Revitaoist]

You need that goofy boolean operator for the yes/no checkboxes. Something like: if(Window Quantity=2, 1>0, 0>1) Revit reads the 1>0 as "true" and 0>1 as "false". So it would read my example as if 2 widows, check yes, if not, uncheck.