USD/USDZ (Universal Scene Description)

USD (Universal Scene Description) is a system for describing three-dimensional scenes that Pixar built for its own production and opened up in 2016. Today it is the backbone exchange format in film and in production: Houdini, Maya, Blender, Unreal and NVIDIA Omniverse read USD natively, and Apple built its AR format USDZ on top of it.

A map is exported to USD when the city is needed as a scene: a backdrop for a shot, an environment for visualizing a project, the context of a block in Omniverse. Instead of modeling city blocks by hand you get real development in the right proportions from a single export.

The output is a text .usda file: the Z axis points up, buildings are assembled as separate meshes under a common root, a ground plane lies beneath them by default, and coordinates are recalculated into meters from the center of the area. 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 format is handed over honestly: if neither OpenUSD nor the fallback pipeline managed to assemble the scene, the export returns an error rather than slipping you a glTF model with a .usda extension. The 3D extrusion area is limited to 1500 km² — over a larger area you get millions of meshes that no viewer will open.