Geometry Surface Area

Hello all

It’s an old problem in revit, which is calculating the waterproofing area for the structure model substructure. Can Dynamo do the following, take the model, cut it at the specified site level, get the surface area of the foundation, tie beams, columns, walls that fall beneath the site level, export them separately for horizontal, and vertical areas.

A workaround in revit I know is to use the paint tool, but it is time consuming.

Ideas ?