For those who need realsitic environment for X-plane simulation (eg all buildings ) there is an 'easy' way well not so easy for some area, for europe and france almost all building are now in the openstreet map file but for most other area you need to insert your own.
here a video over Copenhagen https://www.youtube.com/watch?feature=player_embedded&v=3ZUq5Ti47Ys
What you need :
- X-plane 9 or 10
- Open Street map file for the area of interrest ( http://www.openstreetmap.org/ you can export only a small area with the web based version no more than 5000 nodes, for bigger area go to http://planet.osm.org/ )
- An editor like JOSM ( http://josm.openstreetmap.de/ ) this one can overlay bing aerial photo so you can add your own buildings based on the photos, can be a long work !.
- Open Scenary X for the objects and textures ( http://www.opensceneryx.com/ ) just install and run it
- OSM2XP to convert your OSM file to Xplane ( http://osm2xp.com/ ) this software generate the compatible scneray for xplane and you can customize the rendering like type of forest, buidling, 3d objects, ...,
When done just copy the generted directory to your ustom scenary and enjoy