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NBT‐Placement

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Waterpicker edited this page Jul 21, 2026 · 1 revision

NBT Placement

Package: org.dimdev.limlib.api.world

NBT placement is used by AbstractNbtChunkGenerator to load structure files and place them during world generation.

NBT Groups

NbtGroup maps sub-group names to structure names. Given a group ID, sub-group, and piece name, it resolves this path:

structures/nbt/<group_id_path>/<sub_group>/<piece>.nbt

For example, group example:demo, sub-group rooms, and piece room_a resolve to:

example:structures/nbt/demo/rooms/room_a.nbt

Use NbtGroup#pick(...) to choose a random piece from a sub-group. NbtGroup#fill(...) resolves the group's pieces and adds them to a FunctionMap.

Loading and Manipulation

NbtPlacerUtil reads compressed structure NBT from a ResourceManager. It keeps the block states, optional block entity data, entities, lowest position, and structure size.

Call NbtPlacerUtil#manipulate(...) before placement to rotate or mirror the structure. Manipulation combines Minecraft's Rotation and Mirror values.

Supported codec names include:

  • none
  • clockwise_90
  • 180
  • counterclockwise_90
  • front_back
  • left_right
  • top_left_bottom_right
  • top_right_bottom_left

Placement Behavior

AbstractNbtChunkGenerator#generateNbt(...) places the loaded blocks and spawns entities in a WorldGenRegion.

By default:

  • air block states are skipped
  • barriers are replaced with air
  • block entity NBT is loaded when the block entity exists and matches the placed block
  • RandomizableContainerBlockEntity receives the simple dungeon loot table unless getContainerLootTable(...) is overridden

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