Terrasect

Download: Modrinth · CurseForge

Terrasect is a multiloader (Fabric + NeoForge) Minecraft world generation mod. It lets you carve a dimension into named regions — using hex, Voronoi, and other tiling strategies — and attach constraints to each region: noise, climate, height, biome, structure allow/block/force rules, mob spawn rules, and loot table rules. Regions are declared in TOML presets or through a Kotlin DSL, and are resolved deterministically per-seed at world generation time. Region boundaries are resolved via signed distance fields, the hot path is designed to be allocation-free, and results are cached at the chunk level so per-block lookups stay cheap.

User-facing docs: https://let-value.github.io/terrasect/ (built from pages/, published on release — this repo's docs below are for contributors).

Important

AI disclosure. LLMs were used extensively in developing this mod. We acknowledge that some parts of the codebase are poorly written and may contain bugs or AI-generated slop. The author doesn't have the time, resources, or Java/Kotlin expertise to fully support an intricate codebase like this one. The point of this project was the idea, not the implementation: region-based world generation constraints is a genuinely good idea that deserved to exist. Ideas can't be copyrighted, and AI-generated code even less so — everyone is encouraged to fork this project or recreate the idea from scratch.

Supported Minecraft versions

MC version	Loaders	Notes
1.20.1	Fabric	Back-compat target (Loom-based build, no client gametests)
1.21.1	Fabric, NeoForge	Back-compat target
1.21.11	Fabric, NeoForge	Back-compat target
26.1	Fabric, NeoForge
26.2	Fabric, NeoForge	Latest; primary / active development version

One shared codebase targets every version above via Stonecutter source preprocessing plus a small compat-shim layer — see docs/MULTIVERSION.md.

Project Structure

terrasect/
├── common/          # All shared logic — mixins, region model, generation pipeline, handlers
├── fabric/          # Fabric entrypoints only
├── neoforge/        # NeoForge entrypoints only
├── compat/c2me/     # Git submodule — optional C2ME-fabric performance compat
├── e2e/             # Fabric client gametests (separate Stonecutter matrix)
├── e2e-compat/      # Third-party mod compatibility gametests
├── versions/        # Stonecutter-generated per-version projects — git-ignored, do not edit
├── settings.gradle.kts       # Stonecutter version matrix
├── stonecutter.gradle.kts    # Active dev version + Spotless config (no separate root build.gradle.kts)
└── gradle.properties

common/, fabric/, and neoforge/ are not themselves buildable Gradle projects — every buildable project is version-qualified (:<version>-<loader>, e.g. :26.2.x-fabric).

See docs/PROJECT_MAP.md for the full package-by-package architecture reference.

Building

Build every version/loader combination:

./gradlew build

Build a specific version/loader:

./gradlew :26.2.x-fabric:build
./gradlew :26.2.x-neoforge:build

Running

./gradlew :26.2.x-fabric:runClient
./gradlew :26.2.x-fabric:runServer
./gradlew :26.2.x-neoforge:runClient
./gradlew :26.2.x-neoforge:runServer

Swap 26.2.x for any other version project in the support matrix above (e.g. 1.21.11-fabric).

Testing

./gradlew :26.2.x-common:test                    # unit + snapshot tests
./gradlew :26.2.x-common:test -PupdateSnapshots  # regenerate snapshot references
./gradlew :e2e:26.2.x:runClientGameTest          # client gametests for a given version

Configuration

Terrasect loads TOML presets from <game>/config/terrasect at startup. See docs/CONFIGURATION.md for the full schema, and docs/KNOWN_ISSUES.md for config properties that are currently parsed but not yet wired to runtime behavior.

Development

• Code style: enforced by Spotless — ktfmt (Google style) for Kotlin, google-java-format for Java. Run ./gradlew spotlessApply before committing; ./gradlew spotlessCheck is what CI checks.
• Shared logic lives in common/. Loader modules (fabric/, neoforge/) only provide entrypoints and lifecycle hooks — see docs/PROJECT_MAP.md.
• Releasing: see docs/RELEASING.md for the CI/release/publish workflow.

Contributing

Issues and pull requests are welcome.

1. Fork the repo and branch off main. Keep each PR focused on one change; unrelated cleanup belongs in its own PR.
2. Match the existing code style. Run ./gradlew spotlessApply before committing — spotlessCheck is enforced in CI. Prefer direct, comment-free code over abstractions or compatibility wrappers; see the guardrails in AGENTS.md.
3. Test your change. Run ./gradlew :26.2.x-common:test for anything touching common/, and add or update snapshot/unit tests alongside the change. If your change touches a mixin or anything version-divergent, it must pass SmokeGameTest across the client gametest matrix (see docs/MULTIVERSION.md) — a green compile proves nothing about whether a mixin actually applies at runtime on every version.
4. Open the PR against main with a short description of what changed and why, and which commands you ran to verify it.

Given the AI disclosure above, AI-assisted contributions are perfectly welcome here — just make sure you've actually run and verified the change yourself before opening the PR.

For anything beyond a small fix — new constraint types, new strategies, structural refactors — open an issue first to discuss the approach.

Related Projects

Terrasect isn't the first or only mod exploring region-based world generation control, and it won't be the last — see the AI disclosure above. We'd rather point people at the wider ecosystem than pretend this is the only option.

Prior art / predecessors:

• (none listed yet — if you know of an earlier mod that explored this space, open a PR adding it here)

Similar / newer projects:

• (none listed yet — open a PR to add yours)

If you maintain a mod with similar goals (old or new), open a PR adding it to one of the lists above, and feel free to link back to Terrasect from your own README. We're happy to return the favor.

License

MIT License. See LICENSE for details.