Hi reported this problem shortly after starting with VW2011 I was provided with a fix by the techies and OzCad which was a Cinema 4D QT agent to replace existing one it works but a QT VR object in 2010 would be 10-15 MB in 2011 it is 700MB + so I export back to 2010 to make the VR object if required.
I can provide you with the fix if you send me an email
(It seems that it occurs especially when Vectorworks and Cinema 4D are used together.)
If that is the case would unticking the prefs (Allow option-click in-place duplication) help
I think if you give it a go you'll find it gives you exactly what you want I created a quick easily checked roof and it gave me the correct answers just try it
when I try to open the file with QT 7 it tells me it is not a movie file and it is 0 kb, when instigating the export it does it in 5 seconds one render and finished, is there some new setting somewhere?
the export Quicktime VR object menu item is still there but it exports nothing, I can export the file to 2010 and I can export it from there but, if the VR object was scrapped why is the menu still there?
in VW 2011 you can actually use combine connect tool to connect the two roof faces if you go that way, otherwise create a roof from polygon click on the handles where you want the gable (against the wall) and select gable 0 overhang and deselect create gable walls in OIP