Floor below grade

[mthurnauer]

I know that I had seen a thread on this a long time ago and my search could not locate it.
I have a large portion of a building that is underneath a plaza. I would like to try and model the plaza using the topo tools, but I am not sure how to "cut out" my below grade building from the topography. Is this possible?

[patricks]

http://forums.augi.com/showthread.php?t=36848

Post #7 and 8 seem to have the best method, where you put the topo above the subterranean building in a separate file with different poche base setting, and link it back in.