Voids in un-hosted families can be used to cut objects in projects in Revit 2012

I mentioned and demonstrated the use of this feature tonight.

A post on Revit's Wikihelp site shows a good example. See http://wikihelp.autodesk.com/index.php?title=Revit/enu/Community/Tips_%26_Tricks/Modeling/Cut_with_unattached_family_instance_voids

It also helpfully shows which categories can be cut.