Import Complex Rhino Topography/Polysurfaces to Revit

Hi All,

I have previously imported Rhino 5 files successfully into Revit but am having trouble with a topography file supplied to me for a project.

Can anyone suggest ways of simplifying the polysurface topography (without losing too much detail) so that I can import the .3dm file into revit without it crashing? I have attached the file for reference.