Lessons Learned Prototyping in Unreal Editor for Fortnite (UEFN)

Graham Haphey
Robert Kavert

Last year, Gamebreaking Studios used Unity to create a gameplay prototype for an internal game titled "Down to Crown". This asymmetric party game combines aspects of keep-away with king-of-the-hill. Players fight over control of "The Crown," which has the power to transform a player into a giant monster. It took 2 engineers a few months to get a somewhat polished version of the prototype in Unity. A few weeks ago, we had the thought experiment…

Would we have saved time if we prototyped the game using Unreal Editor for Fortnite (UEFN) instead of Unity?

What is UEFN

UEFN, a project by Epic Games, offers a unique opportunity for content creators to design custom games and brand experiences within the Fortnite platform, akin to Roblox and other user-generated content (UGC) platforms. This relatively new space provides a fresh avenue for idea exploration. We allocated approximately 2 weeks for familiarization and 2 weeks for implementation. We hypothesized that completing the prototype within this timeframe would demonstrate UEFN's potential as a time-saving alternative to prototyping in Unity.

Some Hurdles

Our initial hurdle with UEFN was figuring out how to enable player control of a giant monster. The Fortnite Character object within the editor is tightly controlled, prohibiting changes to scale or model. This necessitated some creative problem-solving: we first had to conceal the character model (which was supported), then overlay a larger model with different animations over the invisible Fortnite character. By having the large model mimic the movements of the invisible model, we could simulate the control of the larger character.

Using mutators and damage zones, we created the other desired behaviors, and trigger devices could be used as functionality splitters for quick iteration. We used a trigger device as a Verse event function caller; we created a custom verse editable trigger device that the editor could reference to bind Actors to functionality at runtime. Once the device was referenced, objects in the world (like the camera modifier and movement speed changes for the monster) could be triggered from Verse code despite function bindings for that functionality not being accessible.


Our experience using Verse was an interesting journey. The flexible syntax presented some initial frustration, as other languages typically have more rigidity. Moving fast in any language comes with known caveats: lower reliability and reduced extensibility. UEFN operates using Verse Devices, and while you can create your own devices for custom behavior, you still must use Epic's provided devices to tap into game events. Devices, by default, do not have access to things like game mode or states, and you have to use other pre-made devices to pass these signals around to create systems. The result feels like a daisy chain of editor-placed objects (called devices) pieced together for the specific behaviors you need to create custom gameplay. Very different from building a game from scratch.

Toolsets & Source Control

Some toolsets, including the source control solution, still need quality-of-life improvements. While Perforce and the UEFN integration struggle to merge binary files, such as serialized actors, the UEFN editor benefits from inventive source control patterns like checking in Verse data changes before logic to support them comes online. This was a minor time sink, but devoting resources to custom processes distracts from the activity of making game content.

Map Scale

Prototyping a game initially built in a traditional game engine provided some interesting obstacles. Translating the scale and environment into Fortnite required multiple iterations to help capture our desired game feel. Down to Crown's design had a chaotic, tight movement around a small map; Fortnite, however, has a huge map by default along with many movement options; this required us to scale down our environment quite a bit to achieve that chaotic party game feel. The default camera angle for the Fortnite character presented challenges for the player who had control of the monster, so it required a lot of tweaking to get right.

The Outcomes

The outcome of our experiment was a successful release! You can play "Down to Crown" within Fortnite today!

Island Code:

Key Takeaways

  • Due to the learning curve and overcoming some obstacles, prototyping did take longer than anticipated, but we still managed to deliver the game we envisioned.
  • Exploring the UEFN space was intriguing and could offer significant value in rapid prototyping, particularly for concepts with third-person shooter controls.
  • A key advantage of UEFN is its ready-to-use multiplayer platform with an existing player base, making it an obvious choice for prototyping online games.
  • Although you could potentially reach a wider audience using the Fortnite platform, party games or concepts outside the third-person shooter realm may require more effort. There's also the possibility of engaging with brands to create player-engaging experiences within Fortnite.

Lets Chat!

We hope our experience has helped you learn more about UEFN. Don't hesitate to contact us to discuss developing games for UEFN, consulting, or game co-development projects.