World Generation

Overview

World generation in Hytale is driven by a node-graph-based pipeline called HytaleGenerator. It produces terrain through layered noise functions, density maps, biome definitions, and weighted prefab assignments. Each component is defined in a separate JSON file and wired together through import/export references. The system supports procedural continent shapes, climate zones, cave networks, river carving, and per-biome scatter placement.

File Location

Assets/Server/HytaleGenerator/
  Assignments/
    Boreal1/
      Boreal1_Hedera_Trees.json
      Boreal1_Hedera_Mushrooms.json
      ...
    Desert1/
    Plains1/
    Volcanic1/
  Biomes/
    Basic.json
    Boreal1/
      Boreal1_Hedera.json
      Boreal1_Henges.json
    Desert1/
    Plains1/
    Volcanic1/
    Default_Flat/
    Default_Void/
  BlockMasks/
  Density/
    Map_Default.json
    Map_Portals.json
    Map_Tiles.json
    Plains1_Caves_Terrain.json
    ...
  Graphs/
  Settings/
    Settings.json
  WorldStructures/

Schema

Settings (Settings.json)

Field	Type	Required	Default	Description
`StatsCheckpoints`	`number[]`	No	—	Chunk-count thresholds at which generation statistics are logged.
`CustomConcurrency`	`number`	No	`-1`	Thread count for generation. `-1` uses the engine default.
`BufferCapacityFactor`	`number`	No	`0.1`	Fraction of total memory allocated to generation buffers.
`TargetViewDistance`	`number`	No	`512`	Target view distance in blocks used to pre-compute generation priority.
`TargetPlayerCount`	`number`	No	`3`	Expected player count used to size generation queues.

Density Node (node-graph files)

Density files define a tree of processing nodes that produce a scalar field used for terrain shape, river carving, or biome mapping. Every node has at minimum:

Field	Type	Required	Default	Description
`$NodeId`	`string`	Yes	—	Unique identifier for this node in the graph.
`Type`	`string`	Yes	—	Node type. See node types below.
`Skip`	`boolean`	No	`false`	When `true`, the node is bypassed during generation.
`ExportAs`	`string`	No	—	Name under which this node’s output is published for import by other graphs.
`SingleInstance`	`boolean`	No	`false`	When `true`, the node is evaluated once and cached globally.
`Inputs`	`DensityNode[]`	No	`[]`	Child nodes whose outputs feed into this node.

Common Density Node Types

Type	Description	Key Fields
`SimplexNoise2D`	2D simplex noise generator	`Lacunarity`, `Persistence`, `Octaves`, `Scale`, `Seed`
`Constant`	Outputs a fixed value	`Value`
`Sum`	Adds all input values	—
`Min` / `Max`	Returns the minimum or maximum of inputs	—
`Clamp`	Clamps input between two walls	`WallA`, `WallB`
`Normalizer`	Remaps a value range	`FromMin`, `FromMax`, `ToMin`, `ToMax`
`Inverter`	Negates the input	—
`Abs`	Absolute value	—
`Mix`	Blends two inputs using a third as alpha	—
`Scale`	Multiplies input coordinates	`ScaleX`, `ScaleY`, `ScaleZ`
`Cache`	Caches the result of child nodes	`Capacity`
`YOverride`	Forces a fixed Y coordinate for 2D evaluation	`Value`
`Distance`	Distance from origin with a falloff curve	`Curve`
`Exported`	Marks a node’s output for cross-graph import	`ExportAs`, `SingleInstance`
`Imported`	References an exported node by name	`Name`

Assignment (scatter/prefab placement)

Assignment files control what decorations, vegetation, or structures are placed in a biome region. They use a field-function approach with delimiters.

Field	Type	Required	Default	Description
`Type`	`string`	Yes	—	Top-level type, typically `"FieldFunction"`.
`ExportAs`	`string`	No	—	Export name for this assignment.
`FieldFunction`	`FieldFunction`	Yes	—	Noise function that produces the placement density field.
`Delimiters`	`Delimiter[]`	Yes	—	Ranges within the field function output that trigger placement.

FieldFunction

Field	Type	Required	Default	Description
`Type`	`string`	Yes	—	Noise type, e.g. `"SimplexNoise2D"`.
`Skip`	`boolean`	No	`false`	Bypass this function.
`Lacunarity`	`number`	No	`2`	Frequency multiplier per octave.
`Persistence`	`number`	No	`0.5`	Amplitude multiplier per octave.
`Octaves`	`number`	No	`1`	Number of noise octaves.
`Scale`	`number`	Yes	—	Spatial scale of the noise.
`Seed`	`string`	Yes	—	Seed string for deterministic generation.

Delimiter

Field	Type	Required	Default	Description
`Min`	`number`	Yes	—	Minimum field value for this range.
`Max`	`number`	Yes	—	Maximum field value for this range.
`Assignments`	`AssignmentNode`	Yes	—	What to place when the field value falls in this range.

AssignmentNode

Field	Type	Required	Default	Description
`Type`	`string`	Yes	—	`"Weighted"`, `"Constant"`, or `"Cluster"`.
`SkipChance`	`number`	No	`0`	Probability (0–1) of skipping placement entirely.
`Seed`	`string`	No	—	Seed for weighted random selection.
`WeightedAssignments`	`WeightedEntry[]`	No	—	Array of weighted options (when `Type` is `"Weighted"`).
`Prop`	`PropConfig`	No	—	Prefab/prop to place (when `Type` is `"Constant"` or within a weighted entry).

Example

Density map (Assets/Server/HytaleGenerator/Density/Map_Default.json, condensed to show structure):

{
  "$NodeId": "Exported.Density-ed27c3c9",
  "Type": "Exported",
  "ExportAs": "Biome-Map",
  "SingleInstance": true,
  "Inputs": [
    {
      "Type": "YOverride",
      "Value": 0,
      "Inputs": [
        {
          "Type": "Cache",
          "Capacity": 1,
          "Inputs": [
            {
              "Type": "Mix",
              "Inputs": [
                { "Type": "Imported", "Name": "Biome-Map-Tiles" },
                { "Type": "Constant", "Value": -0.3 },
                {
                  "Type": "Clamp",
                  "WallA": 0,
                  "WallB": 1,
                  "Inputs": [
                    {
                      "Type": "Normalizer",
                      "FromMin": 0.62,
                      "FromMax": 0.62,
                      "ToMin": 0,
                      "ToMax": 1,
                      "Inputs": [
                        { "Type": "Exported", "ExportAs": "World-River-Map" }
                      ]
                    }
                  ]
                }
              ]
            }
          ]
        }
      ]
    }
  ]
}

Generator settings (Assets/Server/HytaleGenerator/Settings/Settings.json):

{
  "StatsCheckpoints": [1, 100, 500, 1000],
  "CustomConcurrency": -1,
  "BufferCapacityFactor": 0.1,
  "TargetViewDistance": 512,
  "TargetPlayerCount": 3
}

World Masks — noise masks for continent shape, temperature, and climate
Environments — environment definitions assigned per zone
Instances — instance configs that select a world generation profile