NeoTerrain Diffusion

NeoTerrain Diffusion

This project is a NeoForge port of the original Fabric Terrain Diffusion Minecraft mod, which integrates the Terrain Diffusion world generation model into Minecraft.

Current Status

This port currently supports server-side use only.

It is intended for a NeoForge dedicated server. It is not currently a complete client-side replacement for the Fabric mod's world-creation flow, client UI, or single-player setup.

For this server, world setup is done through server.properties instead of the Minecraft client's Create World screen.

Validated Local Server

This implementation has been built and validated for:

• Minecraft 1.21.1
• NeoForge 21.1.233
• Java 21
• Windows 10/11
• DirectML GPU inference
• Dedicated server runtime

Validated jar:

terrain-diffusion-mc-neoforge-2.2.0-neoforge.1-windows+1.21.1.jar

The local server using this mod is:

C:\Users\Collin\Desktop\Server 1.21.1

Requirements

• A NeoForge 1.21.1 dedicated server
• NeoForge 21.1.233 or newer in the same 21.1.x line
• Java 21
• Windows with a DirectML-compatible GPU for the validated build
• About 1.5 GB free VRAM minimum
• About 2.5 GB additional system RAM for model loading
• Internet access on first launch so the model files can download

The validated local server launcher uses this Java 21 runtime:

C:\Users\Collin\AppData\Roaming\ModrinthApp\meta\java_versions\zulu21.48.17-ca-jre21.0.10-win_x64\bin\java.exe

GPU Behavior

The Windows build uses DirectML for GPU inference.

A correct startup should log:

Terrain diffusion inference: DirectML
ONNX model 'coarse' loaded on GPU
ONNX model 'base' loaded on GPU
ONNX model 'decoder' loaded on GPU

This port's Windows build is DirectML-first and should not warn about missing CUDA during normal startup. CUDA is not required for this Windows server build.

Server Installation

Place the NeoForge jar in the dedicated server's mods folder.

For this local server, the jar is kept in the linked Modrinth profile mods folder so the server sync step can copy it into:

C:\Users\Collin\Desktop\Server 1.21.1\server-runtime\mods

The sync script also omits known client/render-only mods from the server runtime using:

C:\Users\Collin\Desktop\Server 1.21.1\server-mod-exclusions.txt

Local Server

Run:

C:\Users\Collin\Desktop\Server 1.21.1\Start-Server.bat

That launcher:

1. Syncs server-compatible mods from the Modrinth profile.
2. Keeps excluded client/render jars out of server-runtime\mods.
3. Starts the NeoForge dedicated server with Java 21.

Creating A Terrain Diffusion Server World

Because this is currently a server-side port, configure the world in server.properties.

Current local server configuration:

level-name=terrain-diffusion-world
level-type=terrain-diffusion-mc\:terrain_diffusion

The active file is:

C:\Users\Collin\Desktop\Server 1.21.1\server-runtime\server.properties

On first launch, the mod downloads and prepares model files under:

C:\Users\Collin\Desktop\Server 1.21.1\server-runtime\terrain-diffusion-models

Configuration

The server config is created at:

config\terrain-diffusion-mc.properties

For this local server, the full path is:

C:\Users\Collin\Desktop\Server 1.21.1\server-runtime\config\terrain-diffusion-mc.properties

Current tuned values:

# Inference device: "cpu", "gpu", or "auto".
# On the Windows build, "gpu" means DirectML.
inference.device=gpu

# Keep all three models loaded on GPU instead of recreating DirectML sessions
# between pipeline stages. This is faster when enough VRAM is available.
inference.offload_models=false

# Validate SHA-256 for model files already on disk.
validate_model=true

# Local web UI port for /td-explore.
explorer.port=19801

# Terrain generation region side length in blocks. Must be a power of 2.
tile_size=256

# Spawn land-search coarse-pixel region sizes.
spawn_search.initial_size=16
spawn_search.max_size=128

If GPU memory becomes tight, set:

inference.offload_models=true

That lowers peak VRAM use but may slow generation.

Terrain Explorer

The port includes the server-side terrain explorer command:

/td-explore

Run it in game. The server prints a local web UI link, usually:

http://localhost:19801

Use the explorer to scout continents, mountains, islands, climates, and useful coordinates before traveling in game.

World Scale

The server-side port supports world scale values 1..6.

The default scale is 2.

For dedicated-server worlds, the selected scale is stored in the world save:

terrain-diffusion-world\data\terrain_diffusion_world_settings.dat

Scale behavior:

• scale=1 is more compressed and runs Terrain Diffusion more often.
• scale=2 is the default balance for playability and performance.
• Higher scale values cover more blocks per generated terrain sample and shift

more work toward Minecraft's CPU-side world generation.

Because this port is currently server-side only, there is no supported client world-creation Customize screen for changing scale in this setup. Treat scale as part of the server world save.

Common Issues

CUDA not available

This Windows DirectML build should not emit that warning. If it appears, the server is probably running an old jar or the wrong build variant. Reinstall the Windows DirectML jar and rerun the server mod sync.

DirectML not available

Update the GPU driver and confirm the machine has a DirectML-compatible GPU. To start without GPU acceleration for troubleshooting, set:

inference.device=cpu

CPU inference is much slower and is not recommended for regular server use.

A dynamic link library (DLL) initialization routine failed