The Ghost Protocol: Building Invisible Traps with Prop Manipulators

You know that feeling when you’re playing a Creative map, and you walk into a room that looks completely empty, only to get shotgunned by a chair that wasn’t there a second ago? That’s not magic. That’s the Prop Manipulator device doing its job.

In this tutorial, we’re going to build a "Ghost Room." It’s a simple arena where you start with nothing, but as soon as you step on a pressure plate, invisible walls and floors slam into existence around you, trapping you in a cage of geometry. No code required—just straight-up UEFN logic. We’ll learn how to control visibility and health on a group of objects, which is the superpower of the Prop Manipulator.

What You'll Learn

• What a Prop Manipulator is: The device that acts as a remote control for the health and visibility of props.
• Volumes: How to define an area in 3D space to target specific objects.
• Visibility vs. Health: The difference between hiding a prop and making it indestructible.
• Event Wiring: Connecting a trigger to the manipulator so things happen when you interact.

How It Works

Think of the Prop Manipulator like the Battle Bus driver for props. Normally, props just sit there. But when you add a Prop Manipulator, you give it the ability to send those props "in" or "out" of the game (visibility) or buff their durability (health).

Here is the breakdown of the mechanics we are using:

1. The Volume (The "Zone"): In Fortnite, you have storm circles or capture zones. A Volume is just a 3D box you draw in the editor. The Prop Manipulator only cares about props inside this box. If a prop is outside, the device ignores it.
2. Visibility (Invisible Man): This option toggles whether the prop is rendered on screen. If set to "Hidden," the prop is still there physically (you can walk into it if it has collision), but you can’t see it. This is perfect for traps.
3. Health (Tank Mode): This sets how much damage a prop can take before breaking. If you set a glass pane’s health to 9999, it becomes unbreakable. If you set it to 0, it might not even spawn, depending on the game mode. We’ll use this to make our trap walls solid.
4. Events (The Trigger): Just like a button needs to be pressed to open a door, our Prop Manipulator needs an "Event" to know when to change the props. We’ll use a Player Spawner or a Trigger Volume to say "Hey, someone entered! Activate the trap!"

One device, two states: a trigger flips Inactive (props visible) to Active (props hidden) — no code needed.

Let's Build It

We are building a Ghost Trap.

• Goal: Walk into a room. The floor disappears, and invisible walls close in. You have to find a hidden exit button to escape.
• Devices Needed:
  • 1x Prop Manipulator
  • 1x Trigger Volume (or a simple Button)
  • Several Props (Walls, Floors, maybe a decorative chair for chaos)

Step 1: Set the Stage

Build a small 5x5 room. Place a few props inside: some walls, a table, maybe a random trash can. We want these to be visible at the start.

Step 2: Add the Prop Manipulator

1. Open the Devices menu.
2. Search for Prop Manipulator.
3. Place it anywhere in the map. It doesn’t matter where, because it controls props via its Volume, not its physical location.

Step 3: Define the Volume

1. Select the Prop Manipulator.
2. Look at the Details Panel (the properties on the right).
3. Find the Volume section. You’ll see a box outline.
4. Drag the corners of this box so it encompasses all the props you want to manipulate (the walls, the floor, the trash can).
   • Pro Tip: If you select the props in the World Outliner while the Manipulator is active, it often auto-fits the volume to them. Use that!

Step 4: Configure the Props

In the Prop Manipulator’s Details Panel, you’ll see options for Visibility and Health.

• Visibility: Set this to Hidden. Now, when the device is "active," these props will vanish.
• Health: Let’s leave this alone for now, or set it to a high number if you want them to be indestructible when they reappear.

Wait, if we hide them now, we can’t see what we’re doing! Actually, the Prop Manipulator has a State. By default, it’s usually "Inactive." We need to wire it up so it only hides things when we want it to.

Step 5: Wire the Trigger

We need a way to tell the Prop Manipulator: "Hide the props!"

1. Place a Trigger Volume in the center of your room. Make it small enough that you have to step past the threshold to trigger it.
2. Select the Trigger Volume.
3. In the Details Panel, find the Events section.
4. Look for On Begin Play or On Player Enters. Let’s use On Player Enters.
5. Click the "+" next to On Player Enters to add an output.
6. Drag a wire from the Trigger Volume’s On Player Enters output to the Prop Manipulator’s Activate input.

Step 6: The "Ghost" Logic

There’s a catch. If we just activate it, the props hide. But how do we make them come back? Or do we want them to stay hidden? For a "Ghost Trap," let’s make it so:

1. You enter -> Props Hide (You are now in a void).
2. You hit a hidden button -> Props Reappear (You are trapped).

To do this, we need two Prop Manipulators or one that toggles. Actually, the simplest way for a beginner is to use Two States:

• State 1 (Start): Props are Visible.
• State 2 (Trap): Props are Hidden.

The Prop Manipulator has a Current State property.

1. Select the Prop Manipulator.
2. In the Details, find Start State. Set it to Active.
3. Wait, if it starts active, the props are hidden immediately. That’s not what we want.
4. Let’s flip the logic. Set Start State to Inactive.
5. In the Inactive State settings, set Visibility to Visible.
6. In the Active State settings, set Visibility to Hidden.

Now, wire the Trigger Volume’s On Player Enters to the Prop Manipulator’s Activate.

• When you enter, the device activates.
• The device switches to "Active State."
• "Active State" says "Hide Visibility."
• POOF! The props vanish. You are alone in the dark.

Step 7: The Escape (Optional Chaos)

To make it a real game, add a Button somewhere in the empty space.

1. Place a Button.
2. Wire the Button’s On Interact to the Prop Manipulator’s Deactivate.
3. Now, when you hit the button, the device goes back to "Inactive State."
4. "Inactive State" says "Show Visibility."
5. POOF! The props reappear. If they are walls around you, you’re now trapped in a box of geometry.

The Code? None.

You just used the Prop Manipulator’s built-in state machine. No Verse code needed for this basic version. But if you wanted to get fancy, you could use Verse to change the Health dynamically based on a score. For now, master the Volume and the State.

Try It Yourself

Challenge: Create a "Loot Goblin" room.

• Goal: When a player enters, invisible loot crates appear in random spots. When they pick up the loot, the crates disappear.
• Hint: You’ll need to use the Health property of the Prop Manipulator instead of Visibility. Set the crates to "Hidden" in the Inactive State. When the player picks up the item (use an Item Granter or Pickup event), activate the Prop Manipulator to make the crates visible. Then, use a Timer or Prop Breaker event to hide them again once they’re broken.

Recap

The Prop Manipulator is your remote control for props. By defining a Volume, you tell it which props to watch. By setting Visibility and Health in different States, you control whether they show up and how tough they are. Wire it to a trigger, and you’ve got a dynamic, interactive environment without writing a single line of code.

References

• https://dev.epicgames.com/documentation/en-us/fortnite-creative/using-prop-manipulator-devices-in-fortnite-creative
• https://dev.epicgames.com/documentation/en-us/fortnite/using-prop-manipulator-devices-in-fortnite-creative
• https://dev.epicgames.com/documentation/en-us/fortnite-creative/using-devices-in-fortnite-creative
• https://dev.epicgames.com/documentation/en-us/fortnite/prop-manipulator-device-design-examples-in-fortnite
• https://dev.epicgames.com/documentation/en-us/fortnite/cinematic-sequenceples-in-fortnite