CUSTOM GAME ENGINES: A Small Study

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A couple of weeks ago I played (and finished) A Plague Tale, a game by Asobo Studio. I was really captivated by the game, not only by the beautiful graphics but also by the story and the locations in the game. I decided to investigate a bit about the game tech and I was surprised to see it was developed with a custom engine by a relatively small studio. I know there are some companies using custom engines but it’s very difficult to find a detailed market study with that kind of information curated and updated. So this article.

Nowadays lots of companies choose engines like Unreal or Unity for their games (or that’s what lot of people think) because developing a custom AAA-level engine requires lots of resources, so, I decided to list here some of the most popular custom engines with the team-sizes and notable titles released with those engines.

Most of the engines listed here have been developed along the years with multiple iterations and multiple videogames, those engines have gone through several versions or even complete (or semi-complete) rewrites from scratch, with a consequent engine name change. Also, important to note, most of those engines use numerous middleware for specific functionalities (Platform, Physics, Network, Vegetation, UI, Rendering, Audio…).

*NOTE: I tried to be as much accurate as possible with the information about the employees count (I checked the companies websites, Wikipedia or company LinkedIn) but take it with a grain of salt (some employees numbers could not be up to date).

The BIG Companies

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*From left to right: Assassin’s Creed Odyssey, Final Fantasy XV, Red Dead Redemption 2

Below list is for very big corporations, sometimes with complex corporate structures with several divisions (not only focused on videogames) and various studios/subsidiaries developing games. Some of them work with multiple engines, not only custom ones but also licensed ones.

Company Employees Studios Engine(s) Notable Games
Activision/Blizzard ~9200 ~9 custom engine(s) Call of Duty series, Overwatch, Starcraft II
Electronic Arts ~9300 ~36 Frostbite 3 Star Wars Battlefront II, Anthem, Battlefield 1/V, FIFA 20, Need for Speed series
Ubisoft ~16000 ~54 AnvilNext 2.0 Assassin’s Creed series
Disrupt engine Watch Dogs series
UbiArt Framework Rayman Legends, Child of Light, Valiant Hearts
Snowdrop Tom Clancy’s The Division 2, The Settlers
Capcom +2800 ~15 MT Framework Monster Hunter: World
RE Engine Resident Evil 7, Devil May Cry 5, RE2:Remake, RE3:Remake
Konami +10000 ~30 Fox Engine Pro Evolution Soccer series
Square Enix +4600 ~18 Luminous Studio Final Fantasy XV
Nintendo +6100 ~8 custom engine(s) Zelda: BOTW, Mario Odyssey
Rockstar +2000 ~9 RAGE engine GTA V, Red Dead Redemption 2
CD Projekt +1100 ~4 REDEngine 3 The Witcher 3
Epic +1000 ~11 Unreal Engine 4 Fortnite

Usually those companies invest in custom engines to have full control over the technology and also avoid the revenue cut imposed by the licensed engines. Despite that fact, there are some big companies that in the latest years have chosen Unreal Engine for their productions, the most notable cases are:

  • Capcom is using Unreal for the new Street Fighter IV/V titles.
  • Bandai Namco latest big hits are using Unreal: Jump Force, Dragon Ball Fighter Z, Dragon Ball Z: Kakarot, Tales of Arise.
  • Square Enix also moved to Unreal for several new titles: Dragon Quest XI, Kingdom Hearts III, Final Fantasy VII Remake

It’s interesting to see that those big three are Japanesse companies, I wonder if that’s maybe a market trend for Japan. Also to note, the chinesse holding Tencent owns 40% of Epic Games, I bet it has some influence in the Asian market.

Middle-size Studios

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*From left to right: Rise of the Tomb Raider, Uncharted 4, A Plague Tale

Here we have the medium-small companies that decided to create their custom tecnology for their titles.

The number of employees could be a nice reference to consider because a custom game engine is usually developed in-house (I mean, not outsourced) but note that some of those companies could have a big number of people due to in-house artist/audio teams, while other companies out-source those parts of the development.

It would be really nice to know how many engineers are working on the engine division for each company, I’m sure there would be some big surprises, probably by the low number of engineers working in the engine and tools!

Also interesting to know more info about the tooling included with those engines, it’s really difficult to have access to that kind of information. Engines tooling is usually a hidden-secret (beside some GDC presentations or some quick showcase videos).

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*From left to right: Horizon Zero Dawn, God of War, Death Stranding

Company Employees Engine Notable Games
Infinity Ward +500 IW 7.0 Call of Duty: Infinite Warfare
Bethesda ~400 Creation Engine Skyrim, Fallout 4, Fallout 76
Valve Corp. ~360 Source 2 Dota 2, Half-Life: Alyx
Crystal Dynamics ~350 Foundation Engine Rise/Shadow of the Tomb Raider
Naughty Dog +300 Naughty Dog Game Engine Uncharted series, Last of Us
Crytek ~290 CryEngine V The Climb, Hunt:Showdown
From Software +280 Dark Souls engine Bloodborne, Dark Souls III, Sekiro
Remedy +250 Northlight Engine Quantum Break, Control
Guerrilla Games +250 Decima Killzone Shadow Fall, Until Dawn, Horizon Zero Dawn
Platinum Games ~250 Platinum Engine NieR Automata, Bayonetta, Vanquish
Santa Monica Studio +200 custom engine God Of War series
id Software +200 idTech 6/7 Doom, Doom Eternal, Wolfenstein series
Sucker Punch +200 custom engine Infamous Second Son, Ghost of Tsushima?
Insomniac Games ~180 Insomniac Engine Rachet&Clank series, Marvel’s Spider-Man
Quantic Dreams ~180 custom engine Detroit: Become Human
Asobo Studio +140 custom engine A Plague Tale
Mercury Steam ~110 custom engine Spacelords, Castlevania:Lords of Shadow series
Frozenbyte ~100 Storm3D Trine series, Shadowgrounds
Daedalic Entertainment ~90 Visionaire Studio The Whispered World, Deponia series
Kojima Productions ~80 Decima Death Stranding
Media Molecule ~80 Bubblebath Engine Dreams
Deck13 ~70 Fledge Lords of the Fallen, The Surge, The Surge 2

Some observations from this list:

  • Kojima Productions use Decima engine, developed by Guerrilla Games, despite not having a custom in-house engine, it’s surprisingly their accomplishments considering such a small team.
  • Media Molecule latest game/engine (Dreams) seems to have been developed by only ~15 coders, amazing!
  • Companies targeting one single platform, usually have less restrictions and can push the limits of that platform. Unfortunately, that’s a luxury that most companies can not afford.
  • Asobo Studio, the company that originated this market study is not that small… but, like other companies, they seem to work in multiple titles in parallel.

Small-size Studios (Indie Studios)

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*From left to right: The Witness, No Man’s Sky, X-Morph Defense

Here we have some really small studios that also choose to develop a custom engine for their games. Note that most of those engines rely on other libraries/frameworks for certain parts of the game, the common choices we find are SDL (cross-platform graphics/input), OGRE (rendering engine), MonoGame (cross-platform game framework, also relyes on SDL, SharpDX, OpenTK, OpenAL-Soft…).

One question many people could ask is, what parts of the engine are actually coded by the developers? Well, it depends, but usually coders take care of the screen-manager, entities-manager and content-manager as well as the wrappers/interfaces to the external libraries.

Second question, what parts of the engine usually rely on external libraries/middleware? It also depends on the company resources but usually audio-system, physics, rendering, networking, ui-system, terrain-system, vegetation-system and some other pieces.

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*From left to right: Factorio, Thimbleweed Park, Owlboy

On the following list (and the next one below) I added the publishing date (only +2012) and the link to Steam for all the games… there are not many games with custom engine from small studios out there and I think they deserve to be recognized and supported.

Some observations from this list:

  • Hello Games is a very small studio considering the size of No Man’s Sky and that they use a custom engine. Really impressive!
  • Runic Games was dissolved in November 2017, the founders created Double Damage, now they are working on Echtra Games on Torchlight III.
  • In most of those studios the people in charge of creating the game engine it’s only 1-3 persons!
  • Lo-fi Games was a one-man team (Chris Hunt) for more than 6 years!
  • Some of the games in this list took +5 years of development!
  • Not many games… a couple of hits per year…

One-man custom engines

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*From left to right: Stardew Valley, ScourgeBringer, Eagle Island

Finally, the list of the heroes.

Games developed by 1-2 people with custom game engines, engines mostly coded by one person! Respect.

Creating an engine and a game from scratch to the point of publishing it is an extraordinary accomplishment, not many people in the world is ready for that. Almost all of them are 2D games, usually with very small budgets and developed along multiple years. Congratulations to the developers!

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*From left to right: Axiom Verge, Ghost 1.0, Remnants of Naezith

Some observations from this list:

  • Some of those teams are formed by 1-2 people but probably grew at some point and/or outsourced some parts of the development (art, audio…). Usually the publisher also helps with some resources (localization, marketing…).
  • Omar Cornut from Lizardcube is also the developer of Dear ImGui, a free and open-source immediate-mode gui library used by lots of AAA custom engines.
  • Some of the games in this list took +5 years of development!
  • Not many games… a couple of hits per year…

There are some other remarkable games using custom engines (usually XNA/MonoGame) that worth mentioning: Braid (2009), Super Meat Boy (2010), Terraria (2011), Dustforce (2012), Sword and Sorcery EP (2012), FEZ (2013), Dust: An Elysian Tail (2013), Rogue Legacy (2013).

Conclusions

I’ll start saying I’m biased, I’m really passionate about videogames-making technologies and I admire custom engines and game-making tools. I also contributed to custom engines ecosystem with my grain of salt: raylib and several game-making tools. I prefer a custom engine over a licensed one, I consider that the extra amount of effort put into the product usually translates into some specific great mechanic or some amazing in-game details.

Said that, I must admit that creating a custom engine is a big endeavour and not many people are ready for that. I recognize Unity (and Unreal to less extend) have really democratized videogames development, lots of small-medium size companies can use Unity today to develop games quicly and put them on the market, sometimes with very low budgets… But, still, lots of big companies prefer to rely on their own custom technologies.

From my gamedev-teacher perspective, I think students must learn how engines work internally with as much detail as possible. Relying only on engines like Unity/Unreal for education to allow students develop eye-candy project in short-time is not the way to go. At the end of the day, someone has to write the engine and the tools!

NOTE: Feedback and improvements are welcome! 🙂

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