I know 7d2d uses some of these features. What I have learned from modding POI's, is they have .mesh files for almost everything. These mesh files are low poly copies of the actual, fully rendered objects or structures. As you get closer to them, you see everything change from low to high poly. And back again as you move away. It works fine when you're on the ground. But if you take to the air, it gets a bit clunky. You can reduce your FOV range to help counter the slow draw issue. But then you can't see as far.