Underilla is a Paper based plugin for Minecraft Servers to 'merge' existing custom Minecraft word surfaces and vanilla undergrounds. It works by allowing the vanilla generation engine create chunks as normal, then intercepting the generator and forcing the surface of the original world, which works as a reference. In oder worlds, Underilla generates a brand-new world with vanilla undergrounds, but cloning the surface of an already existing world.
It's original purpose is adding vanilla caves to custom WorldPainter worlds, but it would perfectly work for any pre-generated world.
- 4 merging strategies:
- None: No actual vanilla underground noise is generated.
generate_noodle_caves
setting can still be on, to generate noodle caves. - Absolute: A Y coordinate value divides the original world surface and vanilla underground.
- Surface: Mix the original world surface and vanilla underground at a variable y that depends of original & vanilla world surface. It have the best racio generated world quality & performance.
- Relative: This strategie still need improvement, for now you should use Surface. The reference world's surface will be dynamically carved into vanilla underground; which means there's no actual height-based division.
- None: No actual vanilla underground noise is generated.
- Custom caves also supported. If using Relative merge strategy, every non-solid block and surroundings will be preserved, thus, if the reference world has itself an underground system, it'll be transferred over to the merged world.
- Heightmap fixed. Underilla re-calculates heightmaps when merging chunks, getting rid of floating and buried structures. Vanilla villagers and other structures are placed at the right height.
- Biome overwrite. Biomes from the reference world will be transferred and overwrite biomes from de vanilla seed being used. Cave biomes underground will be preserved.
- Java 21.
- A pre-generated world to use as a reference (Such as a WorldPainter world).
- A Paper (or forks) Minecraft Server of version [1.21 - 1.21.1]. It might work with upper version, but only 1.21.1 have been tested. Use old release for [1.19 - 1.20.6] compatibility.
Underilla is currently only implemented as a Paper plugin, so it runs only on Paper (or fork) servers. If you have a Vanilla, Forge or non Bukkit-based server; or looking for a single player experience; you may use a local Paper server to pre-generate a fully-merged world and then copy the resulting world folder to your actual saves
folder.
- Set up your Spigot (or fork) server.
- Download Underilla's
.jar
. - Place Underilla's
.jar
file into the./plugins
directory of your server. Create the folder if it doesn't exist already. - Into the
./plugins
folder, create a new folder calledUnderilla
and place aconfig.yml
file in it. You may get the file from this repo. - Open the
bukkit.yml
file in your server's root and add the following lines on top:This will tell Spigot to use Underilla's chunk generator.worlds: world: generator: Underilla
- In your server's root, create a new folder called
world_base
. - From the folder of your reference world, copy the
region
folder, and paste it into theworld_base
folder you just created. - If existing, delete the
world
folder fom your server's root. - (Optional) Open the
server.properties
file in your server's root, and tweak thelevel-seed
property. This has a direct impact on the generated underground. - Run the server. You'll notice Underilla generating merged chunks during world creation.
Important: Make sure your server's main world is still set to world
. Aside from this plugin, the server itself doesn't need to "know" about the reference world.
Underilla is significantly slower than the vanilla generator, as it doesn't relly on noise generation but on reading the reference world's region nbt
files and analyzing its patterns to 'clone' its surface to a vanilla world. So, if your world is intended for heavy duty in a big server. It's recommended to pre-generate the whole reference world area with a chunk generator plugin, such as Chunky. I'm planning adding a build-in pre-generation system in the future.
To increase generation speed you should edit worker-threads
in your config/paper-global.yml
to match your number of CPU cores, else paper won't use all CPU cores aviables. Using your number of core instead of default value usually double speed generation.
Huge map generation can takes hours or even days, here is some stats about performance to help you choose your configuration settings. All tests have been done on paper 1.20.4 on a 1000*1000 map generation of the same world painter generated world with default settings except strategy. We can't garanty that your computer will be as fast as mine, but it should be enoth to imagine how much time your world will need.
- Minecraft Vanilla generator (No Underilla) 1:36
- None strategy 3:25 (2.13 times longer than Vanilla generation)
- Absolute stategy 4:34 (2.85 times longer than Vanilla generation)
- Surface srategy 4:32 (2.83 times longer than Vanilla generation)
- Relative strategy 11:07 (6.94 times longer than Vanilla generation)
For a 50000 * 30000 world, it would take 40 hours to generate with Minecraft vanilla generator, 113 hours in surface strategie and 279 hours in relative.
- Underilla's generation disables Minecraft's chunk blender, which means there will be sharp old-school chunk borders at the edge of the reference world's chunks. This may be tackled by trimming your custom world chunks around the edges to generate blended chunks ahead of time.
- Due to Spigot's generation API, outside the reference world's area, heightmaps are broken, which has an impact on structures. You may work around this by pre-generating the whole reference world area, and then disabling Underilla.
- Relative strategy only: Little underground lava and water pockets will translate to odd floating blobs in the final world if they overlap with large caves. Avoid such generation patterns.
If you're going to plug your custom WorldPainter world into Underilla, consider before exporting:
- Disable caves, caverns, and chasms altogether, allow Underilla to take over that step. This is due to biome placement, every underground non-solid block in the reference_world drags its biome over along with it, this interferes with proper underground vanilla biomes.
- Always disable the
Allow Minecraft to populate the entire terrain
option. Rather use thevanilla_population
option in Underilla'sconfig.yml
file. - Don't user the resource layer. Underilla will have the vanilla generator take care of that for you.
- The Populate layer has no effect. Weather all or none of the terrain will be populated based on the above point.
- If you have custom cave/tunnels layers and want to preserve them during the merge, you'd want to use the Relative merge strategy
Cave generation on custom biomes is now working. Features (ores, flowers etc) will be placed according to the custom surface world biome but structures won't. If you have a custom world with custom biomes, you should enable custom biome it in the config.
If you want to remove some of the game features, for example the monster_room
you can create a datapack where you have customine witch feature can spawn in each biome. Underilla will generate feature according to your cusomized biome.
It can also be used to add feature to some biome. For example a quartz_ore feature if your nether is disabled you you still want your builder to have quartz.
Create a working jar with ./gradlew buildDependents
- Build-in pre-generation system.
- Allow to generate the 2nd world on the fly.