Blender and BTG

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Blender and BTG
Developed by Lauri Peltonen
Latest release Export: 31 Jan 2009
Import: 07 Mar 2011
Written in Python

With the use of a special import&export script, BTG files can be opened in, and exported from Blender. This makes it possible to edit FlightGear's terrain and specifically airports in a visual editor.

User documentation


Download the two scripts:

Place both files in your Blender's .blender/scripts/ directory. Common locations are:

  • Windows: C:/Program Files/Blender Foundation/Blender/.blender/scripts

Make sure to correct the $FG_ROOT setting in the import file, if needed. Default setting is:

FG_ROOT = "/usr/local/share/flightgear/"

Scripts should work with Blender 2.4x (latest available is Blender 2.49b), they will not work with version Blender 2.6x.



Import via File > Import > Simgear (.btg) v7.

Note: rename the [ICAO].btg.gz file of an airport, to its corresponding [tileid].btg.gz, in order to import it correctly. For importing KSFO, we need to rename KSFO.btg.gz to 942050.btg.gz, for example.


Export to a file with a .btg.gz extension, via File > Export > Simgear (.btg). Make sure to enter the correct coordinates and radius, as displayed in the console (you can copy&paste from that one) and/or screen on import.

Known issues

  • Textures are not applied automatically in Blender, altough they are loaded.
  • Imported meshes are shrinked because Blender does/did not support huge enough models (they are loaded correctly, but you cannot zoom out enough to see the whole tile).
  • Sometimes exported triangle has its texture coordinates in wrong order which leads to weird looking textures (e.g. on a runway).
  • After exporting .btg files, polygon are not smooth anymore. This will result in weird looking mountains.