Registering custom prefabs

Prefabs in Valheim are objects that can be instantiated and used within the world. This includes everything from inventory items, placeable items (Pieces), entities, etc.

Note: In order to create Pieces, Inventory items, Vegetation, or nearly anything, it must have a prefab created first.

Creation/management of prefabs is done through the PrefabManager singleton class.

Prefabs can be created by creating a handler within your mod's Awake function for the PrefabRegister event.

Note that prefabs are configured to be persistent by default, so if placed (as a piece or dropped) they'll be saved with your world. If you wish to change that behaviour, modify the ZNetView component on the prefab and set m_persistent = false.

Existing prefabs

For a list of all existing in-game prefabs, check this page. The prefab names are the same as their names when using the spawn console command.

Example

In order to create a prefab, there's a couple different approaches:

• PrefabConfig approach: using a PrefabConfig to hold our Prefab info
• CreatePrefab approach: Using the CreatePrefab functions

Below we'll look at both ways of creating the exact same prefab. You'll notice that the functional approach may look neater, however, it gets unwieldy fairly quickly when you register many prefabs within the same file - hence the PrefabConfig approach is recommended.

PrefabConfig approach

First, creating our prefab class that inherits from PrefabConfig. We need to then implement a default constructor, as well as the void Register() method.

Within our constructor, we can call the base constructor with either one or two arguments:

• base(String ourPrefabName): Creating an empty prefab with no base object
• base(String ourPrefabName, String baseName): Creating a prefab that's a copy of the base

Next, we can implement our void Register() method. In here, we can make any changes we need to the prefab, such as adding components or modifying existing components.

To do this, we can use the member variable Prefab that's of type GameObject. This is set for us after our constructor is called. If we're inheriting an existing prefab, Prefab will be a copy of what we've inherited. Otherwise, it'll be an empty GameObject.

public class TestPrefab : PrefabConfig
{
    public TestPrefab() : base("TestPrefab", "Wood")
    {
        // Nothing to do here
        // "Prefab" wil be set for us automatically after this is called
    }

    public override void Register()
    {
        // Configure item drop
        // ItemDrop is a component on GameObjects which determines info about the item when it's picked up in the inventory
        ItemDrop item = Prefab.GetComponent<ItemDrop>();
        item.m_itemData.m_shared.m_name = "Test Prefab";
        item.m_itemData.m_shared.m_description = "We're using this as a test";
        item.m_itemData.m_dropPrefab = Prefab;
        item.m_itemData.m_shared.m_weight = 1f;
        item.m_itemData.m_shared.m_maxStackSize = 1;
        item.m_itemData.m_shared.m_variants = 1;
    }
}

Next, creating a handler for PrefabRegister

private void Awake()
{
    // Register our handler
    PrefabManager.Instance.PrefabRegister += registerPrefabs;
}

private void registerPrefabs(object sender, EventArgs e)
{
    // Create a new instance of our TestPrefab
    PrefabManager.Instance.RegisterPrefab(new TestPrefab());
}

CreatePrefab approach

First, creating a handler for PrefabRegister

private void Awake()
{
    // Register our handler
    PrefabManager.Instance.PrefabRegister += registerPrefabs;
}

private void registerPrefabs(object sender, EventArgs e)
{
   // Prefab init code goes here 
}

Next, we need to actually create our prefab game object

private void registerPrefabs(object sender, EventArgs e)
{
    // Prefab init code goes here
    GameObject prefab = PrefabManager.Instance.CreatePrefab("TestPrefab", "Wood");

    ItemDrop item = prefab.GetComponent<ItemDrop>();
    item.m_itemData.m_shared.m_name = "Test Prefab";
    item.m_itemData.m_shared.m_description = "We're using this as a test";
    item.m_itemData.m_dropPrefab = Prefab;
    item.m_itemData.m_shared.m_weight = 1f;
    item.m_itemData.m_shared.m_maxStackSize = 1;
    item.m_itemData.m_shared.m_variants = 1;
}

Our prefab in game

That's it!
Now if we go in-game and type spawn TestPrefab in our console, it'll spawn what looks to be a piece of wood on the ground. In fact, this is the item we've just created! It however looks like a piece of wood since we copied the existing Wood prefab, and did not change its model.