GrandTerrain

A Fabric mod for massive, realistic Minecraft world generation — towering mountains, deep multi-layer cave systems, underground rivers, and 16 custom biomes across a 1024-block-tall world — plus a web configurator to dial in the terrain and generate a downloadable world.

Built to pair with Voxy for extreme render distances, so the scale of the terrain is actually visible.

Status: early / experimental. The mod generates complete worlds in a dedicated server, but this is a young project targeting a bleeding-edge Minecraft version. Expect rough edges. Contributions and bug reports welcome.

Features

• Continental-scale terrain with ridged mountains, macro erosion, and Voronoi valleys
• Layered cave system: cheese caves, spaghetti caves, mega caverns, and underground rivers
• 16 custom biomes selected by a temperature/humidity/altitude climate model
• Config-driven structures (castles, ruins, dungeons, watchtowers) with biome filtering
• Fully configurable via an in-game Cloth Config screen or a grandterrain.properties file
• Web configurator for tuning every parameter and exporting/generating worlds

Requirements

	Version
Minecraft	26.1.2
Loader	Fabric 0.18.6+
Fabric API	0.145.4+26.1.2
Java	25
Voxy (optional, recommended)	0.2.16-beta+

Voxy is client-side and optional, but it's the reason the terrain scale is worth it — install it to render the world at far distances.

Repository layout

mod/     — the GrandTerrain Fabric mod (Java)
web/     — Next.js configurator: tune parameters, generate & download a world
worker/  — backend that runs a headless Fabric server to generate a world from a config

Running the full stack (web + worker)

# from the repo root; use your LAN IP so browsers can reach the worker
NEXT_PUBLIC_WORKER_URL=http://<this-host>:8080 docker compose up --build

Web configurator on port 3000, generation worker on port 8080. NEXT_PUBLIC_WORKER_URL is baked into the web bundle at build time and must be the worker address reachable from the browser (LAN IP, not localhost, unless you browse from the same machine).

Running the worker alone

cd worker
docker compose up --build

On first boot the container downloads everything it needs (Fabric server launcher, Fabric API, Chunky, and the GrandTerrain mod jar) into the mounted data/ volume. Each generation job boots a headless Fabric server, pre-generates a square region around spawn with Chunky, and packages the world into a downloadable zip.

Key environment knobs (see worker/.env.example for the full list):

Variable	Default	Meaning
PREGEN_RADIUS	2000	Pre-generation radius in blocks (2000 → a 4000×4000 area); 0 disables
PREGEN_TIMEOUT	21600	Hard cap in seconds; partial pre-gen still ships
MAX_CONCURRENT_JOBS	1	Generation jobs allowed at once
JOB_RETENTION_HOURS	24	Age after which job dirs and world zips are deleted

Rough sizing from a measured run (~17 chunks/sec on modest hardware): the default 2000-block radius is ~63k chunks — about an hour and a ~450 MB zip. Faster hardware scales roughly linearly.

Building the mod

./gradlew :mod:build
# artifact: mod/build/libs/grandterrain-<version>.jar

The build provisions JDK 25 automatically via the foojay toolchain resolver; a JDK 21+ is required to run the Gradle daemon itself.

Running the web configurator (dev)

cd web
npm ci
npm run dev

License

MIT © sworcery