Technical Director of Kojima Productions — on the reason for choosing the Decima engine for Death Stranding
Kojima Productions CTO on Why Decima Engine Was Chosen for Death Stranding
Kojima Productions has been using the Decima engine for nearly a decade and, by all appearances, has no plans to abandon it. In an interview with Automaton, the studio's Chief Technology Officer, Akio Sakamoto, explained why this particular software was chosen for the series about courier deliveries, road construction, and characters with speaking names.
Decima is the brainchild of Guerrilla Games, best known for the Horizon series. It was used to create both the original Death Stranding and the sequel Death Stranding 2: On the Beach.
According to Sakamoto, during the technology selection phase, the team gained access to the engine and conducted an evaluation. The developers were impressed by the rendering analysis tools, which provide detailed data without the need for third-party programs, as well as the development environment designed for large, multidisciplinary teams.
Sakamoto emphasizes that there is no universal engine, but Decima gives the studio the ability to do things that are difficult to implement in alternatives. This is precisely why the team continues to develop it alongside Guerrilla.
As an example, Sakamoto cited the opening scene of the second part, which the creators made inspired by the landscape of the Borrego Badlands in California. The developers visited the location, gathered references, and aimed for maximum authenticity. For the terrain, they prepared three types of geometry with different levels of detail and switched between them depending on distance. As a result, the scene contains about 25 million polygons while maintaining a stable frame rate—largely thanks to Decima's capabilities.
Special attention was paid to lighting. The team compared virtual light with real-world measurements and concluded that standard global illumination and shading methods were insufficient. The developers then added their own occlusion map for medium and long distances, which significantly improved the image.
The sequel also expanded the number of complex moving objects. In the fireworks scene, dozens of effects are active on screen simultaneously.
Even in the first part, we created a system capable of generating a large number of particles for BTs, and then expanded and modified it so that it could also render fireworks. When we refined the system for this task, it also became easier for us to experiment with reflections.
Akio Sakamoto
Sakamoto notes that Decima is not only used by programmers. The engine supports the entire production process—from graphics to internal tools. When necessary, Kojima Productions modifies the code and adds features for its projects, then shares the developments with Guerrilla.
When we need functionality specific to our projects, we modify the engine ourselves—and in some cases create entirely new features. We share these updates with Guerrilla at the source code level.
When we first started working with Decima, we launched regular meetings with Guerrilla—and we continue to hold them to this day. I'm not sure if our developments deserved mention in the "Special Thanks" section of Horizon Forbidden West, but in these meetings, we show the changes made, added features, and internal testing results. I think some of these solutions became a reference and were implemented in their version of the engine as well.
Akio Sakamoto