Zones / Locations / Vegetation

The world of Valheim is split up into Zones, each 64 by 64 meters, controlled by the ZoneSystem. Each Zone can potentially have a single Location instance, and many Vegetation instances.

Locations

Locations are bundles of objects that are placed randomly during world generation. These include the boss altars, crypts , Fulin villages and more. For a full overview, check the Locations list

These are unpacked only when a player gets close to the position of a placed location. Once unpacked, the GameObjects are saved like regular pieces.

Only GameObjects with a ZNetView.m_persistent = true will be saved and instantiated on load after unpacking.

Each Zone can contain only 1 location. This means that the number of slots is limited. Try to keep the total number of locations added low so everything has a chance to place.

Vegetation

Vegetation are singular prefabs that are scattered in a Zone. This is most of the spawned objects:

  • Plants & trees
  • Rocks: both normal stone & ore spawns
  • Leviathans
  • Ice in the Deep North
  • Non-interactable effects like fireflies & mist

There is no limit to the number of vegetation in a single zone.

World generation

Valheim's worlds are procedurally generated exactly once using a provided seed.

Locations

When a new world is generated, the game goes through the list of available locations. The list is sorted so all locations with Prioritized = true are handled first.

The game will attempt to place Quantity instances of each location, it will attempt up to 100.000 times, or even 200.000 if it is Prioritized!

Every time it selects a random Zone and checks if there are no other location instances in this zone already and if the Zone matches the BiomeArea (in the middle of a Biome, or on the edge between different biomes)

If these checks succeed, it will then attempt to actually fit the location into the terrain up to 20 times (for this selected zone)

This is when the filters are used, everything is checked on the center of the location:

Property Effect
MinDistance
MaxDistance		 The distance between the center of the world and this location should be between these values
Configuring value 0 will match any distance
Biome The location must be in a biome that matches this field. You can specify multiple biomes for a single location, any of these will match.
MinAltitude
MaxAltitude		 The height of the location should be between these values. 0 is the shoreline.
InForest
ForestThresholdMin
ForestThresholdMax		 If enabled, the value of the forest fractal in the seed of this location must be between these values
0 is the center of the forest.
1 is on the edge of the forest
Above 1 will move the location further from the forest edge
MinTerrainDelta
MaxTerrainDelta		 The game will sample 10 random points in the circle defined by ExteriorRadius and calculate the local mininum and maximum height. The difference between these values is the TerrainDelta, which should be between the configured values.
DistanceFromSimilar Check for other instances of the same location, or from the same Group if configured, if any are found within this range, this filter will fail
This is disabled by default with value 0

Once a location passes all the checks it is registered to that location.

If a location fails to place all Quantity instances, the game will print a warning in the log.

When a player gets close to this zone for the first time, the location prefab is placed with these properties

Property Effect
SnapToWater If enabled, spawns the location at the water level height instead of ground height (only useful if Altitude checks < 0)
ClearArea Mark the area defined by ExteriorRadius to not spawn any Vegetation
SlopeRotation If enabled, will rotate the location to face the slope. Priotized over RandomRotation
RandomRotation If enabled, will rotate the location randomly. Will be ignored if SlopeRotation is enabled

Vegetation

Vegetation is placed when a Zone is first discovered. The game will go through all available Vegetation, and attempt to place each type according to its configuration.

The number of attempts is determined by:

Property Effect
Max Maximum amount of groups in the zone
Values between 0 - 1 are used as a percentage chance to spawn a single group in this zone
Min If the value of Max is above 1, this is used as the minimum number of groups
GroupSizeMin
GroupSizeMax		 Number of instances in each group. The game will attempt to place this many, but there are no guarantees any will actually place

Every attempt to place an instance of a Vegetation will go through these checks:

Property Effect
BlockCheck If enabled, does a raycast down and check if there are no objects in the way on these layers
  • Default
  • static_solid
  • Default_small
  • piece
These objects are either part of a Location, or another Vegetation that was already placed
Biome The vegetation must be in a biome that matches this field. You can specify multiple biomes for a single vegeation, any of these will match.
BiomeArea Check the position within a Biome, either in the middle of a Biome, or on the edge between different biomes
MinAltitude
MaxAltitude		 The height of the vegetation should be between these values. 0 is the shoreline.
MinOceanDepth
MaxOceanDepth		 If these values are not equal, check that the value of the OceanDepth from the seed is between these values.
This is not the same as Altitude, not entirely sure how to interpret this
MinTilt
MaxTilt		 Checks the slope of the terrain mesh at this point, using the normal of the mesh
In degrees: 0 is flat ground, 90 is a vertical wall
MinTerrainDelta
MaxTerrainDelta		 Only enabled if the TerrainDeltaRadius is not 0
The game will sample 10 random points in the circle defined by TerrainDeltaRadius and calculate the local mininum and maximum height. The difference between these values is the TerrainDelta, which should be between the configured values.
InForest
ForestThresholdMin
ForestThresholdMax		 If enabled, the value of the forest fractal in the seed of this vegetation must be between these values
0 is the center of the forest.
1 is on the edge of the forest
Above 1 will move the vegetation further from the forest edge

Locations have a property ClearArea, enabling this will prevent any vegetation from spawning in the ExteriorRadius of the location.

ZoneManager

Jötunn provides a ZoneManager singleton for mods to interact with the ZoneSystem of Valheim.

Timing

Locations and Vegetation are loaded during world load. Use the event ZoneManager.OnVanillaLocationsAvailable to get a callback when the locations are available for use. This is called every time a world loads, so make sure to only add your custom locations & vegetations once.

Modifications to vanilla locations & vegetation must be repeated every time!

Locations

Jötunn uses the LocationConfig together with CustomLocation to define new Locations that will be injected into the world generation.

Modifying existing locations

Use ZoneManager.Instance.GetZoneLocation to get a reference to the ZoneLocation.

You can add prefabs to the m_locationPrefab to add them wherever this location is placed:

var eikhtyrLocation = ZoneManager.Instance.GetZoneLocation("Eikthyrnir");
var lulzCubePrefab = PrefabManager.Instance.GetPrefab("piece_lul");

var eikhtyrCube = Instantiate(lulzCubePrefab, eikhtyrLocation.m_prefab.transform);
eikhtyrCube.transform.localPosition = new Vector3(-8.52f, 5.37f, -0.92f);

Modified Eikthyr Location

Creating copies of existing locations

Use ZoneManager.Instance.CreateClonedLocation to clone a location. The cloned location is automatically added.

CustomLocation myEikthyrLocation = ZoneManager.Instance.CreateClonedLocation("MyEikthyrAltar", "Eikthyrnir");
myEikthyrLocation.ZoneLocation.m_exteriorRadius = 1f; // Easy to place :D
myEikthyrLocation.ZoneLocation.m_quantity = 20; //MOAR

Creating empty Location containers

To create new locations in code, use the ZoneManager.Instance.CreateLocationContainer. This will create a GameObject that is attached to a disabled internal container GameObject. This means you can instantiate prefabs without enabling them immediately. It only creates the container, it still needs to be registered with ZoneManager.Instance.AddCustomLocation

GameObject cubesLocation = ZoneManager.Instance.CreateLocationContainer("lulzcube_location");

// Stack of lulzcubes to easily spot the instances
for (int i = 0; i < 10; i++)
{
    var lulzCube = Instantiate(lulzCubePrefab, cubesLocation.transform);
    lulzCube.transform.localPosition = new Vector3(0, i + 3, 0);
    lulzCube.transform.localRotation = Quaternion.Euler(0, i * 30, 0);
}

ZoneManager.Instance.AddCustomLocation(new CustomLocation(cubesLocation, new LocationConfig
{
    Biome = Heightmap.Biome.Meadows,
    Quantity = 5,
    Priotized = true,
    ExteriorRadius = 2f,
    ClearArea = true,
}));

Creating locations from AssetBundles

You can also create your locations in Unity, it should have a Location component.

You can use JVLmock_<prefab_name> GameObjects to reference vanilla prefabs in your location by adding an optional true to the CreateLocationContainer constructor. You can have multiple instances of the same JVLmock_<prefab> (<number>), these will all be replaced by the prefab.

var cubeArchLocation = ZoneManager.Instance.CreateLocationContainer(locationsAssetBundle.LoadAsset<GameObject>("CubeArchLocation"), true);
ZoneManager.Instance.AddCustomLocation(new CustomLocation(cubeArchLocation, new LocationConfig
{
    Biome = Heightmap.Biome.BlackForest,
    Quantity = 200,
    Priotized = true,
    ExteriorRadius = 2f,
    MinAltitude = 1f,
    ClearArea = true,
}));

Vegetation

Jötunn uses the VegetationConfig together with CustomVegetation to define new Vegetation that will be injected into the world generation.

Modifying existing vegetation

Modify existing Vegetation configuration to increase the group size:

var raspberryBush = ZoneManager.Instance.GetZoneVegetation("RaspberryBush");
raspberryBush.m_groupSizeMin = 10;
raspberryBush.m_groupSizeMax = 30;

Adding vegetation

Any prefab can be added as vegetation:

CustomVegetation customVegetation = new CustomVegetation(lulzCubePrefab, new VegetationConfig
{
    Biome = Heightmap.Biome.Meadows,
    BlockCheck = true
});

This example defines very little filters, so this prefab will be found all over every Meadows.

Lulzcube vegetation