Introduction

Owlcat Games is an independent video game development studio widely known for role-playing games like Pathfinder: Kingmaker and Pathfinder: Wrath of the Righteous. Since its founding in 2016, the studio has developed its own aesthetic principles and audio mechanics, which are in use to this day and constantly being improved with each new project.

In this article, I will discuss the approach to sound design and music that we took in our latest game: Warhammer 40,000: Rogue Trader (which I will simply call Rogue Trader from here on in) — not all of our techniques, but definitely the most interesting ones.

What is Rogue Trader? In short, it is the first full-fledged role-playing game in the universe of Warhammer 40,000. In it, you take on the role of a quite influential figure, a Rogue Trader, travelling through the perilous Koronus Expanse in a huge voidship in search of riches and accompanied by a party of companions. The game has the following core features: 1) a pseudo-isometric perspective, 2) turn-based combat, 3) a player-controlled party of heroes, and 4) multiple story branches and epilogues. If you enjoy playing classic Fallout, Dragon Age, or Baldur’s Gate (any instalment), you’ll probably like Rogue Trader too.

I was the audio director on this project, and my primary responsibilities were to form a new audio team and facilitate its work in any way possible. The core members of the team are:

Ilya Efanov: lead sound designer
Konstantin Kuzenkov: senior sound designer
Denis Filippov: sound designer
Artem Boksha: additional sound designer
Pawel Perepelica: music composer

Table of Contents

The Sound Design of Rogue Trader
      Artistic approach
      Location ambience
      Background voices in Low Gothic
      Character taunts and reactions
The Music of Rogue Trader
      Artistic approach
      Music mechanics
      Synchronization of sound with cutscenes and cinematics
      SoundFX component
      Mix tweaks for Veil degradation effects
Conclusions

The Sound Design of Rogue Trader

Artistic approach

In the universe of Warhammer 40,000, Humanity has entered a dark age. Most of its technologies have been lost, and the gods of Chaos, along with the many perfidious Xenos races, pose a constant threat to its existence.

The dystopian world of the Imperium of Mankind is portrayed as a bizarre blend of heavy metal fantasy and sci-fi elements, richly flavored with overtly religious themes. This is the atmosphere we tried to bring to the sound design of Rogue Trader as well. While we established an overall tone for the game as a whole (using keywords such as "gothic", "rusted", "dark", "epic", "gigantic", "religious"), we also created specific approaches for the many different factions: the Imperium sounds mostly "epic, decaying, and gothic", the Necrons evoke the feeling of "ancient but well-maintained technology", and the Dark Eldar sound mostly "organic and unnatural', while their spaceships and weapons maintain a distinct sci-fi character.

There are many different locations in the game, from barren dead worlds to overcrowded underhives. Each location gives off different sounds, evoking equally varying emotions: wind gusts and a light tonal drone to express emptiness, distant shouts and commands in Low Gothic for inhabited locales, monotonous hums and unsettling mechanical noises seeping from the cracks of Necron tombs. We really wanted to emphasize such details in each location to make them sound engaging even without music.

The combat in Rogue Trader is turn-based, which allowed us to concentrate on crafting truly over-the-top weapon sound effects. Each shot should feel like a reward, especially when tearing the enemy apart. We wanted players to clearly hear each hit or miss and the way projectiles echo off the walls. To make things livelier, we designed a complex banter system for companions as well as enemies. Not only do they react to standard combat events, but they also make personalized comments depending on who is in your party.

We wanted the player to "feel" those ancient mechanisms present in Rogue Trader as deeply as possible through their sounds; thus, we paid special attention to the game interface: weighty mechanical movements, electrical sparks, heavy metal impacts, and transitions that have an "analog" feel.

 

Location ambience

Ambience is critically important in our games. We strongly believe that it is a part of the narrative and should tell a story about the game’s location and setting. We strive to enrich these with various sounds that belong not only to the visible objects present but also to everything that happens around them. The main principle is that players should hear more than they can see.

To achieve this goal, we used the following approaches to the ambience mechanics and structure:

1. Room tones: Several (three or more) sound layers are played in equal balance across the stereo field. These layers typically include the main sounds in the setting that are not affected by the player's positioning — various gusts of wind, light breezes, insects, etc.
   
   The primary rule here is to keep the middle part of the audio spectrum free for other, more accentuated sounds. Even if a location has some wind or drone happening in the background, we usually cut at least 6db from between 250hz and 800hz to make some space.
   
   Another helpful rule is to have some movement in these layers. Nobody wants to listen to constant noise, so it’s good to occasionally change the pitch slightly or modulate a filter.
   
   
2. Specs or accents: These are one-shot sounds that randomly spawn in virtual space around the listener. They play a significant part in the ambience, introducing us to the general activities happening in a given area. Croaking ravens? Ringing bells? Distant worker banter and shouts? All these details let us know the main characteristics of the place we are currently in. Specs may be placed in the virtual space, their position randomized, or just be played in stereo or quad without changing their position. And, of course, we usually liven them up with delays, filters, and reverberation.
   
   
3. Sound emitters: These are simple — almost everything you can see in a location emits a sound, such as mechanisms, birds, running water, steam, gears, torches, etc.
   
   
4. Invisible sound emitters: Sometimes, you want a specific sound to play in a given place, even if that place contains no visible objects. For example, we added invisible cicadas and birds to various locations in Pathfinder: Kingmaker to make certain parts of it livelier or to catch the player’s attention.

So, the final soundscape for a location can be pretty complex. And sometimes, we add even more to it. Imagine you’re visiting an inhabited place — a town or a city. You would expect to hear people talking and gossiping all around, wouldn’t you?

Background voices in Low Gothic

In the grimdark future of WH40K, most people speak Low Gothic. As expected, you can't just look online and buy a library recorded in this language. So, we had to create our own. Fortunately, we already had some experience with this from making Pathfinder: Kingmaker, for which we recorded dozens of conversations and exclamations in gibberish to spice up the capital of the Stolen Lands. Thanks to this, the whole process was already familiar to us.

We decided that instead of recording a loop group for a large crowd, we would record single phrases in Latin that could be heard from different location points — usually in the distance rather than nearby. This way, we could use whatever crowd recording we had on hand and add some WH40K vibes to it. This was the most balanced solution for us budget-wise.

We also chose a few key reactions and wrote a selection of lines for each of them. These were:

• Agreement/Disagreement
• Anger
• Quarrelling
• Outcry (negative, positive, neutral)
• Crying
• Disappointment
• Drunken chatter
• Coughing

Of course, we tried to keep the text as nonspecific as possible since we would be using these phrases throughout the whole game.

After that, we hired 10 voice actors (five male and five female) and asked each of them to read the whole set, recording five to six takes for each line. This gave us a lot of options that we could use either individually or mixed together with other voiced materials. If you pay close attention while playing the game, you can hear these phrases being spoken in each Imperial hub!

Character taunts and reactions

Character sounds are divided into three broad categories: 1) body movements, 2) visual effects, and 3) voice. While the first two are pretty standard (you attach a sound to a Unity asset or assign it to an animation), ensuring the correct functioning of voiced reactions required a custom solution that I’d like to discuss further.

One of the central world-building features of Rogue Trader is our Asks system. An Ask is a line that is spoken by a character and triggered by a specific situation or mechanic, such as initiating combat, taking damage, noticing that your enemy belongs to a particular faction, etc. Our goal here was to create short, believable exchanges between our hero, their companions, and enemies. These exchanges can be instrumental for characterization and world-building, from helping us learn more about our party members — for example, that Argenta, a Sister of Battle, despises imperial psykers and has zero tolerance for anyone tainted by heresy or Chaos — to giving us insight into the inhuman practices of a group of chaos cultists when they taunt us at the start of a combat encounter.

To implement all of this, we created a so-called "Ask Component", where we assigned specific voiced lines to specific reactions and then defined their characteristics. These included things like how many different lines we might hear for a given reaction, how often we hear them, which plot flags we need to check for a given line to play, whether a line can be interrupted by another or not, etc. We also used this same component for combat shouts and grunts because of its flexible functionality.

One of the best things about this component was that it allowed us to freely change the voice of any given creature. Rather than attaching voiced reactions directly to a creature’s animations, we instead assigned these calls to an Ask Component, which could then be selected from within the creature's master asset (we call them Unit Blueprints). So, for example, when we wanted our servitors to sound more varied, we could just create additional Ask Components, assign different voice banks to them while keeping the original structures and Wwise event names, and then combine these with the existing animations in a Unit Blueprint. 

The Music of Rogue Trader

Artistic approach

Rogue Traders are a unique presence in the Warhammer 40,000 universe. The Warrant of Trade allows them to traverse the galaxy unrestricted and pursue otherwise strictly prohibited activities such as trading with Xenos. Like the corsairs of times past, they have been granted near unlimited freedom, although with the expectation that they will use it for the benefit of the Imperium of Mankind.

We had several primary goals when creating the music of Rogue Trader: 

1. Ensure it fit the world of Warhammer 40,000
2. Highlight the freedom of Rogue Traders and their resemblance to corsairs
3. Allow some experimentation to avoid having a purely orchestral soundtrack, as was the case in older WH40K games
4. Following Owlcat tradition, create music with prominent, highly emotional melodies.

Most of the tracks' base palettes consist of synthesizers, a choir, and an orchestra. However, different factions may feature additional elements in their music or employ different genres.

For example, on Footfall, a place where several Rogue Traders are constantly vying for influence, we added acoustic guitar and folk instruments to offset the Imperial grandeur with more shanty-esque elements. For locations dominated by Chaos, we used a lot of electric guitars, metal percussion, and distorted sounds. When dealing with the Dark Eldar, you can expect combat to be undercut by strong industrial themes. And whenever you board a space hulk, you will be accompanied by noise-ridden tracks that perfectly intertwine with the ambience of the void to produce a genuinely unnerving sensation. For a game that is 80+ hours long, diversity was key.

 

Music mechanics

Techwise, the music of Rogue Trader consists of exploration, combat, and narrative themes (usually played during cutscenes or dialogues). Combat tracks vary based on encounter difficulty — we created two versions of each combat track to highlight the difference between average and challenging fights. We also allowed the tracks to evolve by using a series of random fragments to make combat less repetitive.

One of our main challenges was avoiding repetitiveness in the music. To achieve this, we combined several different methods for both exploration music and combat music:

Exploration music:

• Usually consists of three long music cues divided by a one-minute pause to give the player some space to enjoy the location sounds
• Two of these cues should have more ambient character, while the third usually features a memorable motif that we call "the voice of the location". Its purpose is to create an association with that particular place within the player’s mind

Combat music:

• Consists of five to six short musical cues (we call them "phrases") that are randomly played in a 4–6-minute loop
• Two slightly differing sets of phrases are used for either easy/normal or difficult combat encounters. If the difficulty changes during the encounter, the music changes as well

The combination of these Exploration and Combat music cues makes up what we call a Location music set, of which Rogue Trader has twelve: 

Worlds:

• Imperial World
• Dead World
• Frontier World
• Garden World
• Tomb World (Necrons)
• Dark Eldar World
• Chaos Infested World

Space Ships:

• Imperial Voidship
• Space Hulk
• Voidship Hub

Other:

• Footfall (a large asteroid controlled by several Rogue Trader dynasties)
• Outer Space

The rest of the music is distributed along so-called "emotional themes" (music that highlights a specific mood and is usually played in dialogues or cutscenes), system themes (including the Main Menu theme, character generation theme etc.), and, of course, the boss combat encounter tracks. There are 69 in-game tracks in Rogue Trader that together last more than 3 hours — our longest score to date!

Now, I’d like to highlight some more technical moments that I think players might find interesting.

Synchronization of sound with cutscenes and cinematics

The first time we added complex cutscenes to our games was in the second DLC for Pathfinder: Wrath of the Righteous. Up until then, we had kept our cutscenes pretty simple because we were unsure how to execute the close and medium camera shots — games with isometric camera views usually don't have very detailed characters and textures, and we obviously didn't want to highlight our drawbacks during cutscenes, especially next to the graphics of AAA titles.

Nevertheless, after several internal tests, we decided that complex cutscenes improved the overall experience and artistic effect of the game, even with its more simplistic visuals. The next challenge, then, was figuring out how to add fitting sounds to these cutscenes.

Rogue Trader uses the Unity timeline as its master track for all animated sequences, VFX, and sounds. Our main problem was finding a way to synchronize the audio and visuals correctly.

Usually, all the sound effects are baked into one large audio track, which is given higher priority than the visuals — it’s fine if a few graphics frames are skipped, but you never want to hear the audio get out of sync with what you see, since this totally breaks immersion.

We used this method only for the Interchapters though. Whenever you start a new chapter in the game, a short video plays, introducing you to the next stage of your adventure: an Interchapter. Since it plays as a standard video file, we baked all the sounds, music, and voice-over into one audio track, and then our programmers wrote code that would always keep the audio and video strictly synced.

We didn't use this mechanic for the in-game cutscenes, however, as they involve a number of different game objects and units that must, for various reasons, function independently. Instead, we opted to break the cutscene audio tracks into several different layers and segments and then add these to the timeline at specific times, with the following parameters:

• Ambience is mostly played as non-positioned loops for the entirety of a cutscene
• Action sequences are divided up according to characters and segments and played as separate sound effects on the various game objects at specific times
• Cinematic sound effects and additional sounds needed for visual effects are also played separately and can be spawned either on game objects or as non-positioned sounds
• Units usually play footsteps, armor foley, and bodyfalls without any additional help

Generally, we didn’t granulate the cutscene audio very much. The primary rule here was to separate every significant action event or sequence, so that even if a cutscene stuttered at some point, it wouldn’t affect the rest of the audio. This way, we could still spawn sound effects on the game objects and ensure they always started playing at the right time.

Another interesting challenge here was that we sometimes had to re-score certain sounds that we were already using for unit animations or VFX, with the result that these were either too quiet or too loud depending on camera distance or angle. When that happened, we attenuated or muted these using Wwise States to make sure they didn’t clash with those of the cutscene track. 

SoundFX component

Another interesting audio feature we used is a Unity component that lets us mix different sounds in-game, allowing the sound designer to build a sound effect from several different layers.

I should point out that this is not our invention. When working on our first game, Pathfinder: Kingmaker, we studied the postmortems of several other RPGs. While examining the Dragon Age series, we learned how they managed to squeeze so many thousands of magic sounds into their memory budget: their solution was to make a set of basic sounds that could be combined with different parameters on a game object and then have it shape the final result to whatever visual effect was needed.

We thought this was a neat idea, so we implemented our own component that did almost the same thing. In ours, you can spawn whatever sounds you need and then set pitch, gain, and delay for each one.

This component allowed us to have plenty of variety while reusing a lot of the same sounds. Although we didn't create all of our sounds for VFX by combining layers in this way, this technique saved us quite a bit of time and memory with SoundFX. By and large, the only unique sounds we had to make were for the effects that couldn’t be covered by recombination.

Mix tweaks for Veil degradation effects

In the universe of Warhammer 40,000, there is another dimension made of pure energy called the Warp (also known as the Immaterium, the Empyrean, or the Sea of Souls). It is fueled by the emotions and souls of all sentient beings in the Materium, our own universe, and is also the home of the forces of Chaos.

The barrier between real space and the Warp is called the "Veil," which can be breached in numerous ways. In Rogue Trader, this usually happens when the player uses Psyker abilities, which rely on reaching into the Warp. This can lead to Veil degradation, where the Warp starts "leaking" into real space, with dangerous consequences.

Veil degradation can occur at any time in the game, so we had to create a system that 1) modifies whatever sounds are already playing and 2) adds something specific over the top of them. The driving force of this system is an RTPC called WeatherIntensity, which informs players about the current Veil degradation level, of which there are three: Wounded, Bleeding, and Torn (ordered from the lowest to highest).

When the game starts, an event executes a switch container with non-positioned sounds for these states. This switch is controlled by the WeatherIntensity RTPC, and that same RTPC then makes the necessary changes on the game busses and Actor-Mixers, including adding delay or reverberation, cutting the higher frequencies, adjusting the volume of the location sounds, and voice-over. 

Conclusions

Tech-wise, Rogue Trader is a direct successor to our Pathfinder games: all of them were made in Unity, use Wwise for audio, have an isometric perspective, and feature complex combat systems with dozens of characters. 

Since we don’t yet have the resources to implement super realistic sound behaviors in our games (things like sound propagation or early reflections), we instead have poured most of our efforts into creating vibrant and believable atmospheres for the worlds in which our games take place, whether they be the high-fantasy Golarion of Pathfinder or the grim-dark universe of Warhammer 40,000.

Wwise made this possible even for our small audio team. The main tip I offer here is to choose your priorities carefully. Ours is to always tell a captivating story that will be remembered even many years later, and the role audio plays in this cannot be overestimated.

Thank you for reading all of this. If there are any fans of our games among you, I hope you will enjoy the next adventure we will bring you.