Hi , I'm fairly new to this development stage so please enlighten me. I want to know how can I add the earth curvature to a 3d city for use in p3d v4.5. So here's exactly what's happening now. I have a model of a city which is quite large area. It doesn't have a ground poly as I used fsearth tile software to make the ground and it remains as a separated bgl file. So when I place this 3d city model in p3d , buildings close to the edges are floating above the ground. I suspect this is because I didn't correct geometry for the earth curvature. So I found this " fsx earth curvature " option in mcx and I used absolute altitude in meters and gave the correct coordinates. When I apply that all the buildings in the city model moves to the pivot point of the city model. So what exactly am I doing wrong gentlemen ?Any help would be greatly appreciate.