Spawning

In single-player, instantiating a scene creates a local node. In multiplayer, the same operation must create that node on every connected client and assign it a network identity so the replication system can track it. This is what networked spawning does - it turns a local scene instantiation into a coordinated event across all peers.

Despawning is the reverse: it removes the object from every client and frees its network identity. Late-joining clients automatically receive the current set of spawned objects when they enter the room.

Setup

FusionSpawner acts as a networked factory that creates and destroys objects across all clients. Add a FusionSpawner node to your scene and register spawnable scenes:

GDScript

const PlayerScene = preload("res://player.tscn")
const ProjectileScene = preload("res://projectile.tscn")

@onready var spawner = $FusionSpawner

func _ready():
    spawner.add_spawnable_scene(PlayerScene)
    spawner.add_spawnable_scene(ProjectileScene)
    spawner.spawned.connect(func(n): print("Spawned: ", n.name))
    spawner.despawned.connect(func(n): print("Despawned: ", n.name))

Set spawn_path to the parent node for spawned objects (default: spawner's parent).

Spawn and Despawn

Call spawn() to create a networked instance and despawn() to remove it from all clients.

GDScript

# Spawn first registered scene
var player = spawner.spawn()
player.position = Vector2(100, 200)

# Spawn a specific registered scene
var projectile = spawner.spawn(ProjectileScene)

# Despawn
spawner.despawn(player)

Set properties on the returned node after spawning. Replicated properties (configured in FusionReplicationConfig) will be included in the next network update.

Scene Structure

A typical game scene has a FusionSpawner alongside any game logic, while each spawnable scene has its own FusionReplicator as a child of the root node.

Properties

These properties configure where spawned objects are placed in the tree and which scenes are available.

• spawn_path (NodePath, "..") - parent for spawned objects
• spawnable_scenes (Array[PackedScene]) - registered spawnable scenes

Signals

FusionSpawner emits signals when objects are created or destroyed, on all clients.

• spawned(node: Node) - object spawned (local or remote)
• despawned(node: Node) - object despawned

Sub-Objects

Sub-objects are dynamic children attached to a spawned root that get their own sync buffer. They share the root's authority - the same client owns both parent and sub-object.

To spawn sub-objects, add a FusionSpawner as a child of a spawned scene and call bind_root_replicator() to link it to the parent's replicator. This makes the spawner a "sub-spawner" - its spawn() calls create sub-objects instead of root objects.

GDScript

# In the spawned scene's script:
const TurretScene = preload("res://turret.tscn")

@onready var sub_spawner: FusionSpawner = $SubSpawner

func _ready():
    sub_spawner.add_spawnable_scene(TurretScene)
    sub_spawner.bind_root_replicator($FusionReplicator)

func spawn_turret():
    var turret = sub_spawner.spawn(TurretScene)
    turret.position = Vector2(0, -20)

Sub-objects must have their own FusionReplicator.