Revit Shaft Openings

I was reminded by a user request today of a feature I added to the Grasshopper IFC plugin to generate shaft openings in Revit.

Note this is one of the few areas where IFC doesn't really define an equivalent to Revit, where an opening can cut any object that intersects it's location.  So the IFC this generates is not compliant with the schema, and won't be recognized by any other IFC software other than my revit importer.

Here's a sample file and image to demonstrate the use of it.