Yes, I have played with the camera.clip_near and camera.clip_far options as well. Even when I am over the terrain in the valleys the terrain disappears when I tilt, pan or move it in another direction. It is very weird. Also note that the tiles are one sided planes as models. Sometimes, I can get the camera to show half of the terrain and not the other half. I think it has to do with some type of culling. I wonder if there is a way to turn this off.