"We really squeezed the PS5 as much as we could": Ubisoft talks tech on Assassin's Creed Black Flag Resynced

We recently had the chance to speak to two members of the development team behind the upcoming Assassin's Creed Black Flag Resynced: technical director Jussi Markkanen and Nicolas Lopez, technical architect. They went some way to justifying the project as a proper ground-up technical reimagining rather than a simple remaster - and one that maxes out the PlayStation 5 console.

"We really squeezed the PS5 as much as we could", says Lopez - so much so that they feel it will be "very difficult to extract more from these platforms" when it comes to charting out the next mainline Assassin's Creed release. "We'll have to work hard for the next game", he laughs, "unless there are new consoles!"

That challenge is down to the extent to which the development team were able to ramp up RT performance, ensuring that RTGI is used on all consoles and in all modes, while also pushing scene density higher than in Assassin's Creed Shadows - and ensuring a lock to each mode's frame-rate target too.

From what we've seen so far, the team's work has absolutely paid off - but let's rewind a bit and start from the basics when it comes to the project. As you may know, the new release is built on the improved Assassin's Creed Shadows version of Anvil, but virtually all of the game's original content has been remade to suit a fully modern PBR (physically-based rendering) pipeline. The original Black Flag assets simply were not authored with physically based shading, ray tracing or micro-polygon detail in mind, so tests by the development team showed that selective upgrades wouldn't have the desired effect. Instead, artists rebuilt meshes and materials from scratch, using the 2013 game as a guide rather than a constraint, targeting dense geometry and PBR-correct materials that still evoke the original art direction.

One of the defining shifts is in scene density and crowd complexity. The Havana cityscape - already a technical highlight in the original - has been reworked into an exceptionally dense environment that actually doubles AC Shadows in terms of asset density and crowd count. That change makes ensuring reasonable frame-rates a tough challenge for current-gen consoles - especially as Black Flag's world and missions were already set. With no real freedom to change layouts or simplify sightlines, all optimisation had to happen within the constraints of the existing level design and quest structure. As a result, the solution was to embark on a quest for systems-level scalability across CPU and GPU instead.

Gameplay systems have been modernised in parallel with the renderer. Stealth has been overhauled with "crouch anywhere" support and light/shadow stealth mechanics, moving away from the original's reliance on dedicated stalking zones that feel a bit archaic by 2026 standards. That required revisiting old level design setups and tuning them for a very different stealth model that reacts to illumination rather than fixed volumes. Destructible environments are another major shift: where Black Flag largely relied on static props, Resynced uses technology proven in AC Shadows to make small environmental elements physically destructible, with gameplay hooks such as kicking enemies through destructible clutter for staggers. In other words, the game's systemic layer has been updated to take advantage of the new simulation and rendering features, not just its visuals.

Character work has seen similar attention. The strand-based hair system from Assassin's Creed Shadows returns, but it is optimised better and deployed more widely, including across crowd characters. The team found that the system "didn't work so well" with blonde hair - more common in Black Flag's setting than in Japan - so specific shading and lighting adjustments were made to handle that material correctly. On the facial side, the brief was to preserve the original motion capture performances - which are regarded internally as iconic, while driving far more detailed face meshes with complex shaders, wrinkle maps and layered deformation. A simple retarget of the old mocap to the new rigs only got them "maybe to 60, 70 percent... and the end result was not great", according to Markkanen. The answer was building a multi-stage transfer pipeline, then relying heavily on manual artist work to restore nuance, particularly around the mouth and eyes, adding new micro-expressions - without violating the iconic original performances. The eyes were easy, according to Markkanen, but the mouth movements required a lot of extra attention.

Rendering-wise, one of the central challenges was reconciling the look of a pre-PBR, seventh-generation title with a physically-based, ray traced pipeline. Lopez talks explicitly about trying to be "faithful" to the original, while acknowledging this can only go so far. Many of the maps and tricks used in the 2013 release simply do not map directly to a modern BRDF-based system, and volumetrics and shadowing have evolved significantly since then. The solution was to chase the intent and memory of the original rather than the literal implementation: the remake is designed to look like you remember Black Flag looking, rather than how it actually renders when you go back. That philosophical stance informs decisions about lighting, fog, and material response across the board.

At the world level, the Caribbean playspace has been rebuilt into a seamless open world. In the original, docking into major cities like Havana triggered loading screens and effectively segmented the world. Anvil now supports a large, continuous world, so the team removed those boundaries and streamed the entire experience. However, the footprints of cities in the original did not line up perfectly with the open-world shell, so the designers had to subtly reshape and tweak these spaces to make everything fit into a single continuous layout, including folding DLC islands into the same global map. Streaming systems in Anvil do the heavy lifting at runtime, but that work sits on top of a substantial world-integration pass.

The water and ship technology is clearly a point of pride. The original Black Flag water tech still holds up surprisingly well, which seems to have motivated the remake team to surpass it. Tessellation has been rewritten around a compute-driven, persistent mesh based on Intel's Combined Binary Tree work, replacing classic hardware tessellation. This allows fine-grained control over geometry density without re-tessellating from scratch every frame, and produces better-distributed polygons. On top of that, there is a new foam system that spawns and advects foam particles at wave crests over nested, clipmap-like grids, plus improved shoreline wetting and drying. Subsurface scattering through the body of waves has been reworked to recover that iconic bluish translucency, with parameters tuned so that wave thickness directly affects translucency and glow. Caustics have been redesigned to better conserve energy and respond to wave shape, darkening where fewer light rays concentrate and projecting moving wave shadows on the seafloor, with a simple shallow-water simulation in swimmer-accessible areas driven from depth buffer interactions.

Ray tracing is a key pillar, and the team has clearly focused on making RTGI and reflections viable across all current consoles and modes. Diffuse RTGI now runs in all console modes, including Series S, with the team aggressively reducing resolution - down to one-sixteenth in some cases - and then relying on improved denoisers, bilateral upscalers and temporal filtering to hide the loss of raw sampling density. According to Lopez, they were "really inspired" by SIGGRAPH talks by id Software (RIP) about how they implemented extremely low-cost RTGI in Doom, and retooled their pipeline accordingly.

Specular RT has also been brought down to quarter-res, supported by new anti-aliasing logic within the denoiser and additional temporal treatment. The RT stack remains hybrid: screen-space rays are used where they can fully resolve, with hardware rays filling the gaps and distant water falls back to cubemaps to avoid excessively long rays. In performance modes, the game leans on conventional SSR and cubemaps, with the RT featureset dialled in for each mode and platform.

Underpinning all of this is a highly granular, data-driven platform manager that controls hundreds, if not thousands, of tunables per platform, per graphics mode and even per gameplay context. Everything from RTGI resolution and BVH quality through shadow cascade update rates, hair strand activation distances, water tessellation, LOD ranges, cloth simulation tiers, skeleton update frequency and hanging prop simulation can be adjusted. The same system is used to differentiate ground gameplay, naval sections, menus and photo mode. Interestingly, vendors like AMD, Nvidia, Sony and Microsoft were given access to tweak profiles and suggest changes. On PS5, target internal resolutions are 1080p for performance, 1280p for balanced, and 1440p for quality, all reconstructed to 4K via an improved TAAU solution; PS5 Pro pushes PSSR and higher RT resolutions. The team notes that dynamic resolution scaling alone can't save you when micro-polygon counts rise this aggressively: they had to both improve TAA and raise baseline internal resolution to avoid geometric flicker, especially under weather-driven PBR modulation.

On PC, the build broadly maps to a fully uncapped variant of the PS5 Pro feature set, with higher RT resolutions, extended BVH ranges and boosted shadow fidelity - including contact-hardening shadows at the top end - and more generous deployment of strand hair and high-end water presets. RT options allow players to toggle diffuse-only or diffuse-plus-specular bundles, but specular cannot be enabled without diffuse, as the specular tracing is designed to lean on the diffuse solution for efficiency. RT BVH quality settings govern inclusion and distance, and all the major upscalers are supported. Shader compilation is handled through an internal logging and pre-warming system inherited from Valhalla and Shadows: QA playthroughs record all PSOs actually used by the game, and that curated set is then precompiled on first boot after driver or OS changes. The intent is to avoid both the combinatorial explosion of naive precompilation and the hitches associated with just-in-time compilation, and the team believes this has largely eliminated shader-related stutter - though they've not "yet" supported advanced shader delivery, hinting it might arrive in the future.

Ultimately, the Resynced development team consider a remake of this depth to be functionally equivalent to building a new game. Ships, faces, water, animation systems, stealth mechanics and the world structure have all been re-authored or significantly reworked.

One recurring theme is consistency: the dev team explicitly took criticism of Shadows' cross-mode presentation to heart and aimed for a much tighter visual alignment between Series S, base consoles and premium modes, even if that meant heroic optimisation on the memory-constrained Series S. Finally, they emphasise that the goal with Resynced is to deliver a Black Flag that feels exactly like the game players remember, but rebuilt with the fidelity, responsiveness and technical ambition expected of a flagship current-generation release.