At Gamescom 2022, Striking Distance Studios Chief Technical Officer Mark James revealed that The Callisto Protocol will support ray tracing. While the game is made with Unreal Engine 4, the developers also added some minor UE5 elements (though not Lumen or Nanite) to their custom version of the engine. James explained to IGN:
It was important for us to achieve a physically consistent lighting and shadow model in the game. Contrast and occlusion make great horror. Using our corridor-based scale of around 20 meters, we found that around eight lights could be affecting a surface of the environment. Unfortunately, we found that UE4 was limited to four shadow-generating lights, so first we worked on modifying the engine so that we could support a higher number of lights at a lower cost per light.
We looked at the UE4 ray tracing solution at the time and found that for the number of shadows we wanted to create, we needed to create our own solution. So instead we created a Hybrid Ray Traced Shadows solution that applies ray traced shadow detail to areas of the screen that matter to the overall scene quality.
UE5 took a very different approach for lighting with Lumen that didn’t fit the internal corridor model we wanted for the game, but I’ve been very impressed with the quality of the UE5 demos so far.
As we worked to finish The Callisto Protocol on UE4 we looked at areas of UE5 that we felt would be useful for both development iteration and new console features. Epic even helped us move some of these features back into our custom-made version of the engine. There’s no big components that stand out but instead lots of smaller optimizations and workflow improvements that have helped in the final few months.
Mark James was also interviewed by TechRadar. In that chat, he confirmed that The Callisto Protocol supports ray traced reflections in addition to the aforementioned hybrid ray traced shadows.
Our characters are the most realistic characters you'll see in a game. So much so that when we first showed our game, everybody thought it was pre-rendered. We were like, 'No, this is how our character looks. This is how Josh Duhamel looks'.
We've got a full scan, even down to ray-traced reflections for the eyeballs. So if you look into the character's eyes in our game, you can see their reflected optics. It’s a really tiny detail, but it's those tiny details that actually are so important to our game.
The game is out on December 2nd for PC, PlayStation 4, PlayStation 5, Xbox One, and Xbox Series S|X.