The Callisto Protocol is about to be released to survival horror fans around the world, and there is likely no better time to hear more about the technology that made it possible.
Twinfinite sat down with Striking Distance Studios chief technology officer Mark James to talk about the engine, visual effects, development challenges on the various platforms, and the work that goes into creating the beautiful and terrifying results that we’ll see on our screens.
We learn why the developer decided to stick with Unreal Engine 4, and how they managed to achieve the advanced visual effects that deliver the terror.
Giuseppe: Are the locations of the mutations on the body random or predetermined?
Mark James: Yeah, when they happen, and what type of mutation that happens is random. There is an amplifier so when I attack something and I’ve taken off his arm, it might grow an arm back. If it still has all these extremities it might just double up in size and so depending on what the current state of the enemy is, it determines what type of mutation. Also, where the tentacles come out, depends on what type of enemy it is.
So, for instance, there’s this enemy we call the big mouth, the thing that is spitting at you, that mutates from the head. Our standard grunts – we call them – mutate from the chest, so each enemy will show the virus in a different way, and then they will mutate in a way dependent on the remaining body shape.
Giuseppe: Your game looks very “wet” and I’ve always believed wetness is an important part of certain types of creepy horror…
Mark James: Yes. It is. Being wet evokes a sensation of disgust, and disgust is perfect for horror.
Giuseppe: Did you create some bespoke effects for that, or you just used the tools available in the engine?
Mark James: We have some quite complex materials that we used to create that and we wrote our materials system so that we can actually get some of these cooler effects. Other than that, yes, we use the engine, including volumetric clouds and smoke… it’s very good at doing that.
Giuseppe: Are you using Unreal Engine 5?
Mark James: No. It’s not 5. Everybody thinks we’re using Unreal 5, but this is 4.7, the latest version of Unreal Engine 4. Unfortunately, 5 came a bit late in the development cycle, and we’ve made a lot of custom modifications to 4 in lighting, material systems, animations, and more to fit our game, and porting those things over to 5 would have been really difficult with our time scale.
I think there are great games that are being created with 5, but we made our investment in 4.
Giuseppe: This is something I’m hearing a lot. There are a lot of developers that have started their dev cycle earlier than when 5 became available, and porting all their custom work would be really costly.
Mark James: It’s the same thing with every project. You make a decision on how you’re going to utilize the existing technology, and when you get to production, you don’t want to change the engine. You want to keep the same engine throughout it. Unreal 5 came after we started our production, and we did not want to change.
Giuseppe: Incidentally, another developer recently told me that if you’re in production and you need to change your engine, you have a problem.
Mark James: Absolutely.
Giuseppe: Yours is a sci-fi setting, and we’re used to clean, almost sanitized environments in sci-fi settings. How do you turn something like that into creepy, disgusting places?
Mark James: Our environments are a combination of organic materials and technology. When you see organic, that represents the presence of the Biofage. Normally, the prison has a clean, industrial look, but wherever the Biofage exists, we added this organic layer. It’s very obvious where the Biofage is and where it isn’t because you see this extra organic layer. In particular, when you look at the Rushers, which are these spider-like creatures, you can see that they take their prey and stick them to the ceiling, using their bodies to create these tendrils.
There are other places where the Biofage looks very different, all dependent on how the virus has mutated there.
Giuseppe: Speaking about disgusting stuff, this game seems to have a lot of gore. Is this something you actually had to do a lot of research for?
Mark James: Yes. We had to research it. Everything in our game goes through the process down to the way objects look. It doesn’t stop at the gore. Gore is all about three parts: we talk about our gore system, which is about dismemberment. We talk about blood and the way it behaves and splashes. The third one is chunking, which is the way some objects split off.
We researched each of these as a different set of R&D, and we look at the way the real human body behaves. That means looking at medical research journals, police reports, and other documents that are freely available. We didn’t go further than that because there’s quite a lot of information out there already about the way the human body behaves.
We even looked at real mutations within the human body, so when we do our mutations, we want them to behave and look as they would happen to a real body, just very, very quickly, but the end result looks realistic.
Giuseppe: Have you actually done some work in making your gore system dynamic, or the dismemberment happens in predefined ways?
Mark James: The dismemberment happens at certain body seams. You can take arms off and other things. On the other hand, the chunking and the blood can happen anywhere on the body. That’s generalized, while dismemberment is along certain seams.
Giuseppe: The Callisto Protocol looks quite advanced in terms of graphics. Was it challenging to make it run on old-gen consoles?
Mark James: One of the biggest challenges in any game is cross-generation development. If you start at the higher end and generate your assets at high quality, it’s a lot easier to represent these assets with a lower functional rendering on the older consoles. A lot of people start their asset production on low-end and then try to move it to high-end consoles, and that will always look bad. So we built this game as a next-generation console game first, and then we built our assets so that it was scalable down to old-gen.
Giuseppe: PC development has done this for years, after all.