Create cut and fill earth excavation geometry from Revit topography


I have been trying so hard to model in Revit the volume of excavations, cut and fill, starting from a topography with building pads using only Dynamo.

I duplicated a clean topography before applying building pads on it, created subregions and regenerated the trimmed toposurface to be able to create solids and boolean operations of trim, difference, intersection.

For example here you see the topography excavated on bottom and the topography trimmed for excavation on top of it, whith opened faces, the intention is to get a watertight 3d solid of all of it.

The workflow is so hard in memory consumption and time running, that I am looking for easier or smother possibilities, avoiding to export to a modeling software and importing back to Revit.