The Ultimate Speed Bump: Mastering RR EMP Volumes in UEFN

So you’ve built the track. You’ve placed the boosts. You’ve made sure the finish line isn’t just a random wall of dirt. But your race feels too easy. Everyone zips through like they’re on a magic carpet, and there’s no tension, no "wait, how did I lose?" moment. That’s where the RR EMP Volume comes in. It’s the digital equivalent of hitting a patch of ice or getting hit by a stray shockwave—sudden, frustrating, and perfectly balanced to keep players on their toes.

In this tutorial, we’re going to turn your smooth-sailing Rocket Racing track into a high-stakes obstacle course using the RR EMP Volume device. No complex coding required—just pure, unadulterated track chaos.

What You'll Learn

• What an RR EMP Volume is and why it’s the ultimate "oops" device for racers.
• How to place and shape these volumes to create tricky zones without breaking the game.
• Why you can’t tweak the amount of slowdown (and why that’s actually a good thing).
• How to combine EMP zones with boosts for a satisfying "push-pull" gameplay loop.

How It Works

Think of the RR EMP Volume as a "speed trap" zone. In Fortnite Creative, you’ve probably used generic volume devices to trigger events. In Rocket Racing, specific devices are built into the engine to handle vehicle physics directly.

Here’s the deal: When a vehicle drives over an RR EMP Volume, its speed is instantly reduced. It’s not a crash, and it’s not an elimination (unless you hit a different hazard). It’s just a hiccup. Your car slows down, giving the player behind you a chance to catch up, or forcing the leader to make a mistake.

The "Black Box" Rule

There is one major catch: You cannot edit the strength or duration of the slowdown.

Why? Because Epic wants consistency. If you could make one EMP zone slow cars by 10% and another by 90%, players would get confused. Is the track broken? Or is it just a hard zone? By keeping the slowdown fixed, every EMP volume feels fair. You’re not the mechanic fixing the car; you’re the track designer placing the traps.

Shaping Your Trap

While you can’t change how hard it slows you down, you can change where it hits. You can stretch, squash, and rotate the volume. This is your creative playground. Want a wide, sweeping curve that slows everyone down? Done. Want a tiny, needle-thin strip across the finish line that only catches the leader by a millimeter? Also done.

Let's Build It

We’re going to build a simple "Speed Trap" zone at the end of a straightaway. Imagine a long, fast straight. At the very end, just before a sharp turn, we’ll place an EMP volume. If the player doesn’t brake in time, they’ll get blasted with the slowdown right as they try to corner, sending them wide or spinning out.

Step 1: Find the Device

1. Open your Rocket Racing island template in UEFN.
2. Open the Devices panel (usually on the left).
3. Search for "RR EMP Volume". It’s under the Rocket Racing category.

Step 2: Place the Volume

1. Drag the RR EMP Volume device into your scene.
2. Place it on the track where you want the slowdown to happen. For our example, let’s put it right before a tight hairpin turn.

Step 3: Shape the Trap

This is the most important part. By default, it’s a cube. That’s boring.

1. Select the device in the viewport.
2. Use the Transform Tools (Move, Rotate, Scale) to shape it.
   • Scale: Stretch it along the track to make a long "wall" of slowdown, or shrink it to a tiny "speed bump."
   • Rotate: If your track curves, rotate the volume to match the flow. You want the vehicle to pass through it, not just clip a corner.
   • Height: Make sure it’s tall enough to catch the vehicle, but not so tall that it looks like a floating ceiling. Usually, keeping it low and wide works best for ground-based slowdowns.

Step 4: Test It

1. Hit Play.
2. Drive a vehicle through the zone.
3. Feel the drag. Did it feel fair? Did it punish bad driving? If it’s too easy to avoid, shrink the volume. If it feels like a wall, make it smaller or move it.

Step 5: Combine with Boosts (The "Push-Pull" Loop)

Now, let’s make it interesting. Place an RR Boost Pad immediately after the EMP Volume.

1. Drive through the EMP: You slow down.
2. Drive through the Boost: You speed back up. This creates a rhythm. Players have to modulate their speed—brake for the EMP, then hit the gas for the boost. It’s a skill check disguised as a speed trap.

Try It Yourself

Challenge: Create a "Gauntlet of Slowdowns."

Place three RR EMP Volumes in a row, but shape them differently:

1. The first one should be a wide, flat strip that slows everyone equally.
2. The second one should be a narrow, tall pillar that only slows vehicles that are off-center.
3. The third one should be a long, thin line that runs across the entire track width, forcing a full stop.

Hint: Think about how vehicles drive. Do they hug the inside of turns? Do they drift? Place your volumes where players naturally want to go, so they can’t just avoid them by driving on the grass.

Recap

• RR EMP Volumes are dedicated devices for slowing down vehicles in Rocket Racing islands.
• You cannot edit the slowdown strength or duration—this ensures fair, consistent gameplay.
• You can edit the shape, size, and position of the volume, which is where your creativity shines.
• Use them to create tension, punish mistakes, and create rhythmic gameplay loops with boosts.

Now go out there and make your players scream (in a good way).

References

• https://dev.epicgames.com/documentation/en-us/fortnite/using-rocket-racing-emp-volume-devices-in-unreal-editor-for-fortnite
• https://dev.epicgames.com/documentation/en-us/fortnite-creative/using-devices-in-fortnite-creative
• https://dev.epicgames.com/documentation/en-us/uefn/using-rocket-racing-emp-volume-devices-in-unreal-editor-for-fortnite
• https://dev.epicgames.com/documentation/en-us/uefn/working-with-rocket-racing-islands-in-unreal-editor-for-fortnite
• https://dev.epicgames.com/documentation/en-us/fortnite/using-rocket-racing-devices-in-unreal-editor-for-fortnite