lock_device: Pirate Vault Doors That Open on Cue

Overview

The lock_device wraps any UEFN door asset and exposes six methods that cover every state transition a door can have:

• Lock / Unlock / ToggleLocked — control whether the door can be opened by a player.
• Open / Close / ToggleOpened — physically swing the door regardless of lock state (useful for scripted cinematics or auto-doors).

Reach for lock_device whenever you need scripted door control: a vault that opens only after a puzzle is solved, a jail cell that slams shut when a player enters, a treasure room that unlocks after all enemies are defeated, or an auto-sliding door triggered by proximity.

Important: lock_device only works with props/assets that have a door component attached. A plain static mesh will not respond.

API Reference

lock_device

Used to customize the state and accessibility of doors. lock_device only works with assets that have a door attached.

Full public surface, resolved verbatim from the live Epic digest (Fortnite.digest.verse).

lock_device<public> := class<concrete><final>(creative_device_base):

Methods (call these to make the device act):

trigger_device

Used to relay events to other linked devices.

Full public surface, resolved verbatim from the live Epic digest (Fortnite.digest.verse). Inherited members are merged from trigger_base_device.

trigger_device<public> := class<concrete><final>(trigger_base_device):

Events (subscribe a handler to react):

Methods (call these to make the device act):

hud_message_device

Used to show custom HUD messages to one or more agents.

Full public surface, resolved verbatim from the live Epic digest (Fortnite.digest.verse).

hud_message_device<public> := class<concrete><final>(creative_device_base):

Events (subscribe a handler to react):

Methods (call these to make the device act):

player

Full public surface, resolved verbatim from the live Epic digest (Verse.digest.verse). Inherited members are merged from agent.

player<native><public> := class<unique><persistent><module_scoped_var_weak_map_key><epic_internal>(agent):

Walkthrough

The Scenario

A cel-shaded pirate cove. A heavy vault door blocks the treasure room. Two pressure-plate triggers are hidden on the dock — both must be stepped on (in any order) before the vault unlocks and swings open. A HUD message guides the player through each step.

Level Setup

1. Place a lock_device on your vault door asset. In its Details panel set Starts Locked = true, Starts Open = false.
2. Place two trigger_devices (PlateA and PlateB) as pressure plates on the dock. Set Trigger Activation = Player, Max Trigger Count = 1 each.
3. Place a hud_message_device (HUD). Set Display Time = 3.0 s, Target = Triggering Player.

The Code

using { /Fortnite.com/Devices }
using { /Verse.org/Simulation }

# Localised message helper — Verse requires `message` not raw strings
PirateHint<localizes>(S : string) : message = "{S}"

pirate_vault_device := class(creative_device):

    # ── Editable device references ──────────────────────────────────────
    @editable VaultDoor   : lock_device        = lock_device{}
    @editable PlateA      : trigger_device     = trigger_device{}
    @editable PlateB      : trigger_device     = trigger_device{}
    @editable HUD         : hud_message_device = hud_message_device{}

    # ── Internal state ───────────────────────────────────────────────────
    var PlateATriggered : logic = false
    var PlateBTriggered : logic = false

    # ── Lifecycle ────────────────────────────────────────────────────────
    OnBegin<override>()<suspends> : void =
        # Subscribe to both pressure plates
        PlateA.TriggeredEvent.Subscribe(OnPlateATriggered)
        PlateB.TriggeredEvent.Subscribe(OnPlateBTriggered)

        # Greet the first player to load in (broadcast version — no agent)
        HUD.Show(PirateHint("Find the two hidden dock plates to open the vault!"))

    # ── Plate A handler ──────────────────────────────────────────────────
    OnPlateATriggered(MaybeAgent : ?agent) : void =
        if (A := MaybeAgent?):
            set PlateATriggered = true
            HUD.Show(A, PirateHint("Plate A — activated! Find the second plate."))
            CheckVaultCondition(A)

    # ── Plate B handler ──────────────────────────────────────────────────
    OnPlateBTriggered(MaybeAgent : ?agent) : void =
        if (A := MaybeAgent?):
            set PlateBTriggered = true
            HUD.Show(A, PirateHint("Plate B — activated! Find the second plate."))
            CheckVaultCondition(A)

    # ── Vault logic ──────────────────────────────────────────────────────
    CheckVaultCondition(Agent : agent) : void =
        if (PlateATriggered? and PlateBTriggered?):
            # Both plates pressed — unlock then open the vault door
            VaultDoor.Unlock(Agent)
            VaultDoor.Open(Agent)
            HUD.Show(Agent, PirateHint("The vault is open — claim your treasure!"))

Line-by-Line Explanation

Common patterns

Pattern 1 — Toggle a jail cell door when a player re-enters a trigger

A guard shack trigger toggles the cell open/closed each time it fires — great for a repeating patrol mechanic.

using { /Fortnite.com/Devices }
using { /Verse.org/Simulation }

CellHint<localizes>(S : string) : message = "{S}"

jail_toggle_device := class(creative_device):

    @editable CellDoor    : lock_device        = lock_device{}
    @editable GuardTrigger: trigger_device     = trigger_device{}
    @editable HUD         : hud_message_device = hud_message_device{}

    OnBegin<override>()<suspends> : void =
        GuardTrigger.TriggeredEvent.Subscribe(OnGuardTriggered)

    OnGuardTriggered(MaybeAgent : ?agent) : void =
        if (A := MaybeAgent?):
            # ToggleOpened swings the door open if closed, or closed if open
            CellDoor.ToggleOpened(A)
            HUD.Show(A, CellHint("The cell door shifts..."))

Key call: ToggleOpened(Agent) — one call handles both directions, no extra state variable needed.

Pattern 2 — Lock a door after a player passes through (one-way gate)

A clifftop gate lets a player through, then locks behind them so they cannot backtrack.

using { /Fortnite.com/Devices }
using { /Verse.org/Simulation }

GateHint<localizes>(S : string) : message = "{S}"

one_way_gate_device := class(creative_device):

    @editable CliffGate    : lock_device        = lock_device{}
    @editable PassTrigger  : trigger_device     = trigger_device{}
    @editable HUD          : hud_message_device = hud_message_device{}

    OnBegin<override>()<suspends> : void =
        # Allow only one pass — after that the trigger disables itself
        PassTrigger.SetMaxTriggerCount(1)
        PassTrigger.TriggeredEvent.Subscribe(OnPlayerPassed)

    OnPlayerPassed(MaybeAgent : ?agent) : void =
        if (A := MaybeAgent?):
            CliffGate.Open(A)
            # Brief pause so the player can walk through
            Sleep(1.5)
            CliffGate.Close(A)
            CliffGate.Lock(A)
            HUD.Show(A, GateHint("The gate locks behind you. No turning back!"))

Key calls: Open → Sleep → Close → Lock — a sequential async chain inside a <suspends> context. SetMaxTriggerCount(1) ensures the trigger fires exactly once.

Pattern 3 — HUD countdown then auto-close a treasure room

After the vault opens, a timed HUD message warns the player, then the door slams shut automatically.

using { /Fortnite.com/Devices }
using { /Verse.org/Simulation }

TimerHint<localizes>(S : string) : message = "{S}"

treasure_timer_device := class(creative_device):

    @editable TreasureDoor  : lock_device        = lock_device{}
    @editable EnterTrigger  : trigger_device     = trigger_device{}
    @editable HUD           : hud_message_device = hud_message_device{}

    OnBegin<override>()<suspends> : void =
        EnterTrigger.SetMaxTriggerCount(1)
        EnterTrigger.TriggeredEvent.Subscribe(OnEnterTreasure)

    OnEnterTreasure(MaybeAgent : ?agent) : void =
        if (A := MaybeAgent?):
            TreasureDoor.Unlock(A)
            TreasureDoor.Open(A)
            # Show a persistent warning (DisplayTime 0.0 = persistent)
            HUD.Show(A, TimerHint("You have 10 seconds before the vault seals!"), ?DisplayTime := 0.0)
            Sleep(10.0)
            HUD.Hide(A)
            TreasureDoor.Close(A)
            TreasureDoor.Lock(A)
            HUD.Show(A, TimerHint("The vault has sealed. Escape with your loot!"))

Key calls: HUD.Show(Agent, Message, ?DisplayTime := 0.0) for a persistent message, HUD.Hide(Agent) to clear it, then Close + Lock to seal the room.

Gotchas

1. Lock and Open are independent states

Lock/Unlock controls accessibility; Open/Close controls physical position. A door can be locked AND open at the same time (it stays open but a player cannot close it). Always call Unlock before Open if you want the player to be able to interact with it afterward.

2. ?agent must be unwrapped before use

TriggeredEvent sends ?agent (an optional). Passing it directly to VaultDoor.Unlock(MaybeAgent) is a compile error because the method expects agent, not ?agent. Always unwrap:

if (A := MaybeAgent?):
    VaultDoor.Unlock(A)

3. message is not a plain string

Every hud_message_device method that takes text expects the message type, not a string. Declare a localizer helper at module scope:

MyText<localizes>(S : string) : message = "{S}"

There is no StringToMessage function — the <localizes> specifier is the only way.

4. lock_device needs a door asset

The device silently does nothing if attached to a plain static mesh. In UEFN, choose a prop from the Content Browser that has a door component (look for assets tagged Door in the Creative prop library).

5. Sequential async calls require <suspends>

Chaining Open → Sleep → Close only works inside a function marked <suspends> (like OnBegin) or a spawned coroutine. Event handler methods are not <suspends> by default — if you need async behaviour inside a handler, spawn a helper:

OnPlateTriggered(MaybeAgent : ?agent) : void =
    if (A := MaybeAgent?):
        spawn { RunDoorSequence(A) }

RunDoorSequence(Agent : agent)<suspends> : void =
    VaultDoor.Open(Agent)
    Sleep(5.0)
    VaultDoor.Close(Agent)
    VaultDoor.Lock(Agent)

6. SetMaxTriggerCount clamps to [0, 20]

Passing a value outside that range is silently clamped. Use 0 for unlimited triggers.