Ubisoft Talks ACU Tech: Multi-core CPUs, Lighting System, Mouse Acceleration, Next-Gen Development

Earlier this week, we had the pleasure of interviewing James Therien, Pipeline Technical Director at Ubisoft, who has been working on ACU for almost 4 years. James shared with us some interesting information about this latest Assassin’s Creed game. At this point, we’d like to give a big shout-out to CD Media’s Christina Arapakou. Without Christie, most of our interviews wouldn’t be possible. And now, without further due, here is the interview.

DSOGaming: Before we begin, please introduce yourselves to our readers.

James Therien: James Therien, Pipeline Technical Director. I have been working on ACU since the beginning (almost 4 years now). I have been working on the AC brand since AC1.

DSOG: Assassin’s Creed: Unity will be powered by the AnvilNext engine. What are the key differences between this version and the one that was used in Assassin’s Creed IV: Black Flag?

JT: Making a next-gen game of that magnitude with such a level of detail involved a great deal of people and took a very long time. But it remained a virtually impossible task without the proper tools. Since we are making more and more realistic games, we had to create the right tools to meet this challenge properly.

When those tools were created, the team could do away with all the redundant work and focus on quality tasks, not only on the functional aspect of the game. It allowed us to automatize the repetitive tasks like building placement. One of the many example we have is « Paris Pâté », which allowed us to place a district very quickly before letting the artist focus on the details of the buildings by makings layouts and focusing their creative juices on shaping rich interior atmospheres.

 Built with next-generation hardware and online environment in mind, the new Anvil has three major pillars support which powers Assassins Creed Unity;

*THEATRE – New state-of-the-art tools that enables us to push the boundaries of cinematic performance and animation. It is those ingredients that enable us to bring us closer to true dramatic performances.

*ZEN – Zen is our new system for productivity and infrastructure. It’s a game-changing pipeline in how we deal with next-gen assets and the interaction between global production team.

*CITY LIGHTS – Games are catching up to CG-level of quality and thus, high definition graphics are no longer the differentiation factor. True differentiation comes from mastery of volumetric cinematography; the ability to master art direction in a 3D physical space. City Lights encompasses all the tools that enable us to create a realistic Paris that is more immersive on a cinematographic scale. 

DSOG: One of the biggest gripes we had with AC IV: Black Flag was the fact that it was mainly using one CPU core. Will Assassin’s Creed: Unity be better optimized on the PC than AC IV: Black Flag? Will it take advantage of more than four CPU cores?

JT: Globally, our engine scales very well to multiple cores. Unfortunately, we hit different bottlenecks on different platforms. Traditionally, on higher-end PCs, we would be graphic driver bound, negating the benefits of having more cores. On ACU we completely changed the renderer architecture to drastically reduce the number of draw-calls we make to the driver. You should see much more scalability on ACU.

DSOG: We know that Ubisoft has a strong relationship with Nvidia. Can we expect any specific PC features for the PC version of Assassin’s Creed: Unity?

JT: Yes. We have a strong and productive collaboration with NVIDIA. And players can expect some PC-specific features for Assassin’s Creed Unity. The exact list is going to be announced later.

DSOG: What are the key tech features of Assassin’s Creed: Unity, and what is the one feature that you are really proud of?

JT: There are so many features; it’s hard to choose one! I think what I am the most proud of is the quality of immersion. The combination of the rendering quality with the overall density of detail in the game makes you feel like you are in a real city more than ever before.

DSOG: The lighting system of Assassin’s Creed: Unity seems to be overhauled. Can you share more details about it? Do you support Global Illumination and if so, is it more advanced than the one used in AC IV: Black Flag?

JT: The renderer is total re-write.  We knew we wanted a much richer image with better contrast. We started with a physically-based renderer. We then looked at how we could make a dense urban environment look really good. We’ve always had nice image quality when in the sun or in partial shadow in previous ACs, but we were somewhat flat in shadow. We started by looking at how the sky, not just the sun contributes to the scene. We then added volumetric GI. The city streets really started to come alive. At that point we were getting more interesting results in-game than our initial off-line concept renders. Later when we decided to go with interiors, it just worked.

DSOG: Pop-in of distant objects has been an issue in most AC titles. Since this is a current-gen only game, have you found ways to eliminate it?

JT: We’ve greatly reduced it. The loading range is further; we’ve also been looking at different techniques to have a smoother transition.

DSOG: Assassin’s Creed: Unity is only coming to current-gen consoles and PC. What are the advantages of developing a game for only these platforms, without the need to compromise your vision for old-gen consoles?

JT: It’s quite liberating to design for a new generation. We also were fortunate enough to have enough time and a talented team to push the boundaries. We were able to think about all the elements that make up the game: rendering, lighting, animation, characters, etc. We also had time

DSOG: Assassin’s Creed IV: Black Flag was CPU limited for a lot of gamers. Have you considered taking advantage of AMD’s Mantle API and what’s your opinion about it? Are there any plans of implementing it to the AnvilNext engine or will you wait for DX12?

JT: As I said, we totally rewrote the low-level renderer for ACU. One of the reasons is to deal with the same types of issues that are solved with Mantle and DX12. We’re finding ways to push the hardware to its limits.  I can’t speak for future projects, but we’re always on the lookout for the best technology to improve our game experience.

DSOG: What kind of PC systems will players need to enjoy Assassin’s Creed Unity (60fps at 1080p)? Any estimated PC minimum requirements?

JT: Sorry, I don’t have the exact specs yet, we’re still in the last stretches of the optimization.

DSOG: Assassin’s Creed: Unity is coming only to current-gen platforms. Which brings the question: Will it be scalable so it can run on weaker PCs or will PC gamers need to upgrade their systems to enjoy it even on Low settings?

JT: You are right; a big challenge of the ACU PC team is scaling down, not up. Our game is truly next gen and will require more powerful PCs than in the past. We’re doing all we can to make sure the most people can enjoy the game.

DSOG: All previous Assassin’s Creed titles suffered from mouse smoothing/acceleration side effects on the PC. Will there be an option in ACU to toggle mouse smoothing?

JT: Yes, we are aware that some of the users did experience some mouse smoothing/acceleration issues. It’s one of the elements we are trying to address on ACU.

DSOG: Will there be any graphical differences between the current-gen console (PS4 and Xbox One) version and the PC version? Will you take advantage of the additional raw power of current-gen PC GPUs or are you targeting for parity across all platforms?

JT: We try to deliver the best experience we can. If you have the very latest GPU and a very beefy PC, you should be able to run ACU at higher resolution and with somewhat better settings. But whatever the platform, you will see a Paris and its inhabitants like you have never seen it before.

DSOG: How close to a high-end PC are current-gen consoles?

JT: At the very high-end, PCs have the edge: but you have to spend a lot more money to get there. I think for most people, the consoles are comparable to their PCs.

DSOG: What’s your opinion about PC gaming in general? Is it a profitable platform and do you consider it as important as the current-gen consoles?

JT: I can’t speak about the business side of things, but technically I think we have a short window where the consoles and the PC are close in terms of architecture and horsepower. This is great news. Because of this, the major re-work we did on the renderer was made for PC first. This is not something we could have done in the past.  This convergence is an opportunity for everyone to have access to better games! 🙂

DSOG: Thank you very much for the interview, any last words you want to share with our fans?

JT: The team worked really hard and for a long time on this project. I think it shows. I sincerely hope you enjoy ACU as much as me!

John Papadopoulos

John is the founder and Editor in Chief at DSOGaming. He is a PC gaming fan and highly supports the modding and indie communities.Before creating DSOGaming, John worked on numerous gaming websites. While he is a die-hard PC gamer, his gaming roots can be found on consoles. John loved - and still does - the 16-bit consoles, and considers SNES to be one of the best consoles. Still, the PC platform won him over consoles. That was mainly due to 3DFX and its iconic dedicated 3D accelerator graphics card, Voodoo 2. John has also written a higher degree thesis on the "The Evolution of PC graphics cards." Contact: Email