Command Line Usage

Command Line Usage

Arnis can run without the GUI. The release executables already include the command line mode: if you start Arnis with any arguments, it skips the window and generates straight from the terminal. Without arguments the GUI opens.

arnis-windows.exe --bbox="52.51,13.39,52.52,13.40" --output-dir="C:/YOUR_PATH/.minecraft/saves"

When you build it yourself, you can leave out the GUI completely with --no-default-features:

cargo run --release --no-default-features -- --bbox="min_lat,min_lng,max_lat,max_lng" --output-dir="C:/YOUR_PATH/.minecraft/saves"

For Java, --output-dir is the folder the new world gets created in (usually your saves folder). Arnis creates a new "Arnis World N" folder in there for every run.

With Nix you can run it directly:

nix run github:louis-e/arnis -- --output-dir=YOUR_PATH/.minecraft/saves --bbox="min_lat,min_lng,max_lat,max_lng"

Run arnis --help to see every option with its description. The rest of this page groups them by topic.

A note on on/off flags

Most flags are simple switches (--caves, --bedrock). Settings that are on by default take a value instead, so you can turn them off: --overture false, --canopy-height false, --map-item false. Writing just --overture means true. A few switches only exist to turn something off, like --no-3d.

Area and input

Flag	Default	Description
--bbox		Area to generate as min_lat,min_lng,max_lat,max_lng. Required, unless --file gives a local OSM file to read the area from. Below scale 0.3 and on the Moon or Mars no OSM data is loaded, so there it's always required.
--file		Read the OSM data from a local file instead of downloading it. Overpass JSON as well as .osm/.xml files work (no PBF). Without --bbox, the area comes from the file's bounds (<bounds> in OSM XML, or the area a --save-json-file run asked for), or else from the extent of its nodes.
--save-json-file		Save the OSM data the run uses to a file as Overpass JSON, together with the area, e.g. to generate the same area again later with --file. Can't be combined with --file.
--spawn-lat, --spawn-lng		Spawn point. Both have to be given and it has to be inside the area. Without it, Java worlds spawn at the corner of the area.

Output

Flag	Default	Description
--output-dir		Where the world goes. Required for Java. For Bedrock it's optional and defaults to the Desktop, for Luanti it defaults to the Luanti worlds folder. The old name --path still works.
--bedrock	off	Generate a Bedrock Edition .mcworld file instead of a Java world.
--luanti	off	Generate a Luanti world (Mineclonia game, map.sqlite) instead of a Java world. Experimental.
--one-world	off	Add the area to one persistent Java world instead of creating a new one. --output-dir is then the saves folder. See One World.
--world-name	Arnis One World	Name of the One World folder. Only works together with --one-world.
--map-preview	off	Also render a top-down PNG map of the generated world (Java and Bedrock).

Size and placement

Flag	Default	Description
--scale	1.0	Blocks per metre, from 0.05 to 4.0. Below 0.3 buildings and roads are skipped and only terrain and land cover are generated.
--height-multiplier	1.0	Makes the terrain taller or flatter, from 0.1 to 10. Buildings and trees keep their size.
--ground-level	-62	Base Y level of the world. In most cases you don't need to touch this: with an extended build height Arnis lowers the terrain on its own as far as it needs.
--rotation	0	Rotates the area clockwise, from -90 to 90 degrees. Not allowed with --one-world.
--projection	local	local puts the corner of every area at Minecraft 0,0. web_mercator centres the world on the area in a Web Mercator frame (the scale is exact at the centre latitude only). One World always uses its own Web Mercator frame.
--body	earth	earth, moon or mars. The Moon and Mars use NASA elevation data at a fixed scale (1 block = 200 m on the Moon, 500 m on Mars) and have no map data, so all object options are ignored.

What gets generated

Flag	Default	Description
--mode	geo-terrain	geo-terrain: buildings, roads and other OSM objects on real terrain. geo-only: the same on flat ground. terrain-only: real terrain with OSM water and nature, but no buildings, roads or other man-made objects. blueprint: roads, rails, water and nature on real terrain, with every building drawn as a light blue outline on the ground.
--winter	off	Snow on the ground, roofs and trees, frozen rivers and lakes and snowy biomes.
--post-apocalyptic	off	Collapsed and overgrown buildings, cracked roads, rubble and no lights.
--interior	off	Furnished interiors, picked by what the building is used for.
--fillground	off	Fill everything under the surface with stone and ores.
--caves	off	Carve Minecraft-style caves, underground rivers, ores and cave biomes into the filled ground. Turns on --fillground.
--cave-biomes		How much of each cave biome you get, as name=percent pairs. Names: lush, dripstone, deepdark, mushroom, ice, amethyst, volcanic, coral. 100 is the normal share, 0 turns a biome off, 200 roughly doubles it. Example: --cave-biomes lush=150,deepdark=0.
--cave-asset-pack		Folder with a cave asset pack (cave_pack.json plus .schem formations like ice spikes, dripstone columns and amethyst clusters). If there's a cave-pack folder next to the executable, that one is used.
--overture	true	Add buildings from Overture Maps that are missing in OSM, and take building heights from it where OSM has none.
--no-3d		Turns off the 3D landmark models and all bundled props (cars, boats, cranes and so on).
--signage	basic	none, basic (street names, traffic signs, transit stops, information boards, billboards) or full (adds shop name plates, house numbers and crossing signs). Java only.
--canopy-height	true	Place trees from the global canopy height map.
--legacy-trees	off	Use the old procedural trees instead of the tree models.
--max-tree-size	giant	Largest tree to place: small, medium, big, tall or giant.

World setup

Flag	Default	Description
--gamemode	creative	survival, creative or spectator.
--world-time	6000	Time of day in ticks: 0 = dawn, 6000 = noon, 18000 = midnight. Moon and Mars worlds start at midnight unless you set it.
--world-type	void	What Minecraft generates around the area: void or flat. Java only.
--map-item	true	Give the player a map. On Java it's a locked map of the whole world, on Bedrock the game's own starting map.

Building facades

See Building Facades for what these do.

Flag	Default	Description
--building-facades	off	Hang a bundled facade photo on every building, picked by building type. Java 1.21.4+. Turns the Mapillary facades off for this run.
--mapillary-token		Your Mapillary token. Can also come from the MAPILLARY_TOKEN environment variable. With a token, Mapillary facades are on.
--mapillary-facades	true with a token	--mapillary-facades false keeps the token but skips the facades.
--mapillary-facade-mode	photos	photos hangs the photos on the walls (Java 1.21.4+). blocks matches the wall blocks to the photos and works everywhere.
--facade-detail	standard	standard or high (sharper, needs a modern graphics card).
--facade-px	16	Texture resolution in pixels per block: 4, 8, 16 or 32. Lowered automatically if the panels wouldn't fit.
--mapillary-probe	off	Only check how much Mapillary coverage the area has, print it and exit.
--building-facades-dir		Use your own preset facade set (a folder with manifest.json and the images).

There are a few more --mapillary-* flags for debugging the facade pipeline (--mapillary-debug-dir, --mapillary-facades-dir, --mapillary-facade-debug-dir, --mapillary-facade-debug-walls). They're described in --help.

Gameplay extras

All of these come with a data pack in the world. They are Java only and don't work with --one-world yet. See Gameplay Extras.

Flag	Minecraft	Description
--pause-menu	1.21.6+	"Arnis" button in the pause menu with travel, discoveries and credits.
--discoveries	1.21.4+	Advancement tab for the area's landmarks, unlocked by walking there.
--traffic-lights	1.21.4+	Traffic lights that cycle red, amber and green.
--moving-vehicles	1.21.4+	Cars on the streets and trains, metros and trams on the tracks. --moving-cars works too.
--zombie-outbreak	1.21.6+	Five nights of zombie waves with a boss. Starts the world in survival.
--body-gravity	1.21.4+	Lower gravity on Moon and Mars worlds. Only with --body moon or --body mars.

Advanced

Flag	Default	Description
--disable-height-limit	off	Install the extended build height data pack (Java 1.21.4+: Y -2032 to 2031, Bedrock 1.21.40+: up to Y 511). Experimental, and not for Realms.
--aws-only-elevation	off	Use the legacy AWS Terrain Tiles (about 30 m) instead of Mapterhorn. Same as Legacy terrain in the GUI.
--bake-lighting	off	Precompute chunk lighting for LOD mods. Slower.
--voxy-lod	off	Pre-generate the Voxy LOD cache. Java only, turns on --bake-lighting.

Data sources and debugging

Flag	Default	Description
--osm-tiles-url	https://tiles.arnisproject.com/v1	Base URL of the Arnis OSM tile archive.
--no-tile-archive	off	Skip the tile archive and query the Overpass API directly.
--downloader	requests	How Overpass requests are made: requests (built in), curl or wget.
--overture-source	auto	Where Overture buildings come from: auto, tiles or parquet.
--timeout		Flood fill timeout in seconds.
--debug	off	Prints more output and writes debug files (parsed OSM data, land cover images) to the working directory.
--cave-zone-map		Renders the cave biome layout for --bbox to two PNGs (<PREFIX>-upper.png and <PREFIX>-deep.png) and exits without generating a world. --cave-zone-map-step sets the blocks per pixel.

The old --terrain flag is still accepted so older scripts keep working, but it does nothing anymore since terrain is on by default. Use --mode geo-only for flat ground.

Examples

A Bedrock world of central Munich at half scale:

arnis --bedrock --scale 0.5 --bbox="48.133,11.565,48.143,11.585"

A snowy Java survival world with caves:

arnis --output-dir="C:/YOUR_PATH/.minecraft/saves" --bbox="47.26,11.38,47.28,11.41" --winter --caves --gamemode survival

Adding an area to a One World:

arnis --one-world --output-dir="C:/YOUR_PATH/.minecraft/saves" --world-name="My City" --bbox="min_lat,min_lng,max_lat,max_lng"

The Copernicus crater on the Moon:

arnis --body moon --output-dir="C:/YOUR_PATH/.minecraft/saves" --bbox="8.6,-21.1,10.6,-19.1"