BGL is the file format used by Microsoft Flight Simulator to store scenery. It uses the .bgl file extension. BGL stands for BAO Graphical Language. Where BAO stands for Bruce Artwick Organisation, the original creator of the Flight Simulator series.
There are a lot of different 'types' of BGL file, each with their own structure, each containing different things, but all with the *.bgl extension.
These include: Terrain (Created using Resample)
- Mesh: A 3D surface representing terrain onto which textures and models are placed.
- Aerial Imagery: An aerial photo converted for use in Flightsim.
- Landclass: A low resolution raster where each pixel represents and type of landcover (i.e. farmland, bush) and which, in turn, loads the relevant texture to 'paint' the mesh.
- Waterclass: A low resolution raster where each pixel represents and type of water (I.e. Tropical, muddy) and which, in turn, loads the relevant texture to alter the colour of the water.
- Population Density: A raster where each pixel represents the number of people living in the area.
Airport Information (Created using BGLComp)
- Compiled Runway, taxiway, apron information etc (XML)
- Placed Buildings and objects (*.mdl + XML)
Other Scenery objects
- Custom buildings made with Gmax (*.mdl + XML)
- Library buildings placed in a new position.