Terrasect

What is Terrasect?

Terrasect lets you divide your Minecraft world into named regions — laid out as a hex grid, Voronoi cells, recursive subdivisions, surround shapes, or scattered islands — and give each region its own rules for how the world generates there. One region can be a lush, gentle plain; its neighbor a jagged, monster-infested wasteland with its own loot table — all in the same world, all from the same seed, every time.

Nothing here is random per-visit: the same seed always produces the same layout, so a region you found once will still be there next time.

Issues and suggestions

Found a bug, or have an idea for something Terrasect should do? Open an issue on the GitHub issue tracker — bug reports and suggestions are both welcome.

Features

• Terrain & climate shaping. Push a region's terrain flatter or rougher, and override its temperature, humidity, and other climate values independently of the surrounding world.
• Height limits. Cap how high or low a region is allowed to build.
• Structure control. Allow, block, or force specific structures (or whole mod/structure-tag groups) inside a region — want every plains village replaced with a pillager outpost? Done.
• Mob spawn control. Allow or block specific mobs (or entire mob tags) from spawning in a region, both during world generation and during normal play.
• Loot control. Allow or block loot table entries (or loot tags) inside a region.
• Five ways to lay out regions. Hex grid, Voronoi cells, recursive subdivision, surround shapes, and scattered archipelagos — pick whichever shape language fits the world you're building.
• Simple config, or code if you want it. Define regions in plain text preset files, or build them programmatically if you're writing your own add-on.
• Built to stay fast. Region lookups are cached per chunk, so adding a lot of regions doesn't mean a laggy world.

Supported versions

Fabric builds additionally require Fabric API and Fabric Language Kotlin. NeoForge builds additionally require Kotlin for Forge. Grab the matching dependency versions from the same release page as the Terrasect jar you download.

Quick start

1. Install Terrasect and its loader-specific Kotlin dependency (see above) like any other mod.
2. Launch the world once — Terrasect creates a config/terrasect/ folder with an example preset and a config.toml file. No preset is active yet at this point, so world generation is untouched.
3. Open config/terrasect/config.toml and set preset to the name of a preset file in that folder (without the .toml extension) to activate it.
4. Restart the game or server. Config changes are only read on startup.

See Getting Started below for a step-by-step walkthrough, the complete region/strategy reference (with pictures), and dedicated pages for noise, structures, and loot constraints.

Known limitations

Terrasect is under active development. A few preset options are accepted today but don't yet change generation: restricting a region to specific biomes, enforcing a region's height limits, and overriding precipitation or an inherited climate preset. These are recognized and validated, just not wired up to world generation yet — check the project's Known Issues page for the current state before relying on them.

License & AI disclosure

Terrasect is MIT licensed — use it, fork it, learn from it.

LLMs were used extensively in building this mod, and some of the codebase is admittedly rough around the edges as a result. The point of this project was the idea — region-based world generation control — not a polished implementation. If you want to take the idea further in your own mod, you're encouraged to; we'd love to hear about it.