How to set Family Type parameter to “None”

While I was creating a simple furniture object with nested families, I wanted to control the visibility or availability of one or both of the nested families – in this case the hanging bars.

The most obvious solution would be using a Yes/No parameter that is linked to the Visible parameter of the single objects, like in illustration below.

This doesn’t sound logical: first choose a family type for the front bar that refers to one of my nesting families, loaded in the main family, and then switching it off using “Bar Front Visible”, no? Maybe it’s that small “programmer’s” part of my mind that doesn’t like this solution. In fact I would like to see a choice in my dropdown list that says “None”. Something like this maybe?

How did I get the “None” entry in the list? Well, just make a copy of your other nested family and delete all geometry (or at least make it invisible). Load the dummy “None” family into your main family, and you’re done.

Although, be aware when using this solution. As many things in Revit, it works when you keep in mind next rules:

• When you align the nested family in the main family, make sure you use the named reference planes (Left, Top, Back, …) of your nested family.
• In the “None” family, only delete the solid geometries, but not the reference planes, certainly not the named ones like Left, Top, … (see rule above).
• When parameters from your nested family are linked into your main family (i.e. Materials), than be sure this parameter is also available in your “None” family, even if it’s not consumed by any geometry. Otherwise the link will break.

It’s quite a simple and silly looking solution, but I hope you enjoy it 🙂

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