The of moving all the tiles near the origin before rendering them is to try to reduce floating point round off problems. When rendering, it is straightforward to calculate the proper view point and up vector so that the scenery will appear right side up when it is rendered. 2.4 Scenery file format Here is a very brief overview of the flight gear scenery file format. Some of this format will have to change in the future, so I won't put a lot of effort here right now. This description will be most understandable if you reference an actual scenery tile file.
Units are in meters.
I will eventually need to add texture coordinate support to this file format, as well as a way to reference and position objects from an external library. This section is very fluid right now. I have implemented a first pass at generating scenery. This was a good learning experience, but it exposed several flaws and limitations in my original approach. I am in the midst of a complete overhaul of these tools which is intended to address all the short comings of my first attempt.