Courtesy of Fallen Leaf S.A

Fort Solis uses Unreal Engine 5.2 to deliver an immersive martian experience

Brian Crecente
Fallen Leaf is an exciting new independent games developer based in Liverpool’s renowned Baltic Triangle. With decades of experience from some of the world’s top studios, Fallen Leaf is breaking new ground with its innovative technology and narrative-based storytelling.
Fort Solis tells the story of one night in a desolate Martian mining camp. Initially tasked with discovering what happened at the base and to the people who once operated it, players soon find themselves desperately trying to survive an encroaching storm and the night.

Early inspiration for the Epic MegaGrant recipient came from what seems at first to be two disparate places: The isolation born of the pandemic and John Carpenter’s masterful horror epic The Thing.

The team at Fallen Leaf Studio had an idea to create story experiences that could be consumed like binging a wonderful show on Netflix.

Teaming up with Black Drakkar Games, the two studios looked to Unreal Engine 5.2 to help empower their creation from early ideation through to building out a compelling landscape, the darkened tunnels and empty department offices of the game, co-creation of levels, and character rigging.

The result, they hope, is a game that delivers a level of immersion you would find in your favorite TV show, but with players in control of the pacing.

We spoke with some of the developers at Fallen Leaf Studio about the deep use of Unreal Engine 5.2 and how it helped the two studios bring to digital life the sort of experience they envisioned in the beginning of Fort Solis’ development.
Courtesy of Fallen Leaf S.A
How did Fallen Leaf come together as a studio and what are its defining goals?

James Tinsdale, Studio Director:
Fallen Leaf came together out of a desire to create story experiences. Our previous history had been in mostly AAA games, and we wanted to look at creating smaller more detailed experiences that we had been consuming on TV streaming platforms.

This created a focus for our defining goals to create story experiences told within the gaming format to create compelling narratives around beautiful and immersive settings. We wanted to work within a smaller team using the industry's leading technologies. 

Where did the idea for Fort Solis come from and how did it evolve?

The original idea for Solis came during the pandemic. Everyone had time at home during that moment and I spent most of mine consuming streaming platform content and games. The idea to merge the worlds closer, taking inspiration from both, allowed Fort Solis to become a reality.

There are many influences within the game, but I have always adored John Carpenter movies. The Thing is my all-time favorite movie and when creating my own work, you always retain that inspiration from those that influence you the most.

Beyond movies, it was more reflective of the real world and the current moment everyone was unified by. In a terrifying way, it opened our eyes to how vulnerable we are and how hostile the world we live in can be.

How did you come to work with Black Drakkar Games and what are they doing on the game?

Once we had a road map, script, and initial plan, we reached out through a personal connection to see if Black Drakkar would be interested in helping form a team to work with us.

Once we discussed the initial plan, how we would approach development, and what the game could be, I knew BDG were an amazing partner for us.

Now that we have reached the end of the project, I couldn’t have asked for a better partner.

What can you tell us about Fort Solis’ backstory and what players will be doing in the game?

Throughout the game there are a lot of materials providing context on the events leading up to when Jack arrives at the base. These materials aim to provide more empathy to the events, visibility, and develop the story further beyond the moment-to-moment gameplay.

We hope, combined with the events of the night of Fort Solis, that they create a full picture of what became of the base and its crew. The backstory helps serve the narrative element of our audiences’ expectations and we took a risk leaving some of our bigger reveals to these materials in hopes of rewarding players looking for the full picture.
Courtesy of Fallen Leaf S.A
Since this is set on Mars, will the game be set in the distant future with strong sci-fi elements, or is it a more grounded game in terms of the technology you’ll see and use?

The game is set in 2080. We wanted to be realistically far enough away that perhaps terraforming is possible however remain relatable. This is due to the fact we wanted to base everything in a very realistic relatable feel that allows the characters to belong in the world without logical conflict.

We decided early to move away from a hologram futuristic format and retain the gritty hands-on feel that engineering traditionally offers. This allowed for the natural feel of the world to align with the characters to tell a story that, whilst set on Mars, could fit any setting.

You’ve said that the game isn’t a horror title, but rather a psychological thriller. How did you use Unreal Engine to walk that fine line?

Unreal Engine allowed us to immediately have the tools to workshop concepts and scale. The tools on offer would normally take a large amount of time and resources to develop internally so having that starting platform really enabled us to release the experience that much quicker.

Once you're able to visualize a concept, create it in 3D, and play the experience, it allows for the idea to come across to the team much quicker and more accurately.

What sort of development tools did you rely on to create the sense of dread, isolation, and loneliness that powers the game’s suspense?

We knew that both our audio and VFX would play an important role in bringing the world to life as it does in most games. Using Niagara allowed us to replicate the tone and feel of a scene quite quickly to help move into a thriller realm.

One of the coolest elements of our exterior is our developing storm. This engulfs the base by the end of the game and the transitions and progression of the storm itself help visually show time moving forward.
What advice would you give game developers who are hoping to create the subtle feeling of fear that comes from a thriller, rather than an over-the-top jump scare horror game?

We placed a lot of experimentation into the unknown. When you allude to factors or elements that the player understands will progress along with the narrative, to then see it reflected on the actors performance, it creates an immersive element that allows the player to feel they are on the journey with them.

This moves the moment happening to Jack to happening to the player. This is an element of thrillers that can be really hard to establish in the earlier moments of the game. You need to make the player care deeply about the stakes when they become apparent. Without that engagement you lose that payoff.

Advice I would offer would be to create relatable characters that develop as a reaction to the story they are unraveling. Let it take a toll on them, their mental state, their physical state. Make everything culminate in that reveal at the end and the payoff will be layered enough that it resonates with players strongly.

Lighting can play a big role in creating the atmosphere for a game. Can you walk us through how you used Lumen to achieve your goals?

Mark Cushley, Art Director:
Fort Solis is created to be a thrilling, immersive, and sometimes claustrophobic experience so Lumen was a no brainer for us. The real-time global illumination and reflections create a greater sense of realism that helps put the player right there alongside Jack. Aside from the visual benefits, the new workflow, time savings, and level of creativity this allowed us was worth it alone.

We are now using a fully dynamic setup in Fort Solis; every single light in the game is moveable with no need to spend hours baking lightmaps or worrying about lightmap UVs. This I'm sure still has a place in game development but for us, this meant we had the ability to change lighting scenarios on the fly, dynamically move them during key sequences or have them be motion sensitive to the player input with Lumen updating the world around to reflect this.
Courtesy of Fallen Leaf S.A
How did you make use of Nanite and Megascan assets to create the look of Mars?

Although you do spend some time at another location, most of the game is set around the Fort Solis base. So our exploration of Mars is within a predefined area. Using Megascans and Nanite, we could afford to push the density and quality of the assets far beyond what we would if you were traversing miles and miles across an open-world landscape.

These assets were key for us in being able to sculpt and frame up a core cinematic experience, but this extends far beyond our Mars surface. At least 90 percent of all of the geometry in our game now uses Nanite. Whether walking down a tunnel or entering a vast open area, you should experience a level of world building and richness in Fort Solis that hasn't been seen before.

Did you end up using World Partition for the game’s development? If so, how effective a tool was it for your game?

Very early on in the development of Fort Solis, we decided we would utilize as much new technology as we could and not necessarily for the reasons people might think. As a very small team, resource management is key to every step of our development so using systems that could potentially be deprecated down the line didn't really make sense for us.

Instead, we wanted to focus on what was going to receive the most development time from Epic. This meant that we were able to get more support on these features and continually upgrade to newer versions of Unreal without too much trouble of holding on to legacy code.

World Partition became one such system that we adopted very early on. With a team of environment artists working towards some fairly aggressive deadlines, the ability for every one of them to simultaneously work in the same level was a complete game changer. Fort Solis is one large map so requesting ownership of it to add, change, or move an asset would have been excessively time consuming.
Courtesy of Fallen Leaf S.A
The character animation has been getting a lot of buzz. Can you talk a bit about how you brought the game’s characters to life using Control Rig?

Matthew Lake, Lead Technical Animator:
We opted to apply the Control Rig for its real-time applications to manipulate skeletons, or drive procedural animation; often coming in as a replacement for additive animations as it allowed runtime control and previewing for rapid iteration.

We used the Control Rig system extensively for driving deformation on the characters. Our skeletons inside of Maya were setup with constraints, bone limits, direct connections and various math operations to drive joints that will help improve the deformation of our characters and make them visually correct; so that means having additional joints to stop metal bending or stretching, or having the forearm twist as the hand rotates, or even rivets that pin the carabiners to the harness.

Normally, these joints would be baked directly into the animation and just played back in engine. Instead, we opted to mimic the character's rig setup within the Control Rig via a Post Process ABP which results in the skeleton being dynamically solved at runtime based on the current animation pose. This added a large degree of flexibility in our pipeline, as not only did it mean our animation files were considerably cheaper and more optimized requiring only the fundamental skeleton, but it also meant alterations, additions, or complete overhauls of our character rigs could happen without needing to re-export every single animation to contain the new rig data.

Control Rig was also used in many other areas in the ABP to procedurally create animation, such as within the examine object system. Based on player input via the joystick or gyroscope on PS5, we fed telemetry through a Control Rig graph to have the object be rotated in the player’s hand rather than be driven by authored animations.

The toolkit was also great for procedurally modifying the current animation pose through the Full Body Inverse Kinematics (FBIK) system, and we used it extensively for correcting the body poses on slopes or aligning them appropriately with the floor.
We understand that you’re hoping to deliver a “next-generation, visual, narrative game” with Fort Solis. What does that mean to you and how do you hope to achieve that?

We hope that players experiencing Fort Solis feel the level of immersion you would in your favorite TV show but this time you’re pushing the pace. We have hoped to remove gamey distractions, create fully realized visuals, immersive location, and compelling characters so that once you finally put the pad down you really felt your time investment was rewarded.

We can’t wait for players to play our unique cinematic experience.

Thanks for taking the time to chat with us. Where can people find out more about Fort Solis and Fallen Leaf?

You can Fallen Leaf on X and Instagram, and publisher Dear Villagers on X and Instagram. I’m on X as well.

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