Interview
March 27, 2025
Inside the development journey of Clair Obscur: Expedition 33
Based in France, Sandfall Interactive’s small team of talented developers is on the cusp of releasing one of the gaming industry’s most highly-anticipated titles—Clair Obscur: Expedition 33. Although their development journey has spanned the past five years, the team’s distinctive yet clear vision for innovating within the beloved genre of turn-based RPGs has kept them focused on delivering something unique—-something memorable.
To achieve their goals, they chose Unreal Engine for its rich feature set and practical tools that enabled their small team to punch above their weight. Recently, we caught up with Sandfall Interactive’s Co-Founder and Lead Programmer Tom Guillermin to learn more about the influences for the project as well as the role UE5 tools and features such as Blueprint, MetaHuman, MetaSounds, World Partition, Lumen, Nanite, and more played throughout development.
To achieve their goals, they chose Unreal Engine for its rich feature set and practical tools that enabled their small team to punch above their weight. Recently, we caught up with Sandfall Interactive’s Co-Founder and Lead Programmer Tom Guillermin to learn more about the influences for the project as well as the role UE5 tools and features such as Blueprint, MetaHuman, MetaSounds, World Partition, Lumen, Nanite, and more played throughout development.
Thanks for taking the time to connect! Clair Obscur: Expedition 33 looks stunning. Could you please provide an overview of the game’s story and core gameplay experience?
Tom Guillermin – Co-Founder of Sandfall Interactive, Lead Programmer: Thanks for inviting us to chat! Our story is set in a fantasy world inspired by the Belle Époque, France. Once a year, the Paintress wakes to paint a cursed number upon her monolith and everyone of that age instantly turns to smoke and fades away. She first appeared 67 years ago, and year by year, that number ticks down. At the start of the game, she wakes and paints “33.”
Players join Gustave and his fellow Expeditioners as they embark on a quest to break the Paintress’ cycle of death once and for all.
As far as gameplay is concerned, the game is a reactive turn-based RPG. Players will need to master their offensive skills and magical abilities in battles and dodge, parry, and counter enemy assaults in real time. It’s a highly immersive evolution of the genre that makes each encounter feel more dynamic and engaging for players.
The world of Clair Obscur: Expedition 33 is inspired by a specific period in French history: The Belle Époque. What is it about that era that made you interested in basing a story around it?
Guillermin: It’s a time-period that hasn’t been explored that often in video games, especially within the turn-based RPGs that we wanted to make. For France, it was an important point in history that represented a lot for our country’s growth and culture, so it’s something that we really wanted to bring to life for our players in a way they have never seen before.
Could you tell us a little about the game’s influences, whether other video games or from the worlds of film, literature, etc?
Guillermin: There are a lot of inspirations that influenced our world. For example, the art deco movement was a big inspiration for us in building the look of our world. Some of that influence can be seen in other games like Dishonored, or Bioshock even, but we feel Expedition 33 does something a little different with it as we blend the art deco movement with the fantasy genre.
Additionally, the Belle Époque era itself, with its stunning architecture and art, obviously helped bring the world to life even more and helped give the game a more unique and original feel unlike anything else out there.
I think a lot of fans can see gameplay similarities to JRPGs like Persona, Final Fantasy, or Lost Odyssey too. I think some of these games, alongside some action games like Sekiro, helped inspire our battle system by combining traditional turn-based combat with more reactive timing-based counters and parries.
On the story side, there is also a French novel called ‘La Horde du Contrevent’, which is a fantasy novel about a group of explorers traveling the world, which our game also took some inspiration from as we made a story about people venturing into the unknown on a dangerous adventure.
All these influences (and many more) helped shape our original vision for the game and develop something that feels completely unique for players.
Tom Guillermin – Co-Founder of Sandfall Interactive, Lead Programmer: Thanks for inviting us to chat! Our story is set in a fantasy world inspired by the Belle Époque, France. Once a year, the Paintress wakes to paint a cursed number upon her monolith and everyone of that age instantly turns to smoke and fades away. She first appeared 67 years ago, and year by year, that number ticks down. At the start of the game, she wakes and paints “33.”
Players join Gustave and his fellow Expeditioners as they embark on a quest to break the Paintress’ cycle of death once and for all.
As far as gameplay is concerned, the game is a reactive turn-based RPG. Players will need to master their offensive skills and magical abilities in battles and dodge, parry, and counter enemy assaults in real time. It’s a highly immersive evolution of the genre that makes each encounter feel more dynamic and engaging for players.
The world of Clair Obscur: Expedition 33 is inspired by a specific period in French history: The Belle Époque. What is it about that era that made you interested in basing a story around it?
Guillermin: It’s a time-period that hasn’t been explored that often in video games, especially within the turn-based RPGs that we wanted to make. For France, it was an important point in history that represented a lot for our country’s growth and culture, so it’s something that we really wanted to bring to life for our players in a way they have never seen before.
Could you tell us a little about the game’s influences, whether other video games or from the worlds of film, literature, etc?
Guillermin: There are a lot of inspirations that influenced our world. For example, the art deco movement was a big inspiration for us in building the look of our world. Some of that influence can be seen in other games like Dishonored, or Bioshock even, but we feel Expedition 33 does something a little different with it as we blend the art deco movement with the fantasy genre.
Additionally, the Belle Époque era itself, with its stunning architecture and art, obviously helped bring the world to life even more and helped give the game a more unique and original feel unlike anything else out there.
I think a lot of fans can see gameplay similarities to JRPGs like Persona, Final Fantasy, or Lost Odyssey too. I think some of these games, alongside some action games like Sekiro, helped inspire our battle system by combining traditional turn-based combat with more reactive timing-based counters and parries.
On the story side, there is also a French novel called ‘La Horde du Contrevent’, which is a fantasy novel about a group of explorers traveling the world, which our game also took some inspiration from as we made a story about people venturing into the unknown on a dangerous adventure.
All these influences (and many more) helped shape our original vision for the game and develop something that feels completely unique for players.
Clair Obscur: Expedition 33 © 2025 Sandfall Interactive.
What is ‘Clair Obscur’ and what’s its relevance to the game?
Guillermin: ‘Clair Obscur’ refers to the real-world artistic and cultural movement which rose to popularity in France in the seventeenth and eighteenth centuries and helped influence the game’s artistic direction and broadly refers to the overarching world of the game, too.
It is a title that will mean a lot to the game’s story and it’s something we look forward to fans discovering.
While it appears that the game largely leans towards being a mature dark fantasy, there also seems to be lighthearted moments of character interaction and environmental exploration. Was this a difficult balancing act to achieve throughout the experience?
Guillermin: We drew some of our inspiration when making the game from JRPGs that we grew up with, and this blend of a serious story juxtaposed with lighthearted character moments and locations is something we really liked in those games.
When a game has a dark, emotional story, it’s sometimes nice to break that up with a lighter moment to release the tension and give both the characters and players a chance to take a break before diving back in. Finding the right balance between the two can be a challenge, but we think we achieved that with some of our more fantastic characters like Monoco and Esquie.
As they’re both non-human and live on the Continent, they don’t have the same life experiences as our core human cast, so they can bring a lot of new perspectives and a quirky sense of humor to the story, and I think fans will really look forward to meeting these characters and learning more about them...and their quirks!
What was your experience like when evaluating which engine to use at the onset of the project, and how did you end up selecting Unreal Engine?
Guillermin: When it comes to choosing a game engine for a first project, an important part of that choice is a matter of affinity between the workflows the engine proposes to their users and the content they want to make.
The origin story of Sandfall Interactive is a good example of that: Guillaume (Broche, Expedition 33’s creative director) was basically tinkering with a few game engines in his bedroom, as he had a specific story in mind that he wanted to tell. He clicked with Unreal because tools like Sequencer, the animation systems, or even Cascade at the time, all empower you to create meaningful content quickly. You also have Blueprint visual scripting, which is deeply integrated in the engine, and allows non-programmers to add logic to their content easily, which makes Unreal very approachable.
The overall Unreal ecosystem also played an important part at that time, with so many plugins, assets, and even template projects being available, providing good starting points to try different things.
Quickly after, I started working on the project and the choice of Unreal held up very well. As the team consisted of only the two of us, we kept using Blueprint to implement the core logic of the game, allowing us to keep collaborating easily and work on the same features, even though Guillaume didn’t have a programming background.
Later, as François joined, we founded Sandfall Interactive, and the team started growing. Some other parts of the Unreal ecosystem then became important, like having access to the source code for both the engine and many of the tools Epic developed around it, like Unreal Game Sync for example, which our team uses daily today.
Guillermin: ‘Clair Obscur’ refers to the real-world artistic and cultural movement which rose to popularity in France in the seventeenth and eighteenth centuries and helped influence the game’s artistic direction and broadly refers to the overarching world of the game, too.
It is a title that will mean a lot to the game’s story and it’s something we look forward to fans discovering.
While it appears that the game largely leans towards being a mature dark fantasy, there also seems to be lighthearted moments of character interaction and environmental exploration. Was this a difficult balancing act to achieve throughout the experience?
Guillermin: We drew some of our inspiration when making the game from JRPGs that we grew up with, and this blend of a serious story juxtaposed with lighthearted character moments and locations is something we really liked in those games.
When a game has a dark, emotional story, it’s sometimes nice to break that up with a lighter moment to release the tension and give both the characters and players a chance to take a break before diving back in. Finding the right balance between the two can be a challenge, but we think we achieved that with some of our more fantastic characters like Monoco and Esquie.
As they’re both non-human and live on the Continent, they don’t have the same life experiences as our core human cast, so they can bring a lot of new perspectives and a quirky sense of humor to the story, and I think fans will really look forward to meeting these characters and learning more about them...and their quirks!
What was your experience like when evaluating which engine to use at the onset of the project, and how did you end up selecting Unreal Engine?
Guillermin: When it comes to choosing a game engine for a first project, an important part of that choice is a matter of affinity between the workflows the engine proposes to their users and the content they want to make.
The origin story of Sandfall Interactive is a good example of that: Guillaume (Broche, Expedition 33’s creative director) was basically tinkering with a few game engines in his bedroom, as he had a specific story in mind that he wanted to tell. He clicked with Unreal because tools like Sequencer, the animation systems, or even Cascade at the time, all empower you to create meaningful content quickly. You also have Blueprint visual scripting, which is deeply integrated in the engine, and allows non-programmers to add logic to their content easily, which makes Unreal very approachable.
The overall Unreal ecosystem also played an important part at that time, with so many plugins, assets, and even template projects being available, providing good starting points to try different things.
Quickly after, I started working on the project and the choice of Unreal held up very well. As the team consisted of only the two of us, we kept using Blueprint to implement the core logic of the game, allowing us to keep collaborating easily and work on the same features, even though Guillaume didn’t have a programming background.
Later, as François joined, we founded Sandfall Interactive, and the team started growing. Some other parts of the Unreal ecosystem then became important, like having access to the source code for both the engine and many of the tools Epic developed around it, like Unreal Game Sync for example, which our team uses daily today.
Clair Obscur: Expedition 33 © 2025 Sandfall Interactive.
Clair Obscur: Expedition 33’s unique twist on turn-based combat enhanced by real-time mechanics is at the heart of the experience. What challenges did you face when developing these combat mechanics and how did you know when the gameplay felt right?
Guillermin: Early in the project, Guillaume and I created some prototypes of the reactive turn-based battle system, combining real-time gameplay for offense, like quick-time-events when you cast a spell or a free-aim mechanic, and defense, with our dodge and parry system. Even on basic prototypes, we felt it was bringing something fresh to the turn-based genre. Finding the right balance for those real-time elements took a while, especially timings for the dodge and parry, but I think we’ve reached a sweet spot today (and managing to land a counterattack after a series of successful parries just feels so good!).
I remember the first time we play-tested those features with the team, very early on, in a demo we had specially created to showcase the battle system. People on the team were trying to beat a boss in turns, passing the controller after a failed attempt. At that moment, we felt things had really clicked together and that we had managed to create something unique that would define the game.
The formula we ultimately came up with allows players who are good at real-time to take more risks, and other players can still counterbalance with specific items and strategies.
Guillermin: Early in the project, Guillaume and I created some prototypes of the reactive turn-based battle system, combining real-time gameplay for offense, like quick-time-events when you cast a spell or a free-aim mechanic, and defense, with our dodge and parry system. Even on basic prototypes, we felt it was bringing something fresh to the turn-based genre. Finding the right balance for those real-time elements took a while, especially timings for the dodge and parry, but I think we’ve reached a sweet spot today (and managing to land a counterattack after a series of successful parries just feels so good!).
I remember the first time we play-tested those features with the team, very early on, in a demo we had specially created to showcase the battle system. People on the team were trying to beat a boss in turns, passing the controller after a failed attempt. At that moment, we felt things had really clicked together and that we had managed to create something unique that would define the game.
The formula we ultimately came up with allows players who are good at real-time to take more risks, and other players can still counterbalance with specific items and strategies.
Clair Obscur: Expedition 33 © 2025 Sandfall Interactive.
The combat features a cinematic camera that adds visual variety to enemy interactions. How did development and implementation of this come about?
Guillermin: We wanted to have a high level of polish when it came to animation, camera movements, and VFX during battle. Even when you are simply navigating through the menus, something is always happening on screen!
To make sure we had the most flexibility in authoring all those elements, we used Unreal’s Sequencer, treating all skills as small cinematics, in which we dynamically bind battle actors. This approach gives the team a great deal of flexibility to create epic shots.
As we’re working on a turn-based game, the battle locations are essentially controlled environments, but our system still allows level designers to do case-by-case adjustments, like to enemy positions. One difficulty we faced was integrating dynamic movements in our level sequences (eg: an enemy jumping toward a character of your team, from whatever position it was). For this kind of feature, we would usually expose some actor properties to Sequencer and control them with keyframes in dedicated tracks, allowing us to retain artistic control of how a gameplay property evolves.
Guillermin: We wanted to have a high level of polish when it came to animation, camera movements, and VFX during battle. Even when you are simply navigating through the menus, something is always happening on screen!
To make sure we had the most flexibility in authoring all those elements, we used Unreal’s Sequencer, treating all skills as small cinematics, in which we dynamically bind battle actors. This approach gives the team a great deal of flexibility to create epic shots.
As we’re working on a turn-based game, the battle locations are essentially controlled environments, but our system still allows level designers to do case-by-case adjustments, like to enemy positions. One difficulty we faced was integrating dynamic movements in our level sequences (eg: an enemy jumping toward a character of your team, from whatever position it was). For this kind of feature, we would usually expose some actor properties to Sequencer and control them with keyframes in dedicated tracks, allowing us to retain artistic control of how a gameplay property evolves.
Clair Obscur: Expedition 33 © 2025 Sandfall Interactive.
Considering the gameplay depth and level of quality shown leading up to launch, it’s often difficult for many to believe that this is the debut title from Sandfall Interactive. How big is the development team and how has Unreal Engine helped you achieve your goals for the game?
Guillermin: We’re a core team of less than 30 people, split across our office space in Montpellier (around 25 people) and a smaller space in Paris (five people).
It’s quite a small team if you consider the scope of the project, in terms of both gameplay features and amount of content. Our team is incredibly talented, even though this is the first production for many people here at Sandfall, and Unreal Engine has empowered us to deliver on a vision that would have been impossible to execute a few years back with a team our size.
I think we also got particularly lucky that our development timeline coincided with the release of Unreal Engine 5, which was an absolute game changer for us, with many groundbreaking new rendering features.
I also mentioned Blueprints earlier, and I think that, when it comes to gameplay development, those were key in this project, allowing us to be very agile and create many features and content as a small team, in which not everybody knows C++ programming.
Before the programming team grew to a total of four, I remained the sole programmer for a couple of years. During that time, our mindset was to use Blueprint visual scripting as much as possible, as it gives a lot of freedom to non-programmers to understand game logic, try and suggest changes on their own, or add polish to existing features.
For a small team like us, it was critical to make sure everybody was able to access most of the project and not be blocked behind a wall of code. Of course, it comes with its own challenges in terms of production and review processes, but overall, this contributed a great deal to the depth of gameplay we have today!
Clair Obscur: Expedition 33 is visually stunning and features a hauntingly beautiful world. Was the art style something that came together quickly or did it evolve over time?
Guillermin: Our art director, Nicholas Maxson-Francombe, spent a long time working with Guillaume to really align on the art style and let it evolve into how it looks today. Our story is set in a French fantasy world, so we were really excited to design something unique that would feel special for our game.
I remember Nicholas always said his design process is “draw stuff he thinks is cool”! He’d start with some key ideas with Guillaume and go from there. And I think that unique way of working and developing the art style alongside Guillaume led us to the style we have today.
Guillermin: We’re a core team of less than 30 people, split across our office space in Montpellier (around 25 people) and a smaller space in Paris (five people).
It’s quite a small team if you consider the scope of the project, in terms of both gameplay features and amount of content. Our team is incredibly talented, even though this is the first production for many people here at Sandfall, and Unreal Engine has empowered us to deliver on a vision that would have been impossible to execute a few years back with a team our size.
I think we also got particularly lucky that our development timeline coincided with the release of Unreal Engine 5, which was an absolute game changer for us, with many groundbreaking new rendering features.
I also mentioned Blueprints earlier, and I think that, when it comes to gameplay development, those were key in this project, allowing us to be very agile and create many features and content as a small team, in which not everybody knows C++ programming.
Before the programming team grew to a total of four, I remained the sole programmer for a couple of years. During that time, our mindset was to use Blueprint visual scripting as much as possible, as it gives a lot of freedom to non-programmers to understand game logic, try and suggest changes on their own, or add polish to existing features.
For a small team like us, it was critical to make sure everybody was able to access most of the project and not be blocked behind a wall of code. Of course, it comes with its own challenges in terms of production and review processes, but overall, this contributed a great deal to the depth of gameplay we have today!
Clair Obscur: Expedition 33 is visually stunning and features a hauntingly beautiful world. Was the art style something that came together quickly or did it evolve over time?
Guillermin: Our art director, Nicholas Maxson-Francombe, spent a long time working with Guillaume to really align on the art style and let it evolve into how it looks today. Our story is set in a French fantasy world, so we were really excited to design something unique that would feel special for our game.
I remember Nicholas always said his design process is “draw stuff he thinks is cool”! He’d start with some key ideas with Guillaume and go from there. And I think that unique way of working and developing the art style alongside Guillaume led us to the style we have today.
Clair Obscur: Expedition 33 © 2025 Sandfall Interactive.
The characters in Clair Obscur: Expedition 33 are intriguing. Are there any specific UE features or tools you utilized to make them so memorable and believable?
Guillermin: As soon as Unreal Engine 5 was released, we switched our whole character creation pipeline to MetaHuman. Our cinematics were recorded as motion capture performances, including facial motion capture that was processed by the new MetaHuman Animator. There are also many smaller things we do using the Animation Blueprint to make our characters feel more alive, like adding micro-movements in the eyes or having dynamic “look-at” when an ally is attacked in battle.
Our Lead Character Artist Alan and our VFX Artist Léo also created a system in our character master material to manage dirt, blood, sweat, and tear levels dynamically, allowing us to make key moments of the story even more memorable and powerful for the player. As the characters go on an expedition in unknown territory, we felt they had to get some dirt on their face and clothing at some point! We also use the blood part of that system in battle when a character is low on health, to signify the urgency of the moment.
The fact that players can explore the World Map has many people excited. Were there any particular technical or creative challenges you faced when developing this aspect of the experience?
Guillermin: The World Map really is a small open world on its own, and as such we had to use most of the tools provided by Unreal Engine for this type of level: World Partition, obviously, in which the tuning of grid size and loading range was an important step. Our technical artist Alexandre set up HLOD generation specifically for that level to ensure a long view distance while preserving memory, which is critical for lower-end hardware and consoles in such a level with a lot of content.
This level also allows the player to navigate with Esquie, who is our friendly mountable balloon creature (also, he loves rocks). This came with a new set of challenges regarding navigation, especially considering you can fly freely with Esquie in the World Map and land anywhere. For this, we used a secondary NavMesh that was specifically tuned to Esquie’s size, as well as a tool we developed to generate customizable collision shapes, to ensure smooth and consistent navigation and air-to-ground transitions.
Guillermin: As soon as Unreal Engine 5 was released, we switched our whole character creation pipeline to MetaHuman. Our cinematics were recorded as motion capture performances, including facial motion capture that was processed by the new MetaHuman Animator. There are also many smaller things we do using the Animation Blueprint to make our characters feel more alive, like adding micro-movements in the eyes or having dynamic “look-at” when an ally is attacked in battle.
Our Lead Character Artist Alan and our VFX Artist Léo also created a system in our character master material to manage dirt, blood, sweat, and tear levels dynamically, allowing us to make key moments of the story even more memorable and powerful for the player. As the characters go on an expedition in unknown territory, we felt they had to get some dirt on their face and clothing at some point! We also use the blood part of that system in battle when a character is low on health, to signify the urgency of the moment.
The fact that players can explore the World Map has many people excited. Were there any particular technical or creative challenges you faced when developing this aspect of the experience?
Guillermin: The World Map really is a small open world on its own, and as such we had to use most of the tools provided by Unreal Engine for this type of level: World Partition, obviously, in which the tuning of grid size and loading range was an important step. Our technical artist Alexandre set up HLOD generation specifically for that level to ensure a long view distance while preserving memory, which is critical for lower-end hardware and consoles in such a level with a lot of content.
This level also allows the player to navigate with Esquie, who is our friendly mountable balloon creature (also, he loves rocks). This came with a new set of challenges regarding navigation, especially considering you can fly freely with Esquie in the World Map and land anywhere. For this, we used a secondary NavMesh that was specifically tuned to Esquie’s size, as well as a tool we developed to generate customizable collision shapes, to ensure smooth and consistent navigation and air-to-ground transitions.
Clair Obscur: Expedition 33 © 2025 Sandfall Interactive.
Not to be overlooked is the game’s compelling audio landscape, which features a heartfelt soundtrack and high-impact sound design during combat. Did MetaSounds play a role in developing and delivering the game’s audio?
Guillermin: The sound of Expedition 33 was handled entirely with the Unreal Engine Audio pipeline. The audio team used all the tools at its disposal, fully embracing the new possibilities offered by the MetaSounds, the Submix architecture, the Audio Modulation...and they strongly advocated in favor of updating the engine as soon as a new audio feature was released!
One of the best examples is the Interactive Music System, which is a cornerstone of the audio experience in a game where music’s playing almost all the time. This system relies on a Blueprint-driven Music Manager built by our Gameplay Programmer Florian, which manages several music contexts, one for each type of gameplay (exploration, battle, cinematic, menu, dialog). Each context is like a tape deck which can play one music at a time. When another tape deck needs to take the lead, each track (the former and the new one) performs a corresponding transition in or out.
And this is where the MetaSounds comes in. Each track is a Metasound, built from a preset, and driven by the trigger received from the Music Manager. We created a limited number of presets, all built on the same architecture, so it was easy to apply fixes and updates on a large chunk of tracks. The core ones are the playlists, which allow a track to play segments in a linear or random way, to loop or not... all the basic structure elements we needed to create interactive music.
Each playlist contains two playing decks, so we can overlap their intro and tails to create a smooth transition from one to another. Those playlists are then chained like blocks in the preset to create a more complex structure, with an intro segment followed by three random parts for example.
The transition from one playlist to another can be automatic, happening at the end of each section, or controlled by a trigger which triggers a transition on the next pulse. The pulsation itself comes from markers embedded in the wave files, allowing us to create a custom pulsation grid on each track (which is particularly useful when, like Lorien, your composer changes rhythmic signature all the time in the same track!).
And thanks to the ability of Unreal to handle multichannel audio files, we can even do all of that with up to four different mixes for each music segment, allowing us to smoothly swap mixes in real time and in perfect sync.
Guillermin: The sound of Expedition 33 was handled entirely with the Unreal Engine Audio pipeline. The audio team used all the tools at its disposal, fully embracing the new possibilities offered by the MetaSounds, the Submix architecture, the Audio Modulation...and they strongly advocated in favor of updating the engine as soon as a new audio feature was released!
One of the best examples is the Interactive Music System, which is a cornerstone of the audio experience in a game where music’s playing almost all the time. This system relies on a Blueprint-driven Music Manager built by our Gameplay Programmer Florian, which manages several music contexts, one for each type of gameplay (exploration, battle, cinematic, menu, dialog). Each context is like a tape deck which can play one music at a time. When another tape deck needs to take the lead, each track (the former and the new one) performs a corresponding transition in or out.
And this is where the MetaSounds comes in. Each track is a Metasound, built from a preset, and driven by the trigger received from the Music Manager. We created a limited number of presets, all built on the same architecture, so it was easy to apply fixes and updates on a large chunk of tracks. The core ones are the playlists, which allow a track to play segments in a linear or random way, to loop or not... all the basic structure elements we needed to create interactive music.
Each playlist contains two playing decks, so we can overlap their intro and tails to create a smooth transition from one to another. Those playlists are then chained like blocks in the preset to create a more complex structure, with an intro segment followed by three random parts for example.
The transition from one playlist to another can be automatic, happening at the end of each section, or controlled by a trigger which triggers a transition on the next pulse. The pulsation itself comes from markers embedded in the wave files, allowing us to create a custom pulsation grid on each track (which is particularly useful when, like Lorien, your composer changes rhythmic signature all the time in the same track!).
And thanks to the ability of Unreal to handle multichannel audio files, we can even do all of that with up to four different mixes for each music segment, allowing us to smoothly swap mixes in real time and in perfect sync.
Clair Obscur: Expedition 33 © 2025 Sandfall Interactive.
Were there any particular features of Unreal Engine 5 that stood out to the team during development?
Guillermin: Almost all of them! The new rendering features, Lumen and Nanite, were the ones that had the biggest impact on how we create levels and assets—for the better.
Lumen in particular has been a game changer for us, allowing us to iterate and try new ideas easily. Lighting is of key importance in our game as we work on each landscape like a painting, with composition, shadows, and highlights all working together to guide the player’s eye. Being able to work with real-time global illumination has allowed us to be even more creative and efficient with lighting in our scenes.
We also fully embraced MetaHumans for our character pipeline, allowing us to have realistic human characters and, combined with motion capture, a lot of body and facial expressivity in cinematics.
There are also many other rendering features and optimizations in UE5, like Virtual Textures, Virtual Shadow Maps, and PSO Precaching that we extensively used and those also helped us greatly towards crossing the finish line.
Niagara also played an important part in defining the visual identity of our game. As an RPG with its very own type of magic—which we call Chroma—VFX are an important way to convey the uniqueness of our universe, especially during cinematics and during action in battles.
Our VFX Artist Léo was already using only Niagara even before we switched to UE5, when it was still an Experimental feature in UE4. Niagara has been perfect to create all types of effects, from the most intense spells to more subtle cinematic elements like tears, and we’re always on the lookout for new features to create new effects.
Did your team tap into any of the Unreal Engine online documentation, learning resources, or other components of the ecosystem throughout development?
Guillermin: While we do obviously spend a lot of time in the online documentations to learn more about systems and follow guides, I would say many people in the team also enjoy watching replays of Epic’s streams or recordings of Unreal Fest talks, in particular when it comes to tech art, optimization, and best practices in general. We feel like those usually address the hot topics of the moment, which often are relevant to us as well.
The Unreal Developer Network (UDN) has been very valuable to us as well. As a small studio with a small programming team now consisting of only four programmers, knowing that we could get direct help from Epic staff on specific engine topics or issues allowed us to move further in the development of the project with the confidence that there would be a safety net if needed.
Another important source of information we used was the source code available on GitHub. Being able to browse changes, or view the history of specific files, has been useful more than once to integrate fixes from yet-to-be-released versions of the engine into our codebase.
Guillermin: Almost all of them! The new rendering features, Lumen and Nanite, were the ones that had the biggest impact on how we create levels and assets—for the better.
Lumen in particular has been a game changer for us, allowing us to iterate and try new ideas easily. Lighting is of key importance in our game as we work on each landscape like a painting, with composition, shadows, and highlights all working together to guide the player’s eye. Being able to work with real-time global illumination has allowed us to be even more creative and efficient with lighting in our scenes.
We also fully embraced MetaHumans for our character pipeline, allowing us to have realistic human characters and, combined with motion capture, a lot of body and facial expressivity in cinematics.
There are also many other rendering features and optimizations in UE5, like Virtual Textures, Virtual Shadow Maps, and PSO Precaching that we extensively used and those also helped us greatly towards crossing the finish line.
Niagara also played an important part in defining the visual identity of our game. As an RPG with its very own type of magic—which we call Chroma—VFX are an important way to convey the uniqueness of our universe, especially during cinematics and during action in battles.
Our VFX Artist Léo was already using only Niagara even before we switched to UE5, when it was still an Experimental feature in UE4. Niagara has been perfect to create all types of effects, from the most intense spells to more subtle cinematic elements like tears, and we’re always on the lookout for new features to create new effects.
Did your team tap into any of the Unreal Engine online documentation, learning resources, or other components of the ecosystem throughout development?
Guillermin: While we do obviously spend a lot of time in the online documentations to learn more about systems and follow guides, I would say many people in the team also enjoy watching replays of Epic’s streams or recordings of Unreal Fest talks, in particular when it comes to tech art, optimization, and best practices in general. We feel like those usually address the hot topics of the moment, which often are relevant to us as well.
The Unreal Developer Network (UDN) has been very valuable to us as well. As a small studio with a small programming team now consisting of only four programmers, knowing that we could get direct help from Epic staff on specific engine topics or issues allowed us to move further in the development of the project with the confidence that there would be a safety net if needed.
Another important source of information we used was the source code available on GitHub. Being able to browse changes, or view the history of specific files, has been useful more than once to integrate fixes from yet-to-be-released versions of the engine into our codebase.
Clair Obscur: Expedition 33 © 2025 Sandfall Interactive.
Do you have any advice for new studios who are in the process of determining which engine to utilize on their debut project?
Guillermin: When it comes to choosing a game engine for a first project, think of the types of content you will be creating and study how the various engines let you create those.
If you are a small team, take your time to understand and make the most of the engine you chose and avoid uphill battles, forcing the engine to do things that are too far out of its paradigm. You can be innovative, but still, you have to work with the engine, not against it. We worked for more than five years on this project, and we did our best to follow the workflows Unreal proposes, and I’d say doing so has allowed us to punch above our weight.
One last thing to consider is the ecosystem of the engine: learning resources, sample projects, and documentation provided with it, as well as the communities and the marketplaces supporting it. All those will be very important parts in the success of your project.
Thanks for your time! Where can people go to learn more about Clair Obscur: Expedition 33?
Guillermin: You can follow along on our official social channels on X, TikTok, Instagram, or BlueSky, or you can sign up to our official newsletter at Expedition33.com.
Guillermin: When it comes to choosing a game engine for a first project, think of the types of content you will be creating and study how the various engines let you create those.
If you are a small team, take your time to understand and make the most of the engine you chose and avoid uphill battles, forcing the engine to do things that are too far out of its paradigm. You can be innovative, but still, you have to work with the engine, not against it. We worked for more than five years on this project, and we did our best to follow the workflows Unreal proposes, and I’d say doing so has allowed us to punch above our weight.
One last thing to consider is the ecosystem of the engine: learning resources, sample projects, and documentation provided with it, as well as the communities and the marketplaces supporting it. All those will be very important parts in the success of your project.
Thanks for your time! Where can people go to learn more about Clair Obscur: Expedition 33?
Guillermin: You can follow along on our official social channels on X, TikTok, Instagram, or BlueSky, or you can sign up to our official newsletter at Expedition33.com.
How to install Unreal Engine
Download the launcher
Before you can install and run Unreal Editor, you’ll need to download and install the Epic Games launcher.
Install Epic Games launcher
Once downloaded and installed, open the launcher and create or log in to your Epic Games account.
Get support, or restart your Epic Games launcher download in Step 1.
Install Unreal Engine
Once logged in, navigate to the Unreal Engine tab and click the Install button to download the most recent version.
Watch how to install