Chunky for Minecraft: pregenerate a world safely

Choose a useful area

Decide which world, centre and exploration radius your group needs. Make a backup first and reserve storage for generated terrain, recovery copies and normal game data.

Doubling the radius roughly quadruples the area. A huge radius selected without a specific need can consume substantial computing time and storage. Start with a limited area, observe its cost and expand when justified.

Install and inspect the selection

Install a compatible build, restart and confirm loading. This example selects a circle with a 1,000-block radius in a world called world, centred on 0, 0. Adapt the world and centre to your save.

/chunky world world
/chunky shape circle
/chunky center 0 0
/chunky radius 1000
/chunky selection

Read the selection before starting. Nether, End and additional worlds require their own selections; selecting one world does not mean every dimension is prepared automatically.

Start, monitor and pause

During a quiet period, run /chunky start. Use /chunky progress to check progress while monitoring CPU, memory, free storage and server responsiveness.

If players are affected or resources approach a limit, run /chunky pause. Resume with /chunky continue. Prefer controlled interruption over killing the process. Once complete, inspect logs and retain an identified backup.

Do not use trim as an improvised undo command. It deletes chunks. Your original backup is the recovery point if you need to return to the previous world state.

Check whether generation was the problem

Compare exploration inside and outside the prepared area under a similar workload. If lag occurs within a small already-loaded area, investigate another cause. The RAM guide covers memory sizing; a spark profile helps establish where processing time is spent.

Pregeneration creates terrain using the current generation rules. A future biome update will not automatically make previously generated areas new again. Include that limitation when deciding how much terrain to prepare now.

Frequently asked questions