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Underilla

Get vanilla minecraft caves in a custom world.

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Paper26.2

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3.0.0

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  • Requires Java 25 and targets Paper 26.2. Chunky and VoidWorldGenerator are still used for pregeneration and out-of-bounds chunks; the configured setup step can download them.
  • Existing configurations need migration: replace surfaceWorld.name and cavesWorld.name with worldPath and dimension in each section. The default source layout is <worldPath>/dimensions/minecraft/overworld/region; use regionPath for a different layout. Set surfaceWorld.entitiesPath when entity files cannot be resolved from the world and dimension.
  • Reference-world entities can now be copied from entity region files into newly generated chunks. If no entity region directory is available, generation continues without copying them.
  • Replace cache.size with cache.regionFiles (default 16) and cache.chunks (default 64). The chunk cache reduces repeated source-world reads; values below 32 may substantially slow generation.
  • Use namespaced block, biome, and entity IDs in configuration, such as minecraft:sand and minecraft:item. Unqualified IDs use the minecraft namespace. Block and entity regex patterns now match complete namespaced IDs, so existing patterns should be reviewed.
  • Block support and replacement cleanup now runs during generation, and entity removal runs when a newly generated chunk loads. Remove steps.cleaningBlocks and the previously misspelled steps.cleaingEntities from existing configurations; only steps.underillaGeneration needs to be reset to todo for a new generation pass.
  • clean.blocks.removeUnstableBlocks now checks newly generated chunks after they load. The end-of-generation block transformer hook was removed; plugin integrations using it must be updated.
  • vanillaPopulation.enabled now controls mob generation as well as feature generation.
  • Improved terrain and cave merging, including filling gaps between a high reference surface and lower generated terrain when no separate caves world is supplied, and preserving configured reference terrain around cave carvers.
  • The bundled biome-merging list now includes minecraft:sulfur_caves.
  • Generation timings and aggregate statistics are written to plugins/Underilla/metrics.json during generation and on shutdown.
  • The bundled example datapacks and test worlds have been removed. Bring your own datapack when customizing vanilla features or cave generation.
  • The Java integration packages moved from fr.formiko.mc.underilla to com.kntrel.mc.underilla; downstream plugins and libraries must update their imports. The project now builds separate core and Paper modules.
  • Pushes to main build and run tests. When the project version increases, the release workflow creates a v tag and publishes the JAR to GitHub Releases and Hangar. Modrinth and Maven Central publishing are no longer configured.

Information

Published
September 21, 2026
Author
kntrel
6Downloads

Platforms

Paper
Paper
26.2