Fast Biome Filler

A Minecraft Forge 1.20.1 mod for high-performance biome filling across large regions.

What it does

Provides a single command that changes all biomes within a bounding box to a target biome. Designed to handle massive regions as fast as possible.

Usage

/fastbiomefill <from> <to> <biome>

Examples:

/fastbiomefill 0 -64 0 1000 320 1000 minecraft:plains
/fastbiomefill ~-100 ~ ~-100 ~100 ~50 ~100 minecraft:desert
/fastbiomefill 0 0 0 500 256 500 minecraft:cherry_grove

• Requires operator permission (level 2+)
• Supports absolute and relative (~) coordinates
• Accepts any registered biome ID
• Reports the number of sections modified and time elapsed

Performance

Biomes in Minecraft 1.20.1 are stored at 4x4x4 resolution inside chunk sections. This mod operates directly at that level:

• Iterates by chunk section, not by individual block
• Writes directly to the PalettedContainer biome storage
• Fully enclosed sections are filled in a single sweep of 64 entries
• Edge sections only touch affected positions
• Chunk updates are batched and sent as full chunk packets to all tracking players

Installation

1. Install Minecraft Forge for 1.20.1
2. Drop the JAR from Releases into your mods/ folder
3. Start the server or singleplayer world

Building from source

git clone https://github.com/breakinblocks/fastbiomefiller.git
cd fastbiomefiller
./gradlew build

Output JAR will be in build/libs/.

License

MIT