Autodesk Revit Architecture

[#1]

Hi,
I'm using revit from few times and I don't know all the possibility to model all 3d forms. Particulary, I have big problems to model 2 intersected caverns: I tried to model them with rhinoceros or other 3d software and then import the model into revit, but this cause some problems with the export to autocad (problems of visualization). I prefer modelling the intersected cavern directly into revit. Is it possibile?How?
Thanks in advance.

[#2]

A cavern? That word is not in my architectural dictionary.   Do you mean the vaults at the lower level of the building?