A much underutilised parameter type is the Family Type. This allows you to assign different Family Types in you parameters, especially when using nested families.
This Parameter Type will allow you to have more control over the nested families in your project file, instead of having to go down the path of using additional parameters and complicated formulas.
The example below shows how these can be used in Revit Families.
I have a Generic Model Family called ‘Box’, which is a simple box extrusion that contains 2 types which vary in length.
This is controlled by a Type parameter called ‘Length’.
This is the Family that is going to be nested into another Generic Model Family called ‘Test’.
The New Family is setup and the ‘Box’ family is loaded in.
If I create 2 Types in this family called Test A and Test B, where Test A uses Box A and Test B uses Box B, all that I need to do is create a parameter that uses the Family Type.
The correct Category needs to be selected, in this case it is Generic Models.
This new parameter ‘Box Type’ controls the Family Type of the nested family (Box).
The Family types Test A and Test B, can now individually have a different Box assigned to them.
The final step in this process is to associate the ‘Box’ family with this newly created parameter. If you select the box family, in the options bar you can assign a Label to the Family, (just like a dimensional parameter).
The newly created ‘Box Type’ Parameter can be selected and you now have control over your nested family.
These parameters can be taken a lot further for use in dimensions, visibility control, materials, etc…..
So the next time you want to control nested families, the Family Type Parameter may be what you are after.