Help with scheduling nested windows

[anorsworthy]

I've scoured the internet searching for a solution to this problem, but so far I haven't been successful. The problem I'm having is with a nested window family I created. In the hosting family environment the head heights of the individual units are accurate. When I upload the hosting family (with nested windows) into a project I see the whole assembly is scheduling head height properly, however the individual units are scheduling some strange values. They look right in the project, but the reporting values are off. For example, if I place a 6' high window assembly at a head height of 8'-0", the assembly shows a proper head height in the schedule, however each individual unit schedules their head heights at 4'-6". Any idea what's going on?

The hosting family is attached if you'd like to try it out.

[L.Maas]

What you want is not easy (impossible?) to achieve. The main issue is that Sill Height is a system parameter. It will be automatically created by Revit when you make a window. As these are special parameters it means that naming a family parameter in your family named "Sill Height" does not refer to the same thing.

When you nest your window (Nested_Single_30x72.rfa) into your other window family (Hosting window.rfa) automatically a "Sill Height" parameter is added. You can see this when selecting your nested family in the hosted window family. In this case your family has two "Sill Height" parameters (one you created, the other created by revit). The "Sill Height" parameter created by Revit can be changed so that your window will move up or down. As soon as you place your hosted window in a project a "Sill Height" parameter is added to this hosted window family. When you modify this value the hosted family will move up. However the nested window will not update its sill height accordingly.

If you need to have 'proper' head/sill heights of your nested windows you would need to create shared family parameters (e.g. window elevation) to both the families with some formulas and not use the "Sill Height" parameters (i.e. all kept at 0) created by Revit.

That you see strange values for your Sill Height for your nested windows in the schedule is because the Ref Level of your nested window is set at 3' 6".

Maybe some other users have a better approach. I would be interested to hear them too.

[anorsworthy]

Thanks so much for that detailed explaination! I'll try using shared parameters to drive/report the head height, but the reference level at 3'6" was a desperate attempt to compensate for the offset in project and actually has no effect on where the nested window is placed in the hosting family or the project environment; just forgot to change it back before posting 

[anorsworthy · Accepted solution]

That was it! I just needed to create a new shared parameter and now I have accurate head heights reporting in the schedule; a great timesaver for a project with over 60 winodws. Thanks so much for the help!

[MMAsterpasqua]

I realize I am about a year and a half late to the party here but I am having this same issue. I finally figured out Mulled Windows and now have a Head/Sill height problem.

If you add this new shared parameter and stop scheduling the OOTB Sill and Head Height parameters, do you have to manually enter all the values in the families in order to schedule them correctly? I.E. I have to work back and forth between the project and the families, finding and entering the sill height into the new shared parameter.