How is the Terrain modified ? If its imported with hills, how is it converted to flat?
thanmks
Did you import the terrain using Add Location from within Sketchup?
Then you could add more context and select Flat Site.
If you received or downloaded the terrain from a third party?
Maybe you could try the free extention “Eneroth Flatten to Plane”, or search for altenatives on the Extention Warehouse.
Hope this helps 