Topography to mass with Dynamo



I am trying to do a tunnel in Revit, so I want to cut some topography. Since Revit can not cut topography with a building I remind to use Dynamo.

In Dynamo I want to select the topography, thicken it so it becomes a solid and then use the “difference” node to subtract my building.

Is it possible? I can not thicken the topography… :confused:

Thanks in advance!!terreno Dynamo