We explore the tech behind the dangerous open world of Days Gone.

Recently I had the privilege of meeting John Garvin, Creative Director at Sony’s Bend Studio, to discuss their PS4-exclusive hit, Days Gone. Ever wondered how the world of Days Gone feels so alive and dynamic? Garvin explains and sheds light on the development process behind this open world game that’s been lighting up the sales charts.

(This interview is lightly edited for clarity and readability purposes.)

John Garvin

Paul Hunter: Thanks for sitting down with us, John, and congrats on the success of Days Gone. Let’s begin with the game’s setting: you’ve selected the Pacific Northwest. I find most post-apocalyptic games take place in grimy wastelands or urban settings where nature has reclaimed the land, but you chose the scenic wilderness and high desert of the northwest. How did you go about choosing this setting for Days Gone?

John Garvin: Well, it’s where we live [laughs]. Bend Studio is in the middle of Oregon. Many people don’t know that Oregon, most of Washington and northern California are all high desert. It’s the Pacific Northwest, but it’s not what you think of; it’s not all dense rain forest and a lot of rain. There are a lot of very interesting geographical features and biomes compacted into a very, very small and harsh environment that’s been carved out over millions of years of volcanic activity. So you have this really cool range of environments all within a short bike ride. Twenty minutes to the west of where I’m sitting now is dense rainforest with snow-capped mountains, and 20 minutes to the east is the badlands desert, which is a large flatlands with juniper and elk. Super interesting place for us because we live here, but also because I’ve never seen a video game based here before. I like the juxtaposition of the brutality in the world against this amazing backdrop. If the apocalypse does happen, the high desert’s going to benefit from it. It’s not going to be harmed by it because there’s less pollution and fewer people messing it up, so the world will go on. That’s something I hadn’t seen done in a video game before.

Days Gone screenshot

Paul: After playing Days Gone, what amazes me the most is how alive it feels every second. One minute I’m battling a camp of Rippers, the next second some Freakers are rushing in, then I run out and encounter a pack of wolves. All these crazy things happen one after another. Is there some kind of A.I. director that controls all this?

John: There actually is! The open-world team worked really hard to make the world feel dangerous and live up to our tagline, “This world comes for you.” It’s a dynamic world where all those systems you talk about interact with each other. So, you know, the wolves will come out and attack you, but you can also see them run out and attack Marauders in the area. Or a Rager bear might come in that’s being chased by a horde of Freakers. These encounters are being directed at a super high level based on your personal experience. For example, the game always knows the last time you’ve seen a Rager bear. If you see one, it gets dropped out of the queue for a while. Over time, this creates a very dynamic experience where something’s always happening. By the way, I was playing the game the other day, and I saw an event for the first time. I’ve been playing this game for two years now and I had never seen this event, so I thought, “Wow, this is very cool.” It continues to surprise me years later, so by the time you beat the game, you will not have seen everything that can possibly happen.

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Days Gone screenshot

Yeah, there’s a master A.I. that sets up every creature type, and a hierarchy of who they should run from, and the conditions under which they should run.

Paul: Well, that’s just it. Every time I play the game, I see new scenarios and surprising ones at that. One time I remember wolves ran past me, then some Freakers ran after them looking for tonight’s dinner. So I took out the wolves and Freakers, but then some crows came down to feed on the carcasses—it was cool! Is there a food chain hierarchy that determines what creatures will eat?

John: Yeah, there’s a master A.I. that sets up every creature type, and a hierarchy of who they should run from, and the conditions under which they should run. So some creatures will attack you depending on where your health bar is, others will leave you alone if you’re not wounded. The same is true for every creature type in the game, and they’re all hungry. One strategy when you’re fighting Swarmers is to kill a bunch of them and run around so they lose sight of you. They’ll all start feeding on the corpses that you just created. Our intent was to create a dynamic, living world where the creatures were acting in ways they really would. That means being hungry, chasing after weaker creatures and [having] strength in numbers.

Days Gone screenshot

Paul: Speaking of Swarmers, I noticed there’s a whole bunch of Freaker types like Newts, Bleachers and Screamers. What are the biological connections between them? Are these different sub-species of Freakers? Viral evolutions? How does one Freaker type relate to another?

John: That’s a great question. You’ve hit on something I hope more players discover when they’re playing the game. Really what we’re trying to do with Days Gone is create a new creature type, and make sure we’re doing something gamers haven’t seen before. The questions you’re asking are the same questions the survivors are asking. They give these creatures nicknames and understand they’re different biologically and how they behave, but they don’t understand why. That’s what Nero is doing in the open world—they’re investigating as well. You’ll find there’s something like fifteen Nero intel spots where they’ve dropped micro-recorders, usually in sites they’re researching or caves where hordes are living. You can listen in on their attempts to answer those very questions. But yeah, in the broader sense I think you can say that there are many sub-categories of Freakers and it’s all based on how the virus mutates individually. The virus is alive, and it’s mutating these creatures in unpredictable ways. There are new creatures you haven’t discovered yet.

Days Gone screenshot

Paul: Days Gone has me thinking back to TV shows, books and movies I’ve enjoyed, like Lost, The Walking Dead and 28 Days Later. Were these influences on the team?

John: Well, I can tell you what mine were. All those shows you mentioned I’m a huge fan of, and Kurt Sutter’s Sons of Anarchy. Any references to those would be subliminal; I don’t remember deliberating thinking that I was going to write something that riffed on a specific show. My favourite novels are all post-apocalyptic, and they tell a human story of survival. So one of my favourites is The Road by Cormac McCarthy, which is again a bleak landscape, but the heart and soul of the story is a dad trying to keep his son alive and giving him some kind of future. That’s what I like about these settings and these stories: finding a way to tell a meaningful story against a very, very bleak and brutal landscape.

Days Gone screenshot

A lot of people don’t realize that was not a video; it was him playing the game live at the show.

Paul: I was there at E3 2016 when Days Gone was announced and we saw the trailer of Deacon running from what looked like a hundred plus Freakers. I’m sitting there thinking, “How can this be possible?” It doesn’t look possible on a PS4. But sure enough, I encountered the same spot in the game, and my whole screen was filled with Freakers. It looks like a technical marvel. How did you accomplish this on hardware released in 2013? 

John: Yeah, totally, right? So the actual number is 500 Freakers—the horde you’re talking about—and there are 40 of these hordes in the world. The one you’re thinking of is the Old Sawmill from our 2016 demo and Jeff Ross, our game director, actually played it live. A lot of people don’t realize that was not a video; it was him playing the game live at the show. It was our first tech demo for Days Gone because you’re right, when we started pitching this idea of an open world PS4 exclusive, we really had to come with something technology-wise that players hadn’t seen before and hadn’t played before. So a third-person shooter where you’re going up against this massive amount of creatures was a technological challenge that we spent the first two years of the project rendering, and how to make it fun. It was important to make the game look awesome and have different ways to use the environment, like setting traps and upgrading weapons. That all went into deciding how the horde was going to look and play.

Paul: Well, you certainly achieved your goal. Battling the hordes are my favourite moments in Days Gone. Thanks a lot for your time, John, and congrats again on the success of Days Gone!

Days Gone screenshot

A special thanks to PlayStation Canada, Sony Interactive and Bend Studio’s Creative Director John Garvin for their time. Interested in checking out the game? Days Gone is out now on PlayStation 4.

See also: NPD April 2019: Days Gone and Mortal Kombat 11 Dominate, Switch Continues to Shine