Polyfaces mesh to solid

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…

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)