That'd be good and the best way to learn. Perhaps, if it's accurate enough, the only thing I'd need to do with it is adjust the area around the runways, taxiways and ramp. Thank you. So, essentially, I'd have two scenarios... Starting on the ground at KILM, the FSX/P3D rendering engine will choose the higher LOD, guaranteed, so I'd have to set a higher LOD for my customized, small terrain CVX BGL (by choosing a higher LOD in MCX?) Flying into the area, FSX will, under circumstances (I can't say I understand what the circumstances are, yet), choose the BGL by which it encounters first and you can set small spots outside the edges of the larger area BGL by making tiny areas around it...like outside the corners and at mid-points of edges of a rectangle.