Assassin's Creed Black Flag Resynced Pushes PS5 Limits, Ubisoft Reveals

Ubisoft developers revealed the extensive technical efforts behind the upcoming Assassin's Creed Black Flag Resynced, stating they pushed the PlayStation 5 console to its absolute limits. Technical Director Jussi Markkanen and Technical Architect Nicolas Lopez detailed how the project is a significant technical reimagining rather than a simple remaster, aiming to extract maximum performance from current-generation hardware.

"We really squeezed the PS5 as much as we could," Lopez stated, suggesting that further advancements on existing platforms might be challenging for future Assassin's Creed titles. The team focused heavily on enhancing ray tracing performance, implementing Ray-Traced Global Illumination (RTGI) across all consoles and game modes. They also significantly increased scene density and crowd counts beyond what was achieved in Assassin's Creed Shadows, while ensuring stable frame rates for each performance mode.

The new release is built on an upgraded version of the Anvil engine, utilizing the foundation from Assassin's Creed Shadows. However, nearly all original game assets have been remade to support a modern Physically Based Rendering (PBR) pipeline. The original Black Flag assets were not designed for features like ray tracing or micro-polygon detail. To achieve the desired visual fidelity, artists rebuilt meshes and materials from scratch, adhering to the original art direction but incorporating dense geometry and PBR-correct materials.

Revamping Gameplay Systems and Character Models

Scene density and crowd complexity saw a major overhaul. The city of Havana, a highlight in the original, has been reworked into an exceptionally dense environment, reportedly doubling the asset density and crowd count compared to AC Shadows. Optimizing for reasonable frame rates within the existing level design and quest structure of Black Flag presented a considerable challenge. The solution involved implementing systems-level scalability across both the CPU and GPU.

Gameplay systems also received substantial modernization. Stealth mechanics have been overhauled with a "crouch anywhere" feature and improved light/shadow stealth, moving away from the original's reliance on fixed stalking zones. This required adapting old level designs to a new stealth model that reacts to illumination. Destructible environments are another key addition, with small environmental elements now breakable, inspired by technology used in AC Shadows, adding gameplay opportunities like pushing enemies through clutter.

Character models also underwent significant upgrades. The strand-based hair system from Assassin's Creed Shadows returns, now better optimized and more widely implemented, including for crowd characters. The team made specific adjustments to the shading and lighting for blonde hair, which is more prevalent in Black Flag's setting. Facial animations aimed to preserve the original iconic motion capture performances while utilizing more detailed face meshes, complex shaders, and layered deformation. Re-targeting old motion capture data to new rigs only achieved partial results, necessitating a multi-stage transfer pipeline and extensive manual artist work to restore nuance, particularly around the mouth and eyes.

Reconciling the look of the original seventh-generation title with the new PBR and ray-traced pipeline was a central rendering challenge. Developers aimed for faithfulness to the original's intent and memory rather than a literal implementation. Decisions about lighting, fog, and material responses were guided by how players remember Black Flag looking. This approach ensures the remake evokes the nostalgic feel of the 2013 game while benefiting from modern graphical techniques.

The Caribbean world has been rebuilt as a seamless open world, removing loading screens that previously segmented major cities like Havana. The Anvil engine now supports a large, continuous world, allowing for a fully streamed experience. Designers meticulously reshaped and tweaked city layouts to fit seamlessly into the single continuous world, integrating DLC islands into the global map. The water and ship technology represents a particular point of pride, with the remake team aiming to surpass the surprisingly robust water tech of the original. This includes a rewritten tessellation system, a new foam system for wave crests, improved shoreline wetting, and reworked subsurface scattering for wave translucency. Caustics were redesigned for better energy conservation and responsiveness to wave shapes.

Ray tracing is a foundational element, with a strong focus on making RTGI and reflections viable on all current consoles. The team aggressively reduced rendering resolution for diffuse RTGI in some cases, relying on advanced denoisers, upscalers, and temporal filtering to maintain visual quality. According to Lopez, the development was significantly inspired by talks from id Software at SIGGRAPH.