Open Terrain Generator (OTG)

2,327,469 Downloads Last Updated: Oct 17, 2019 Game Version: 1.12.2

To learn about the mod in more detail visit our Wiki

* OTG V8 is out and it's a BIG update, be sure to read the changelogs and check out the new "O" menu for Forge! *


Note: When updating be sure to delete OTG-Core.jar from the 1.12.2 folder or it will not be updated.

Join us on the Discord at or github for questions or problems.


What is OTG?


OTG is a fully customizable world generator that allows users to design worlds via configuration files and share them with other players as their own mods, called OTG presets. Through configuration files, OTG preset creators have control over almost every aspect of Minecraft's terrain and structure generation, creating anything from floating islands to cave worlds with no knowledge of Java required. For Forge, OTG goes further and allows users to design custom dimensions with their own terrain, game rules and environmental effects, that can be easily imported and generated by OTG users via the ingame UI. Using all of OTG's features, you can design OTG dimensions for exploration, survival, pvp arena's, mini-games etc, package them as OTG presets and share them with the world as your own mods. OTG supports both Spigot (MP) and Forge (SP & MP).


OTG Presets: What kind of worlds can I create?


OTG configuration files are distributed as presets, single jar files that work just like normal mods. Users install an OTG preset just like a normal mod, by placing the mod jar in the mods folder along with the OTG jar. We hope to see many more OTG presets and preset creators in the future, join us on the Discord at and become part of the community!

The following OTG presets are currently available for download:


Be sure to check Curse and the OpenTerrainGenerator Discord at for new OTG presets!


The basic features of OTG

  • Control horizontal and vertical noise, terrain height and volatility, blocks used.
  • Create new biomes and control the size of biomes, islands and continents.
  • Import custom trees and other objects (BO2 and BO3).
  • Control over mob spawning rules and climate settings per biome.
  • Design large, procedurally generated custom structures such as dungeons, villages, cities, mountains, volcanoes etc with custom mobs and loot.
  • Options for vanilla structures like mineshafts, strongholds and villages.
  • Full control of all blocks placed during world generation: ores, plants, dungeons, ponds and many more.
  • Customizable options for caves & canyons.
  • Visual settings like custom foliage, water and sky colors (OTG client required).
  • Generate biome maps from images, or randomly based on your configurations and a seed (just like vanilla).
  • Forge pregenerator allows you to pre-generate any OTG dimension/overworld via the ingame "O" menu.
  • For Forge, OTG dimensions can be created/deleted on the fly via the in-game "O" menu.
  • For Forge since 1.12.2-v8, OTG can be used with existing non-OTG overworlds, OTG worlds can be added as dimensions, no need to start over!
  • Forge per-dimension settings can be edited via the in-game "O" menu, such as game rules and environmental effects (fog, lighting, day/night, weather, gravity, block-protect, add/remove items, respawn rules, join/leave message and many more).


OTG Wiki:

Subreddit: /r/openterraingen

Join us on Discord at: openterraingen

Github issue tracker: Github


Recent Improvements:

1.12.2 v8

Major changes


Forge & Spigot


- Dynamic biome id's: Newly created worlds allocate biome id's dynamically, which prevents biome id conflicts with other mods.




- Non-OTG overworlds: Use your existing (non-OTG) worlds with OTG and add OTG worlds as dimensions, no need to start over!
- New UI for world creation, managing OTG presets and editing per-dimension settings (also in-game, via the new "O" menu).
- Dozens of new dimension settings allow you to customise each OTG dimension or overworld with its own game rules and environmental settings (fog, lighting, day/night, weather, gravity, block-protect, add/remove items, respawn rules, join/leave message and many more).
- Lots of fixes and improvements for dimensions and portals. Define portal materials and create/edit/delete OTG dimensions via the in-game "O" menu.
- Lots of mod-compatibility fixes, including support for custom modded cave-gen such as Worley's and Yung's. There is still work to be done, but OTG should be a much better citizen in modded ecosystems.
- Lots of performance improvements, OTG should use less memory and generate terrain more quickly. This should be especially noticeable when using the pregenerator.

- OTG-Core fixes: OTG-Core now does nothing when OTG isn't installed. MC gives a warning if the wrong version of OTG-Core is present in the mods/1.12 folder (delete it manually and restart MC).

- Modpack config allows modpack creators to define an overworld+dimensions with OTG presets for newly created worlds, including seeds, without having to edit any presets. This way, modpack creators can package OTG + OTG presets with their modpack and include a modpack config file to ensure players (as the default settings) create the same worlds/dimensions with the same seeds.
- Improvements for OTG content creators, such as commands, error logging, fewer crashes due to incorrect settings and features for easily packaging and optimising/compressing OTG presets.


Minor changes


- Sapling settings: Grow OTG trees (or other BO3 objects) from saplings.
- Fixed MinHeight/MaxHeight for Tree(), which allows spawning of trees at specific heights.
- Added the ability to use modded biomes with replacetobiomename.
- Name your world anything, no worries about overwriting existing worlds.
- Removed /otg pregen command (use the "O" menu instead).
- Command names are now case-insensitive for Forge (biome / dimension names are still case-sensitive).
- Added preset clone button for SP (workaround to allow multiple dims with same preset).
- Replaced OTG worldborders with normal MC worldborders.
- Portals lead to the correct portal on the other side, no more sharing of portals between dimensions.
- Portals teleport correctly, so minecarts and players come out where they should.
- Players should spawn in oceans less often (><) for non OTG+ worlds.
- Fixed blockdata for ReplacedBlocks.
- Added concrete and concrete powder.
- Fixed a problem with oregen events not being called for Andesite, Granite and Diorite. This caused mods like Quark to not replace them correctly.
- Added missing biome decoration events for resources (trees, boulders, fossils, wells, underwaterore, surfacepatch, big mushroom, gravel, snow / ice / ice spikes). Other mods can now replace these OTG resources. *Still an event missing for snow/ice during population.
- Added missing worldgen events for vanilla structures (caves, strongholds, villages, mineshafts, temples/pyramids/witch huts etc, ocean monuments, woodland mansions). Other mods can now replace these OTG (vanilla) structures.
- Fixed file path problems for linux.
- SaveToDisk/Populate loop bug solved for all known cases.
- /otg tp is much faster now.
- Memory footprint of BO3's reduced.
- IsOTGPlus enabled BO3's are now called BO4's. Existing IsOTGPlus enabled BO3's are treated as BO4's. You can now use the .BO4 extension.
- Added /otg exportbo4data, which exports all BO4's for the current world as compressed/optimised .BO4Data files. Used when packaging OTG presets for users.


There are many, many more features and fixes. Be sure to check the /otg command for new features, as well as the ingame "O" menu and the world-, biome- and OTG-configs. We'll update the wiki soon, join us on the OTG Discord at if you have any questions!


Existing users


- OTG v8 is compatible with all existing v6-compatible presets and existing v6 worlds.
- Be sure to delete OTG-Core.jar from the mods/1.12.2 folder when updating.
- Set PregeneratorMaxChunksPerTick to 2 in OTG.ini for better pregeneration speed.
- Always back-up your files before updating!


Known issues


- Galacticraft crashes when switching planets. Will fix for the next release.
- For MP: If you're using a vanilla (non-OTG) overworld, make sure level-name in the is NOT set equal to an OTG preset name (f.e "Biome Bundle"), or you won't be able to use that preset via the "O" menu to create OTG dimensions. Will fix this for a future update.


Join us on the OTG Discord at if you have any problems or questions, or create an issue on the OpenTerrainGenerator git if you identify any technical issues. Team OTG thanks you for supporting OTG!


1.12.2 v6 / 1.11.2 v10 (1.11.2 v10 will be available soon):

  • Added GravityFactor setting to the worldconfig (this requires a Forge client with OTG). Forge only atm, can be used to change the gravity of a world/dimension.
  • Some fixes for dims when using other mods that add dims.
  • Smoothing fix for terrain (will cause minor seams in your world when entering newly generated terrain, looks much nicer though! See:
  • Savetodisk infinite loop fixed (one instance, there may still be more).
  • DIM folders being recreated on server restart bug fixed. - Fixed a bug for Lost Cities dimension.
  • Added a method for Spigot plugin developers (requested on the git).
  • Added TERRAIN_GENERATOR dimension tag when sending other mods (like RC) dimension info via Forge IMC when an OTG dimension is created/destroyed.
  • Frozensurfacehelper stackoverflow bug fixed (thanks BrainStone).
  • BO3 CustomStructures now try to avoid vanilla structures as much as they can.
  • Added /otg biomes command for Forge for debugging biome registry problems.


  • Fixes for all known crashes including ones caused by mods (excluding other biome mods which remain incompatible), including:
            - Dimension switching/mineshaft crash
            - Forge biome dictionary crash
            - Java preconditions crash
  • Fixed compatibility issues with a number of mods including Pam's Harvestcraft, IC2, Quark, Recurrent Complex, Roguelike Dungeons and more.
  • Added working Forge biome dictionary support for all biome types, added BiomeDictId option in BiomeConfigs (Forge Only)
  • Added new in game UI allowing simpler single player world creation and multiple worlds with the same preset (Forge Only)
  • Added a built in map pre-generator with in-game UI, configurable via world creation screen and WorldConfig (Forge Only)
  • Added world borders configurable in the WorldConfig
  • Basic multi-dimension support (more features and improvements will follow) (Forge Only)
    *Added Cartographer world mapper, a work in progress feature that adds a miniature map of the world that spawns in its own dimension and can be used to teleport around the world and explore quickly. (Forge Only)
  • Added InheritMobsBiomeName for BiomeConfigs and implemented mob inheritance (improves compatibility with mob mods) (Forge Only)
  • Fixed new worlds not generating dirs or default bc's, also tweaked default bc's to be more like vanilla Minecraft
  • Added Entity() function
  • Forge and Bukkit versions merged into a single .jar file


 For a comprehensive change log visit the Github project page here.