The "Don't Get Deleted" Cave: Building Hidden Bases in UEFN

So, you want to build a secret lair, a dungeon, or just a place to hide from the storm without getting kicked out of the lobby. In standard Fortnite Creative, if you walk into a rock, you hit a wall. In UEFN, if you walk into a rock, you might get despawned (teleported back to the start) or your vehicle might glitch out and launch into the sky.

That’s because the game engine thinks you’re outside the playable world. To fix this, we need to carve a "cave" using the Landscape Visibility tool and seal it with a Fort Underground Volume. Think of the Volume as a "safe zone" sticker that tells the game: "Hey, these players are still in the game, just in a dark, rocky place."

What You'll Learn

• How to use the Sculpt tools to dig into a mountain.
• Why the Fort Underground Volume is your best friend (and how to use it so you don’t get kicked).
• The difference between just digging a hole and making a playable space.

How It Works

The Problem: The "Outside" Trap

Imagine your island is a stage. If a player walks off the edge of the stage, the director yells "Cut!" and sends them back to the dressing room (respawn). In Fortnite, the "edge of the stage" is defined by the World Bounds. If you dig a tunnel into a mountain but don't tell the game that the tunnel is part of the stage, the game thinks the player has left the map.

The Solution: Visibility + Volume

We use two tools to solve this:

1. Landscape Visibility (The Chisel): This tool lets you hide parts of the terrain. It doesn’t delete the rock; it just makes it invisible. This is great for making caves, tunnels, and overhangs.
2. Fort Underground Volume (The Safe Zone Sticker): This is a special device. When a player enters this volume, the game stops trying to kick them out. It tells the engine, "Even though they are underground, they are still playing." Without this, players will vanish the moment they step into your dark cave.

Let's Build It

We’re going to build a simple "Treasure Cave." We’ll dig a tunnel into a mountain and place a volume so players can walk in, find a chest, and walk out without getting deleted.

Step 1: Prep Your Mountain

1. Open your project in Unreal Editor for Fortnite (UEFN).
2. Find a mountain or a large hill. If you don’t have one, place a large Prop (like a boulder) or use the Landscape tools to raise the terrain.
3. Decide where the entrance will be. Ground level is easiest for beginners.

Step 2: Carve the Cave (Visibility)

1. Select your Landscape tool or the terrain mesh.
2. Switch your tool mode to Sculpt.
3. In the toolbar, select Visibility.
   • Analogy: This is like putting a black marker over a part of the map. The rock is still there, but you can’t see it.
4. Paint over the area where you want the cave entrance. You’ll see the rock disappear.
5. Keep painting to carve out a tunnel. Use the brush size to make it wide enough for a player (and maybe a vehicle) to fit.

Step 3: Place the Safe Zone (Fort Underground Volume)

1. Open the Device palette (the box icon).
2. Search for Fort Underground Volume.
3. Drag it into your scene.
4. Position it: Place the volume inside the cave you just carved. Make sure it covers the entire tunnel and exit area.
   • Tip: You can resize the volume in the viewport to make sure it’s big enough. If the volume is too small, players will get kicked out halfway through the tunnel.
5. Settings: Usually, the default settings are fine. The volume automatically detects when players enter it and keeps them "alive" in the game world.

Step 4: Add Atmosphere (Optional but Cool)

1. Place some Lights inside the cave so it’s not pitch black.
2. Add a Loot Granter or a Chest at the end of the tunnel.
3. Test it! Play your island. Walk into the cave. If you disappear, your Fort Underground Volume is either missing or too small.

The Code? None Needed!

For this specific task, you don’t need Verse code. The Fort Underground Volume is a "device" that handles the logic for you. It’s like a pre-built trap that just works.

Try It Yourself

Challenge: Build a "Double-Decker Cave."

1. Create two separate tunnels, one above the other.
2. Place a Fort Underground Volume in each tunnel.
3. Add a Prop Mover (a moving platform) that takes players from the top tunnel to the bottom tunnel.
4. Hint: Make sure the Prop Mover’s path stays inside the volumes. If the player goes outside the volume while moving, they might get despawned mid-air!

Recap

• Use Landscape Visibility to hide terrain and create caves/tunnels.
• Use a Fort Underground Volume to keep players from getting despawned while underground.
• Always test your cave: if players vanish, check your volume size and placement.

References

• https://dev.epicgames.com/documentation/en-us/fortnite/making-a-cave-in-unreal-editor-for-fortnite
• https://dev.epicgames.com/documentation/en-us/fortnite/sdg-sustainable-cities-lesson-plan-in-fortnite-creative
• https://dev.epicgames.com/documentation/en-us/uefn/lava-cave-in-unreal-editor-for-fortnite
• https://dev.epicgames.com/documentation/en-us/fortnite/sustainable-stacks-lesson-plan-for-fortnite-creative
• https://dev.epicgames.com/documentation/en-us/fortnite-creative/lesson-plan-heatwave-hideout-in-fortnite-creative