The Vaulting Dead: Implementing first-person parkour in Dying Light

The debate over whether zombies should run or walk is an argument for the ages. What’s scarier: the unstoppable flood of drifting corpses à la Dawn of the Dead, or the sprightly infected seen sprinting in 28 Days Later?

What can be agreed upon is that once the recently risen learn to climb, humanity is doomed. It’s a nightmare scenario that Techland decided to explore in 2015’s Dying Light, allowing the dead to clamber up buildings and over fences. Fortunately, player character Kyle Crane is similarly gifted, making the most of his ability to climb, leap, slide, zipline and grapple across the open city of Harran to stay out of harm’s way.

“When we sat down to envision what Dying Light was going to be, freedom of movement was on top of the list and stayed there throughout,” recalls lead designer Maciej Binkowski. “Therefore, things like level design, object placement, mission design and even combat were all being built around the movement system.

“It came from our hope to take first-person perspective movement in open-world games beyond what was already out there. We know there were first-person games with big open worlds before Dying Light, but many parts of these worlds were off-limits – interiors, rooftops and so on. It often led to feelings of frustration; for example, when your epic hero couldn’t even jump over a knee-high fence and ends up being cornered. Yet a person in real life could have easily just jumped that fence.

“We also wanted a system that encouraged a ‘survival’ playstyle. In a real zombie apocalypse, what would most people do? They’d choose their fights wisely. They’d run away if need be. They’d try to get to higher ground. So freedom of movement let us design the game with that choice built in. It was ‘fight or flight’ – and not just one or the other on repeat.”

"Natural movement could become an industry standard."

Maciej Binkowski

Before Dying Light, Techland previously created fellow zombie title Dead Island for PS3, Xbox 360 and PC in 2011. While the titles share some similarities – the multitudes of brain-munchers the most evident – Dying Light’s transition to the new generation of console hardware and major gameplay alterations, including the presence of parkour, meant that the studio was essentially building from the ground up. 

“When we started out, we were basically manually putting in invisible interactive points where the player could grab and pull themselves up,” lead programmer Bartosz Kulon says.

“We called these ‘hooks’ and they were dotted across all our in-game assets. But to give the illusion of ‘go anywhere, climb anything’ we had to put a ton of these onto every wall, crate, street lamp, fence and so on. Pretty soon we had something like 50,000 hooks on one segment of the map and any movement or change in the level design would bring this all tumbling down. Even in testing it felt like we were constantly playing catch up; players were going to places we hadn’t predicted, so after each round of playtesting we’d have more and more hooks to place on top of the existing ones.

 “This was actually a major hurdle that could have derailed the whole project. Then, based on an idea that was proposed, our senior game programmer sat down on his own and prototyped a system that analyses the environment in front of you in real-time and, based on certain geometric conditions, decides if you can climb the object. If the conditions are met, then the climb animation is triggered. This was probably the biggest turning point for our entire development.”

Dubbed the ‘Natural Movement’ system, Techland’s dynamic approach to judging whether players could traverse a variety of obstacles provided a manageable method to allow movement across the studio’s biggest game world yet, which measures three to four times the size of Dead Island. 

“We could now ditch all those pesky hooks and just focus on ensuring the assets met the set conditions when and where we wanted them to,” Kulon continues. “Getting the first-person Natural Movement system to where it is now was still a lot of hard work, but the core idea from that early prototype was the seed that saved the game.”

Allowing buildings to be scaled was just the first foothold in Natural Movement’s integration. Techland then had to make sure that hero Kyle Crane was able to freely move around the environment, without breaking the reality of the experience – he may be a secret agent, but he’s not Stretch Armstrong.

“It was a mainly a combination of clever level design and keeping the experience realistic,” Binkowski says of the solution. “Our Natural Movement system was meant to remove all those pesky artificial barriers we’d come to expect in first-person games, but that didn’t mean our character could all of a sudden know no limitations. We just had to make sure that all obstacles in the game made sense: where we placed them and why they were there in the first place.”

This was particularly critical when it came to considering where Crane should and shouldn’t be able to reach, even with his newfound powers of parkour. The same logic had to be applied to pursuing zombies, too, with variant forms of the undead exhibiting different levels of agility.

“It all took lots of testing because suddenly we could go to spots we never intended,” Binkowski recalls. “We really had to change how we thought about level and environment design. Other major design changes were things like teaching our AI to properly climb and chase after you to ensure some challenge still existed when you were making your escape. Our loot and quests distribution also now had to incorporate this increased verticality and thus foster varied level design. We needed to place things of value and interest in hard-to-get places because we saw players would attempt to get there anyway when left to their own devices.”

To ensure that locomotion was kept on a human scale, Techland collaborated with professional free-runners. 

“Our Natural Movement system was coded entirely in-house so it was just lines and lines of code which we would test in our own game engine,” explains Kulon. “Methods to get the look and feel of the system included things such as working and consulting with various traceurs – parkour athletes – and looking at a ton of references in movies and games to find move sets that added the right feeling and experience. We also did a lot of experiments with GoPros attached to parkour athletes to see what first-person should or could look like. And then, of course, just lots of trial and error. Lots.”

This realism also meant Techland had to tone down some less believable elements offered by the world of games. 

“We reached out to David Belle and hired him on as consultant,” Binkowski recollects. “David is considered the creator of parkour, and he helped us refine the look and feel of how our character was responding and using the environment. With David’s help we were able to keep it about practical movement. In a game where you are in a zombie apocalypse, you’re not trying to impress people with things like triple backflips.”

"Getting first-person parkour to work saved Dying Light."

Bartosz Kulon

Think of a game with free-running movement mechanics. It’s likely to be a third-person action platformer, in the vein of Prince of Persia, Assassin’s Creed or Infamous, rather than a first-person shooter. In adopting a first-person perspective, Techland found itself faced with a number of user experience challenges.

“Motion sickness was one of the main ones,” reveals Kulon. “We did a lot of testing and tweaks to get that unfortunate response down to a minimum. It’s been improved immensely compared with what we were seeing in our initial tests. It was a mixed bag of tricks all coming together: the positioning and size of the HUD retackle, motion blur, and the speed and type of parkour animations.”

It wasn’t just the visual expression of parkour that changed in first-person. Players’ understanding of how to initiate the movement also changed.

“First-person meant the response time was something we had to tweak back and forth,” Kulon continues. “During initial tests, we saw that players were using the parkour button a little too soon. When you play Dying Light, you’re often looking ahead or up at the point you are aiming for. At that last crucial moment when you reach the very edge of the building you are on, you don’t see that edge on your screen. If you hit jump too early you often end up not making it to the other side. So we adjusted the response of the button to be slightly delayed. It’s not noticeable to the naked eye but it’s there, and it’s a sweet spot that we got to by adjusting it back and forth in microseconds.”

Binkowski adds that, once again, maintaining a sense of realism was key.

“We had a bit of tough time getting movement to look genuine in
first-person,” he details. “In third-person you see the whole character and can animate each part of the character’s movement accordingly; people see the whole picture and therefore feel the movement or response on some level. In Dying Light, we just have the main character’s two arms, and sometimes his feet, as the main visual on screen. So we had to get these limb animations, movements, portions and so on perfected, because before that often you’d just feel like your character was a floating camera.

“All of this and many other issues meant we often thought about going to third-person. But this was probably just out of frustration. Third-person has its own set of hurdles, so we just buckled down and pushed through.”

Free-running in games is nothing new – Prince of Persia: The Sands of Time arguably popularised the mechanic all the way back in 2003, with Mirror’s Edge taking it to a first-person perspective four years later.

Yet recent years have seen a wider variety of genres integrate freeform traversal into a number of different game types, from the open-world combat of Sunset Overdrive to mech-shooter Titanfall.

2016 looks to be another strong year for parkour’s popularity, with the return of Mirror’s Edge and Dying Light expansion The Following – although the next Assassin’s Creed has vaulted into 2017.

“It’s a couple of factors coming together,” Binkowski suggests as to the concept’s continuing prevalence. “In our case, it was all about creating that next step in movement. It was also a matter of authenticity.

“Free-running is trendy because it looks and feels spectacular, so it’s perfect for games. In a couple of years we will look back at today’s trends and see it as a natural evolution of gameplay. With better hardware comes new possibilities and gameplay mechanics, some of them turning into industry standards. And more realistic or natural movement has the potential to become one of them.”