Chunk Remover

Chunk Remover

A NeoForge mod for Minecraft 1.21.1 that lets you select an area on the FTB Chunks map and delete every
generated chunk inside it. The chunks are regenerated normally the next time someone visits them, and the
world save shrinks accordingly.

Why

In a heavily modded world, players explore and generate far more terrain than in vanilla, both to find
modded resources and because modded transport is fast. The number of generated chunks explodes and the save
grows by gigabytes. Most of that terrain is never visited again. Chunk Remover lets an admin erase those
chunks from the save while keeping the world coherent, since they come back exactly as the world generator
would have produced them (same seed, same mods).

Requirements

The mod must be installed on the client (map integration) and on the server (deletion). In singleplayer
both run in the same game.

Usage

From the FTB Chunks map

1. Open the large map (default key M).
2. Click the bin icon in the lower part of the button bar on the left. It is only shown to operators and
   to the owner of a singleplayer world.
3. Drag with the left mouse button to select an area. Hold Shift while dragging to add more
   rectangles. The middle button pans the map while the tool is active, right click clears the selection,
   Esc or the bin icon leaves the tool.
4. Press Enter or Delete and confirm. The chunks disappear from the save and from your map.

The server replies with a summary in chat: chunks deleted, chunks skipped, region files removed or rewritten,
disk space freed.

From a command

/chunkremover delete chunks <x1> <z1> <x2> <z2> [dimension]   # chunk coordinates
/chunkremover delete blocks <x1> <z1> <x2> <z2> [dimension]   # block coordinates

Both corners can be given in any order. The dimension defaults to the one the command is run in. The command
works from the server console too.

What is never deleted

• Loaded chunks: anything near a player, force-loaded (vanilla /forceload, FTB Chunks force-load, other
  mods), spawn chunks, or currently being generated, loaded or saved.
• Claimed chunks (any team in FTB Chunks), unless protectClaimedChunks is turned off in the config.
• Chunks that were never generated are simply reported as "not generated".

The deletion still cannot be undone. Make a backup first.

Configuration

config/chunkremover-common.toml

Things to know

• Regenerated chunks match the original generation only if the world seed and the installed mods are the
  same. If world generation mods changed since the area was generated, you will see chunk borders.
• Player-built structures in the selection are lost; that is the point, so select carefully.
• Structures (villages, modded dungeons…) regenerate at the same places because generation is deterministic.

License

MIT, see LICENSE.