Custom world generation/noise settings

• The root tag
  •  sea_level: The sea level in this dimension.
  •  disable_mob_generation: Disables passive mob spawning upon chunk generation.
  •  noise_caves_enabled: Whether the different noise caves generate.
  •  noodle_caves_enabled: Whether noodle caves generate.
  •  ore_veins_enabled: Whether ore veins generate.
  •  aquifers_enabled: Whether aquifers generate.
  •  legacy_random_source: Whether to use the old random number generator from before 1.18 for world generation.
  •  default_block: The default block used for the terrain.
    • Block state
  •  default_fluid: The block used for seas and lakes.
    • Block state
  •  structures: Structure settings
    •  stronghold: Settings for how strongholds should be spawned. The stronghold value under the  structures tag appears to be placeholders so that every structure has a value; these values are the ones that actually control stronghold spawning.
      •  distance: Controls how far apart the strongholds are.
      •  count: How many strongholds to generate.
      •  spread:
    •  structures: List of structures to use in this dimension
      •  <namespaced id>: The key for this field should be the namespaced ID of a structure, a list is available at Java Edition data value § Structures.
        •  spacing: Average distance between two structure placement attempts of this type in chunks.
        •  separation: Minimum distance between two structures of this type in chunks. Must be less than  spacing.
        •  salt: A number that assists in randomization; see salt (cryptography).
  •  noise: Parameters for world generation.
    •  min_y: The minimum Y coordinate where terrain starts generating. Value between -2048 or -2032 and 2031. Must be divisible by 16. Note that if -2048 is used, the bottom face of the, likely, bedrock floor won't be lit up correctly.
    •  height: The total height where terrain generates. Must be divisible by 16. Before 1.17, it squashes the world, for example, with height=128, the ground is set to Y=32. min_y + height cannot be higher than 2032 so its maximum is 4064 or 4080.
    •  size_horizontal: Changes the X/Z scale of the landmass, but not the biomes. E.g., increases the distance between mountainous terrain. Upper limit for this parameter is somewhere between 4 and 8.
    •  size_vertical: Changes the Y scale of the landmass. Values between 1 and 1.5 gradually increase the hill height, above 2.0 are all above the normal sea level of 63, and higher than 3.2 give normal land levels of 100+.
    •  island_noise_override: Optional. Causes the world to generate like The End with a big island in the center and smaller ones around.
    •  amplified: Optional. Toggles between amplified and normal terrain generation.
    •  large_biomes: Optional. Toggles between large biomes and normal biome generation.
    •  sampling: Specifies how the noise is sampled.
      •  xz_scale: Scales the X and Z axis of the noise. Higher values results in more intricate horizontal shapes. Works similarly to coordinate scale from old customized worlds.
      •  xz_factor: Smoothes the noise on the horizontal axis. Works similarly to main noise scale X/Z from old customized worlds.
      •  y_scale: Scales the Y axis of the noise. Higher values result in more intricate vertical shapes. Works similarly to height scale from old customized worlds.
      •  y_factor: Smoothes the noise on the vertical axis. Value can range from 0.001 to 1000.0. Works similarly to main noise scale Y from old customized worlds.
    •  top_slide: Settings for the curve at the top of the world.
      •  target: The value of the curve. Negative values round off the top of the hills in the affected area, positive values create a roof. Higher values produce larger effects.
      •  size: Defines the size of the affected area from the top of the world. Calculated using the formula size = <height in blocks> * 0.25 / size_vertical.
      •  offset: Moves the affected area from the top of the world. Uses the same formula as  size, so offset = <height in blocks> * 0.25 / size_vertical. For  top_slide, positive values move the area down and negative values bring it up.
    •  bottom_slide: Settings for the curve at the bottom of the world.
      •  target: The value of the curve. Negative values remove the floor and round off the bottom of the islands, positive values make a floor. Higher values produce larger effects.
      •  size: Defines the size of the affected area from the bottom of the world. Uses the same formula as in  top_slide.
      •  offset: Moves the affected area from the bottom of the world. Uses the same formula as in  top_slide. For  bottom_slide, positive values move the area up and negative values bring it down.
    •  terrain_shaper:
      •  offset: A terrain spline determining the offset of the terrain. Corresponds to the old  density_offset field but can now be configured depending on the dimension noises.
      •  factor: A terrain spline determining the factor of the terrain. Corresponds to the old  density_factor field but can now be configured depending on the dimension noises.
      •  jaggedness: A terrain spline determining the jaggedness of the terrain.
  •  surface_rule: Surface rule configuration for the terrain. This replaces the old surface builder system.
    •  type: Type of the surface rule, minecraft: with one of: condition, block, vertical_gradient, above_preliminary_surface, sequence, stone_depth, water, biome, y_above, not, noise_threshold, steep, hole or bandlands. See below of extra properties for each type.

The extra properties for  surface_rule per type:

• condition
  •  if_true: A surface rule that can give a true or false output
  •  then_run: A surface rule that does something

• block sets the blocks that reach this surface rule to the specified block
  •  result_state: The block to use
    •  Name: The namespaced id of the block to use.
    •  Properties: Block states
      •  state: A block state key and its value.

• vertical_gradient a conditional surface rule to select blocks in a gradient, used for deepslate and bedrock (between the specified y-coords is the gradient itself)
  •  random_name: any random name.
  •  true_at_and_below: the lower y-coord where this condition is true.
    •  above_bottom: the y-coord above the bottom of the world, mutually exclusive with absolute and below_top.
    •  absolute: the exact y-coord, mutually exclusive with above_bottom and below_top.
    •  below_top: the y-coord below the top of the world, mutually exclusive with above_bottom and absolute.
  •  false_at_and_above: the upper y-coord where this condition is false.
    •  above_bottom: the y-coord above the bottom of the world, mutually exclusive with absolute and below_top.
    •  absolute: the exact y-coord, mutually exclusive with above_bottom and below_top.
    •  below_top: the y-coord below the top of the world, mutually exclusive with above_bottom and absolute.

• above_preliminary_surface conditional surface rule, has no further properties

• sequence applies surface rules in order (only the first successful surface rule seems to be applied )
  •  sequence
    • a surface rule

• stone_depth conditional surface rule
  •  offset:
  •  add_surface_depth:
  •  secondary_depth_range:
  •  surface_type: either floor or ceiling

• water conditional surface rule
  •  offset:
  •  surface_depth_multiplier:
  •  add_stone_depth:

• biome conditional surface rule to test for the biome
  •  biome_is: list of biomes that result in true.
    • : namespaced id of the biome to check for.

• y_above conditional surface rule to check if it is above a specified y-coord
  •  anchor: the minimal y-coord where this condition is true.
    •  above_bottom: the y-coord above the bottom of the world, mutually exclusive with absolute and below_top.
    •  absolute: the exact y-coord, mutually exclusive with above_bottom and below_top.
    •  below_top: the y-coord below the top of the world, mutually exclusive with above_bottom and absolute.
  •  surface_depth_multiplier:
  •  add_stone_depth:

• not conditional surface rule, inverts the conditional surface rule within this
  •  invert: the surface rule to invert.

• noise_threshold conditional surface rule
  •  noise: default examples: minecraft: followed by one of: surface, surface_swamp, packed_ice, ice, powder_snow, calcite, gravel, patch, nether_state_selector, netherrack, nether_wart, soul_sand_layer or gravel_layer
  •  min_threshold:
  •  max_threshold:

• steep conditional surface rule, has no further properties

• hole conditional surface rule, has no further properties

• bandlands surface rule, used in badlands, has no further properties