Pre-generation

Pre-generation creates chunks ahead of time so they’re ready on disk before players arrive. This is useful for map rendering, reducing lag during exploration, or preparing event areas.

Config-based Pre-generation

Set a pregenerateRegion in the world config to automatically generate chunks on world load using /world settings:

/world settings pregenerate set -2500 -2500 2500 2500

The arguments are block coordinates: min x, min z, max x, max z. The example above creates a 5000×5000 block region centered at the origin (-2500 to +2500 on each axis). The server generates all chunks within this region when the world loads.

The region is stored in config.json under chunkConfig.pregenerateRegion:

{
  "chunkConfig": {
    "pregenerateRegion": {
      "min": { "x": -2500.0, "y": -2500.0 },
      "max": { "x": 2500.0, "y": 2500.0 }
    }
  }
}

To clear the region:

/world settings pregenerate reset

Chunk saving

Pre-generated chunks enter the normal chunk lifecycle and are saved to disk automatically. You can force an immediate flush with:

/world save --confirm --all

Benchmark Command

/worldgen benchmark also generates chunks in a region, but it’s designed for performance measurement, not pre-generation:

/worldgen benchmark -2500 -2500 2500 2500

Keep-loaded Region

Separate from pre-generation, you can define a region that stays loaded in memory:

/world settings keeploaded set -500 -500 500 500

This keeps chunks loaded even when no players are nearby, which is useful for always-active areas (spawn, arenas). Chunks in this region are also generated if they don’t exist.

Chunks — chunk loading, generation flags, and indexing
Chunk Saving — how chunks are persisted to disk
Storage Format — world directory structure and config