X3D (Extensible 3D)

X3D is the ISO standard for three-dimensional scenes, the direct heir of VRML but written in XML. Thanks to that the file is read by any parser, edited as text and embedded into a web page through X3DOM or X_ITE without plugins.

The export is taken for demonstrative tasks: an interactive model of a district on a department website, an appendix to a paper, teaching material, exchanging geometry with scientific software. This is the most "document-like" of the three-dimensional formats — it is put into a paper's archive and opened years later.

The file holds an X3D scene of version 3.3, Interchange profile: buildings are extruded from outlines into volume (LOD1, flat roofs), each is assigned a material colored by type of development, and a light source and a viewpoint are added. Very small outlines with an area under half a square meter are discarded as noise.

Height is taken from the height tag, otherwise from the number of floors at 3 meters each, otherwise from a typical height for that type of development, and as a last resort — 9 meters. The 3D export area is limited to 1500 km²: beyond that the scene turns into millions of polygons that no viewer will open.