Capcom is rebuilding its RE Engine for the AI era

Capcom used its in-house tech conference on 2 October to set out the future of the RE Engine, the technology behind Resident Evil, Monster Hunter Wilds and Pragmata. The plan is called REX, and the Japanese publisher describes it as gradually turning its engine into a game engine “for the AI generation”. That phrase alone was enough to worry plenty of players, who have watched generated art and synthetic voices creep into other games. The talk itself was mostly about the tools developers use every day, how long they wait and how they test their work. It also made it clear that Capcom wants its teams working alongside AI, and that deserves a closer look.

At a glance

Why the RE Engine needs an overhaul

The story starts in 2014. According to a report on the conference by Japanese site Gamebiz, that is when Capcom began building the RE Engine, which made its debut with Resident Evil 7 in 2017. More than 27 Capcom games have shipped on it since, including Onimusha: Way of the Sword, which we reviewed at launch, and almost every developer at the company, over 2,000 people, works with it every day.

Programmer Satoshi Ishida, who gave the talk, listed three problems that have built up over eight years of use. Games have grown so large that checking even a small change now means a long wait before it shows up on screen. Teams have also become more varied, with staff abroad and developers used to other engines, so the tools need to be simpler and work in several languages. Finally, AI is moving so quickly that building it into everyday workflows has become, in his view, essential to staying efficient.

Rather than starting from scratch, Capcom is upgrading the RE Engine piece by piece. Each new component carries a name beginning with “RE:”, and together they make up the REX project. That way the studio keeps a decade of know-how, and games already in production don’t have to switch tools halfway through.

Five tools built to save time

Most of the new RE Engine components shown on 2 October are about making developers’ lives easier. RE:Dox converts every kind of game data, from animation to settings, into a common format the machine can process faster. RE:UI rebuilds the interface of Capcom’s internal tools, which tended to freeze once too many elements were on screen, and it only redraws the display when a value actually changes. RE:Log stores error logs on a central server and can translate them automatically for teams overseas.

Two more tools reach into how the game itself gets made. RE:Flows lets staff build a game mechanic visually, then converts it into standard code automatically. A designer will be able to try out an idea without waiting for a programmer to write it up. RE:Runtime handles characters and objects in batches rather than one at a time, and translates the code written by Capcom’s teams into an in-house language called RE:C++, which runs faster.

Writing for PC Gamer, Rick Lane notes that RE:Flows sounds close to “vibe coding”, the habit of programming by describing what you want, while admitting it is hard to judge without seeing it in action. The Gamebiz report gives no rollout date for any of these tools.

Getting the RE Engine ready to work with AI

This is where the phrase that caught everyone’s attention comes in. According to Gamebiz, Satoshi Ishida ties all of these changes to one wider goal: making the RE Engine a game engine “for the AI generation”. The whole system now follows the rules of the world’s most widely used programming language, so that both humans and AI can read it. In time, Capcom pictures an AI that understands this code, writes part of it and plays test builds itself to hunt for bugs.

IGN sums up the publisher’s ambition with a quote from the talk: “Our goal is a future where we create games together with AI.” Capcom has also released some of this technology as open source, including RE:Dox and RE:Log, and Gamebiz says one of the aims is to help train AI models.

Nothing changes for players in the short term. The tools described affect how teams build games, and the talk never mentions generated images, voices or characters. What AI will end up writing or testing in future Resident Evil games is still an open question, and Capcom has yet to answer it. AI is already reaching games through other routes, as with the AI upscaling now available on the standard PS5. At Capcom, the change will mostly happen behind the scenes, inside the RE Engine and the tools of more than 2,000 developers.