Planetary-Scale Streaming

Terrain is produced by noise functions evaluated on demand rather than stored, so what sits on disk is a set of rules instead of a map. Detail is generated at whatever resolution the current distance requires, and coordinates are handled at multiple scales to avoid arithmetic breaking down far from the origin. Result is a universe that exists only where someone is looking, and that looks identical to everyone who looks.

Hello Games shipped No Man's Sky in 2016 with a very small team and an ambition only procedural generation could satisfy, since no studio can author quintillions of planets by hand. Seamlessness was the pitch: flying from a planet's surface into space without a cut demonstrated that the whole thing was one system. Launch controversy centred less on the technology, which worked, than on what the generated worlds contained.

Scale at that magnitude buys awe and costs meaning, and the tension is the form's central problem. Generated variety is broad and shallow, so games built this way tend to layer hand-authored content, systems or other players on top. Technically the achievement stuck: continuous scale from centimetres to light years is now a solved engineering pattern, used by flight simulators and factory games with entirely different goals.