Custom world generation/structure set

: Root object.
- structures: (Required, but can be empty) The structures that may be placed. One configured structure feature shouldn't be included by two structure sets.
  - : A structure to be placed.
    - structure: The configured structure feature to be placed. Can be a namespaced ID or an object of configured structure feature.
    - weight: Determines the chance of it being chosen over others. Must be a positive integer.
- placement: How the structures should be placed.
  - salt: A number that assists in randomization; see salt (cryptography). Must be a non-negative integer.
  - frequency: (Optional, default to 1.0) Probability to try to generate if other conditions below are met. Values between 0.0 to 1.0 (inclusive). Setting it to a number does not mean one structure is generated this often, only that the game attempts to generate one; biomes or terrain could lead to the structure not being generated.
  - frequency_reduction_method: (Optional, defaults to default) Provides a random number generator algorithm for frequency. One of default (the random number depends on the the seed, position and salt), legacy_type_1 (the random number depends only on the seed and position, and randomness only occurs when the locations differ greatly), legacy_type_2 (same as default, but with fixed salt: 10387320) and legacy_type_3 (the random number depends only on seed and position).
  - exclusion_zone: Specifies that it cannot be placed near certain structures.
    - chunk_count: Value betwenn 1 and 16 (inclusive).
    - other_set: A structure set ID.
  - locate_offset: (optional, defaults to [0,0,0]) The chunk coordinate offset given when using /locate structure.
    - : X. Value between -16 and 16 (inclusive).
    - : Y. Value between -16 and 16 (inclusive).
    - : Z. Value between -16 and 16 (inclusive).
  - type: One of minecraft:concentric_rings or minecraft:random_spread.
    If type is minecraft:concentric_rings (distributed like strongholds), additional fields are as follows:
  - distance: The thickness of a ring plus that of a gap between two rings. Value between 0 and 1023 (inclusive). Unit is 6 chunks
  - count: The total number of generation attempts in this dimension. Value between 1 and 4095 (inclusive).
  - preferred_biomes: Biomes in which the structure is likely to be generated. Can be a biome ID or a biome tag, or a list of biome IDs.
  - spread: How many attempts are on the closest ring to spawn. Value between 0 and 1023 (inclusive). The number of attempts on the Nth ring is: spread * (N^2 + 3 * N + 2) / 6, until the number of attempts reaches the total count.
    If type is minecraft:random_spread (distributed like bastion remnants or swamp huts), additional fields are as follows:
  - spread_type: (optional, defaults to linear) One of linear or triangular.
  - spacing: Average distance between two neighboring generation attempts. Value between 0 and 4096 (inclusive).
  - separation: Minimum distance (in chunks) between two neighboring attempts. Value between 0 and 4096 (inclusive). And be not bigger than spacing. The maximum distance of two neighboring generation attempts is 2*spacing - separation.

Custom world generation/structure set

Fan Feed