Polyfaces mesh to solid

HI
I have imported buildings from placemaker revit and converted this file into stl format. My ultimate intention is to get a solid buildings and terrain so that i can export it to simcentre star ccm+ and run cfd simualtion for evaluating pressure coefficient in the buildings facades. Is it possible to convert polyfaces mesh to solid in Rhino 7.
Thank you

Hi -

Reverse engineering a mesh to a NURBS object can be anything from very simple to extremely complex. Rhino 7 has tools to make this somewhat easier in the more complex cases - see Reverse Engineering [McNeel Wiki]

That said, the requirements aren’t completely clear to me.

Often, CFD simulations will be run on meshes…
-wim

HI
my intention is to convert polyfaces surfaces of the buildings and terrain in the stl file attached to solid for CFD simualtion in simcentre star ccm+.modified downtow scaled.stl (3.3 MB)