"We don't want to force one terabyte of data on the players": Assassin's Creed Shadows' tech director on the clever tricks Ubisoft uses to "go beyond" current-gen

I'm sitting down to talk with Pierre Fortin, the brand and pipeline technology director at Ubisoft Quebec, to discuss Assassin's Creed Shadows. Yet, it's hard to do simply that. Part of the Anvil team, the in-house engine that powers the series and has seen plenty of overhauls, Fortin works in the context of the games that came before – but also with a constant mind towards what comes next, predicting where the team will need to scale before trends actually materialize.

"My role is to basically advise other directors," Fortin tells me. "Early on in conception, we look at the future in front of us in terms of tech. We advise on what we think we should be doing, how we should be leveraging new technologies. Then, I work closely with the engine teams to make sure that that vision that we have – at the direction level – gets implemented into features and makes it into the hands of the players."

London to Japan

After starting out on the tail end of Assassin's Creed Unity, working to optimize the game before release, Fortin's first full project was Assassin's Creed Syndicate, which means he has plenty of experience on the series when it was focused around open world cities, right before the switch to an open world RPG structure incorporating much larger worlds. For players, the shift in direction from Assassin's Creed Origins onward was huge. But I can't imagine what it was like from a technical direction, to move from one set structure that Ubisoft had refined to the nth degree into uncharted territory.

"In fact, it is quite complex," confirms Fortin and we laugh – it's an understatement. "In a city like we had with Syndicate, Unity, our big Global Illumination pipeline at the time was made for that kind of dense city. If we extrapolated, for example, [those] kind of date requirements [...] to a world like we have with Shadows, Origins, Odyssey, the number would have been 1.9Tb of data or something like that." Naturally, the whole system had to be completely rethought with a new approach.

It's a great way to illustrate the true magnitude of how far Ubisoft has come even from the first PS4/Xbox One console exclusive title in the series with Assassin's Creed Unity to the first PS5/Xbox Series X one with Assassin's Creed Shadows. The tech team has been refining this new system radically each release, all the way through to the new game. "The seasons bring their own global illumination," Fortin confirms – there's layers on layers. "Evolving the engine to scale from something like six square kilometers to 256 or something like that is a huge task, and touches all aspects of the game production."

Hardware has improved a lot to match, so I can't help but ask if the team felt a lot of freedom with Assassin's Creed Shadows dropping last-gen consoles. Fortin laughs again. "When you start with a new generation, you always feel like you're unshackled, in a way, but then you're developing, and you introduce new systems, and you find new barriers at some point," he says.

"With [AC] Shadows, I think we've really tried to push the world's dynamism to a new level." He brings up trees as an example, pointing out that in previous games they'd use simple shaders ("a little program within the program that controls how vertices are displayed") to generate small amounts of movement. "But now, in AC Shadows, we leverage the new power of those new consoles and this new hardware to implement fully physics based animation for our trees, so they react and they move with the wind with a thread simulation." All while, he points out, still being playable on PCs with less up to date hardware, who might not have ray-tracing support.

Dynamic duo

Implementing advanced weather effects as well as lots of dynamic, on-screen movement, has been a long time coming, and something of a pipedream for both Fortin and art director Thierry Dansereau. Fortin says it's been brought up on past titles as the two have worked together a lot over the years, but just hasn't been feasible to pull off until this point.

"To us, both of us, we felt like movement on screen was something that we needed to have," says Fortin. "I like the fact that this came as a request from artistic direction to implement this, because at the technical level, I strongly felt at the time this was what new-gen was." In a lot of games from older generations, "the screen is static", Fortin says. Barring specific key elements, "it didn't feel alive." Having both departments across tech and art aligned in this vision was important for Assassin's Creed Shadows, Fortin tells me. "That's where the magic happens!" he says, "When we are both aligned, it's easy to mobilize both the artistic teams and the engine and rendering teams to make that happen."

As a result, the teams came up with lots of new systems that could work in concert to bring Japan's beautiful landscapes to life. "Our fluid based wind system is one of them, plants moving with the wind another also," Fortin continues. "Also all our new particle systems, when you're moving in the forest and you're seeing leaves, they're moving with their wind pattern. All of those were built with that in mind." When the disciplines are able to come together like this, it's possible to create some incredible strides forward in what's possible.

When Fortin talks about dynamism, though, he doesn't mean movement exclusively, "but changes in the world." The time of day changes gradually, snow falls and melts, and you move through every season periodically. "That's what we wanted to push, and that's something that the new power of the consoles really helped us to achieve," Fortin says.

Don't think the seasonal load screens are simply pulling different versions of the map in. It's all, as you might expect from Fortin's impressive tech team, much more dynamic than that. To test it for yourself all you need to do is put the controller down and see it in real-time, from puddles collecting and easing off gradually when it rains, to snow literally piling up.

"We implemented a system which we call the 'multi state entities'," explains Fortin, an 'entity' being essentially an object in the game world. "In the past, there was not a concept of having different states. If you built a chair, you had a chair. But now, with that system, what we have is a chair that, for example, can adapt to being placed in winter." This means the chair itself can know how to present itself based on what's going on in the world around it, generating a snow cover, for instance.

It's not that different to checking out the window to know you have to put on a raincoat, but something that's absurd to comprehend on such a massive scale. This system applies to loads of entities all at once. "The vegetation system also knows about the current season and is going to adapt, for example, the amount of leaves that we have in the trees. All of the particle effects that we're going to spawn are going to be based on rules based on the active season," says Fortin. Smart use of these systems has been vital to not just having the ability to show objects differently, but allow them to exist in the in-between states of the world changing around them.

Weathering the storm

Going back to feeling freed from limitations until new ones are found, Fortin says it's "the complexity of the world" that offered up the biggest challenge for Assassin's Creed Shadows. "If you think of it. We have four seasons. We have two protagonists. We have a world that's pretty big. We have dynamic time of day. And on top of that, you have weather," he says.

"You have kind of three axes. You have one axis which is time of day, and you have one axis which is weather, and then you have another axis which is [the] season." Combining them all together, accounting for how they overlap, presents a tremendous technical challenge, especially to ensure the game performs well in all sorts of situations. "That's been quite a challenge," Fortin says. "I'm pretty happy with what we've been able to achieve there. No matter the circumstances, we have a good experience that is on par with the performance target we had."

Size has been another, an ever-present threat even beyond the massive amounts of potential lighting data mentioned at the start of our chat. "Just putting all of that data into the disc is a challenge by itself. We don't want to force one terabyte of data on the players. We put a lot of effort into having, you know, clever compression techniques to make sure that we're okay, that we fit within our desired SSD space," he says.

There's no rest. But there's still plenty of excitement for Fortin and his colleagues around what's possible next, testing the thresholds, and then working to push past. "As soon as we have new hardware, we're pretty good at maximizing it, and reaching those new limits," he says. "But it's through clever optimization techniques that I think we go beyond them."

You can find out what's next in store for the game with the Assassin's Creed Shadows roadmap. Looking to play another game in the series? Check out our best Assassin's Creed games list!