FBX (Game Engines)

FBX is a 3D scene exchange format that Autodesk bought in 2006 and turned into the common language between Maya, 3ds Max, MotionBuilder, Unity, Unreal Engine and Blender. It can carry geometry, materials, object hierarchy, cameras and animation; for urban development it is the geometry part that is used.

The export is for when a city has to end up inside an engine or a 3D package: a game level prototype based on a real district, a VR walk, an architectural visualization with genuine surroundings, an urban traffic simulation. Modeling a city block by hand takes longer than taking ready-made OpenStreetMap outlines.

Only buildings go into the scene. Every building outline is extruded to its own height: first the height tag is used, and if it is missing, building:levels multiplied by 3 meters; if that is missing too, a neutral default of about 9 meters is applied. Optionally a base is placed under the buildings; where elevation data (DEM) covers the area, buildings and base follow the terrain.

Coordinates are converted to meters relative to the center of the selected area, with the Y axis pointing up — which means the model lands in Unity and Unreal at the right scale and orientation. The file is a genuine binary FBX; if the build fails, the export honestly ends with an error instead of slipping you another format under an .fbx extension.