MMD OreSpawn

MMD OreSpawn 4

MMD OreSpawn is a configurable world-generation engine for Minecraft Forge.
It gives players, modpacks, and other mods one place to control ores, rock
formations, underground fluid deposits, biomes, world materials, and related
world-generation settings.

OreSpawn does not register new blocks, items, creatures, or dimensions of its own. Mods such as Minecraft Mineralogy and Base Metals can supply content and ready-to-play settings, while OreSpawn validates those settings and performs the generation.

OreSpawn 4 documentation
| MMD project guide
| Source code
| Issue tracker
| MMD Discord

This is MMD OreSpawn, the world-generation library.

It is not the unrelated mod that adds creatures, girlfriends, the DangerZone,

and other adventure content.

Choose the right OreSpawn version

OreSpawn 4 and OreSpawn 3 are different generations with different
configuration formats. Use the documentation for the major version installed
in your pack.

Version · Intended use · Documentation
OreSpawn 4 · Current Forge versions, modern provider mods, new worlds, and current modpacks · Start with the OS4 guide
OreSpawn 3 · Legacy Minecraft 1.10 and 1.12 installations · Open the OS3 legacy guide

Use the Files tab above to select the build matching your exact Minecraft
and Forge version. Do not use OS4 as a drop-in replacement for OS3 in an old
pack.

What makes OreSpawn 4 different?

OreSpawn 3 already gave pack authors much better control over ore placement
than Minecraft's standard generators. It supported different deposit shapes,
weighted outputs and replacement blocks, biome filters, fractional
frequencies, custom dimensions, and retrogen.

Mineralogy later developed a much broader geology system. It could build rock
strata, choose geology from broad underground regions, let the surface biome
influence the rocks below it, and place ores and underground deposits in
suitable host materials.

OreSpawn 4 brings those ideas together as a shared engine.

A content mod still owns its blocks and gameplay. It can describe the rocks,
ores, deposits, biomes, or materials it wants to contribute. OreSpawn combines
the installed contributions with the pack's settings, checks that the
referenced content exists, and saves the final result with the world.

This means several compatible mods can use the same world-generation system
without each one trying to replace terrain or place ores independently.

Area · OreSpawn 3 · OreSpawn 4
Main job · Configurable ore placement · Shared engine for ores, geology, deposits, biomes, and world materials
Configuration · OS3 JSON files under config/orespawn3 · Provider defaults, pack overrides, templates, global settings, and a saved world profile
Content ownership · Configuration names the blocks to place · Each provider owns stable rules for its content
Geology · Replacement blocks and ore hosts · Geomes, rock families, depth preferences, and broad stable formations
Player setup · Mostly configuration-file driven · Create World editor, Recommended Defaults, tooltips, and an in-game guide
World safety · Pack authors coordinate generators · Validation, provider status, saved profiles, and deliberate retrogen controls

What OreSpawn 4 can manage

Rock strata and geomes

OS4 can replace ordinary underground host blocks with broad formations made
from provider or player-selected rocks.

The modern Sky system uses geological regions called geomes. The
surface biome influences which geome is likely below it, but geome boundaries
do not simply copy the biome map. Broad regional variation lets the same
geological province continue beneath several biomes, while boundary detail
keeps the edges from becoming straight walls.

Geomes can favour different rock families, such as sedimentary, metamorphic,
intrusive igneous, and volcanic rocks. Depth then helps choose which family
and which individual rock is suitable at a particular level.

The stable layers formation algorithm turns those choices into broad,
continuous formations with configurable reach, thickness, waviness, edge
detail, and continuity. The older Cyano (Legacy) layer style is also
available for players and migrated worlds that prefer the classic Mineralogy
look.

OreSpawn does not require rock strata. An ore-only mod can place its ores in
ordinary vanilla terrain while every geology control remains inactive.

Configurable ores

Each ore rule can control:

• Dimensions and Y ranges
• Attempts per chunk
• Fixed or ranged block quantities
• Uniform, centre-peaked, or deep-biased height distributions
• Host blocks, host tags, and configured rock families
• Included or excluded biomes and geomes
• Weighted output blocks and weighted hosts
• How much ore may remain visible on a cave wall
• Whether that rule participates in ore retrogen

Built-in deposit patterns include:

Pattern · Result
Compact · A dense, connected deposit
Vein · A wandering mineralised path
Normal cloud · A broad, diffuse deposit
Precision · A deterministic compact fill
Clusters · Several nearby connected nodes
Under fluids · A deposit placed beneath a selected fluid

Other mods can register their own pattern types through the public API.
Pattern settings are decoded and prepared before chunk generation rather than
being repeatedly parsed while blocks are placed.

Underground fluid deposits

Providers and packs can define covered underground pockets of water, lava,
oil, brine, or another installed fluid block.

Depth, frequency, radius, vertical shape, lobes, host materials, solid roof,
solid shell, biomes, and geome preferences can be configured separately. These
are deliberate underground deposits, not exposed vanilla lakes.

Biomes and world materials

OS4 can add provider biomes to an existing biome source or provide a complete
provider-controlled style where that is appropriate.

Dimension settings can also control surface and filler blocks, underwater
materials, aquifer fluids, a second deep aquifer fluid, snow, and ice.
Unconfigured dimensions keep their existing generator and materials.

Dimensions, templates, and vanilla features

Rules can target the Overworld, Nether, End, or installed custom dimensions by
registry ID. A named template can describe a complete optional world style for
a player or pack.

OreSpawn can also manage claimed vanilla ore features and flatten bedrock when
those options are deliberately enabled. Both are off unless the selected
profile asks for them.

Ways to use OreSpawn

Install it with a content mod

This is the normal player experience.

Mineralogy 6 supplies rocks, ores, crude oil, building content, and recommended
geology settings. Modern Base Metals releases can supply their metal ores and
placement rules. OreSpawn handles the shared world-generation work.

Install the matching OreSpawn build on both the client and server whenever a
mod lists it as a required dependency.

Configure a world yourself

OreSpawn can also be used without a full geology content mod.

When no provider supplies rocks, the rock editor can start with an editable
selection of suitable vanilla materials such as stone, deepslate, granite,
diorite, andesite, and tuff. You can add suitable blocks from installed mods,
remove materials you do not want, or leave strata disabled and configure only
the features you need.

Build a modpack

A pack author can:

• Tune provider rules without editing a mod jar
• Coordinate ore placement from several compatible mods
• Choose which dimensions and host materials each rule can use
• Select or create a complete world template
• Manage vanilla ores where the pack needs a single source of truth
• Ship global defaults that are copied into each new world
• Inspect provider status and the active profile with server commands

Test the final profile with the complete mod list before releasing a pack.
Missing blocks, removed providers, and conflicting native generators are much
easier to find in a fresh test world than in a player's established save.

Integrate another mod

Most integrations can be described in a provider file packaged at:

data//orespawn/provider.json

A provider may contribute only ores, or it may also contribute rocks, geomes,
fluid deposits, biome palettes, dimension materials, terrain dimensions, and
templates. Mods that need programmatic construction can use the supported
zone.moddev.mc.orespawn.api Java API.

OreSpawn is a normal required dependency. Do not shade or copy its engine into
another mod.

Creating a world

For a normal OS4 setup:

1. Install matching Forge builds of OreSpawn and its provider mods on the

client and server.

1. Open OreSpawn World Generation while creating the world.
2. Choose Recommended Defaults for the installed providers.
3. If you want to customise the setup, adjust the geology, rocks, ores,

deposits, biomes, or world materials before creating the world.

1. Use Help & Guide or the control tooltips when a setting is unfamiliar.
2. Press Done and create the world normally.

OreSpawn is deliberately passive when nothing opts in. Installing it alone
does not silently replace stone, remove vanilla ores, or change the Nether.

World profiles and servers

The final settings for a world are saved at:

/serverconfig/orespawn-worldgen.json

That file is a self-contained snapshot of the selected providers and settings.
Copy the whole world, including this file, when moving a single-player world to
a dedicated server. Install the same required mods on the server.

The global file:

config/orespawn-worldgen.json

provides defaults for newly created worlds. It does not replace the profile
already saved inside an existing world.

Changes normally affect only newly generated chunks. Rock strata are never
retro-generated. Ore and flat-bedrock retrogen must be enabled deliberately,
are revision tracked, and process a bounded number of chunks at a time.

Always back up a world before changing its mod list, profile, or retrogen
settings.

Useful commands

Command · Purpose
/orespawn status · Show the active mode, providers, rules, and retrogen state
/orespawn reload · Reload providers and the active world profile
/orespawn retrogen [radius] · Queue supported retrogen for currently loaded chunks
/orespawn dump-biomes · Export the biome IDs visible to the installation

Configuration files for packs

Location · Purpose
config/orespawn-worldgen.json · Defaults copied into newly created worlds
/serverconfig/orespawn-worldgen.json · The final profile belonging to one world
config/-orespawn.json · A pack's authoritative override for one provider
config/orespawn-guide/ · Documentation, examples, and schemas exported by the installed OreSpawn jar

A present provider override is authoritative. If it is malformed, that
provider stays inactive instead of silently falling back to a different set of
defaults. This makes configuration mistakes visible and avoids quietly
changing a pack's world generation.

Moving from OS3 or older Mineralogy settings

OS4 can import compatible settings from:

• OreSpawn 2 and 3 files under config/orespawn3/ and config/orespawn/
• Compatible flags in config/orespawn.cfg
• Mineralogy's config/mineralogy-geomes.json
• Older OS4 global, world, and provider schemas

The migrator understands OS3 quantities, height ranges, fractional frequency,
patterns, weighted blocks, biome filters, retrogen flags, and the old meaning
of an empty dimension list.

Migratio