---
title: 'Assassin''s Creed IV Black Flag Resynced: A Technical Deep Dive'
source: 'https://youtube.com/watch?v=23SXKKfm4NA'
video_id: '23SXKKfm4NA'
date: 2026-07-11
duration_sec: 893
---

# Assassin's Creed IV Black Flag Resynced: A Technical Deep Dive

> Source: [Assassin's Creed IV Black Flag Resynced: A Technical Deep Dive](https://youtube.com/watch?v=23SXKKfm4NA)

## Summary

Assassin's Creed IV Black Flag Resynced is a full-on remake rather than a simple remaster, featuring completely rebuilt assets, advanced ray tracing, and enhanced water physics. The game runs on the modern Anvil engine, delivering a visually stunning experience that surpasses even Assassin's Creed Shadows in environmental density and lighting quality.

### Key Points

- **Remake vs Remaster** [00:00] — Black Flag Resynced is a full remake with all-new environmental assets, PBR properties, and micro-polygonal detailing, not just a remaster.
- **Environmental Density** [01:40] — Havana's density exceeds Kyoto in AC Shadows due to MicroPolygon technology and the team's better understanding of performance limits.
- **Interactive Environments** [02:11] — Environmental props can be smashed and broken, similar to AC Shadows.
- **Character Models** [03:22] — Character models feature advanced skin shaders, subsurface scattering, and realistic cloth. Friend-based hair is used, inherited from Shadows.
- **Lighting Evolution** [04:44] — Resynced uses RTGI in all modes on all consoles, replacing the original's baked probe-based solution. This required significant optimization inspired by id Software's Doom: The Dark Ages.
- **RTGI Optimization** [06:04] — Ubisoft adopted a 1/16th resolution RTGI setup for performance mode on PS5, similar to id's approach, enabling 60 FPS with good visual quality.
- **RT Reflections Expansion** [07:15] — RT reflections now appear in performance mode on PS5 Pro and in balance/fidelity modes on PS5 and Series X, using quarter-resolution tracing.
- **Water Rendering** [09:32] — Water tessellation uses compute shaders instead of hardware tessellation, with new foam simulation, improved scattering, and screen-space fluid simulation for shallow water.
- **Seamless Open World** [10:41] — Loading screens when docking at cities have been eliminated, requiring conforming island maps to the world map.
- **Gameplay Changes** [11:19] — First-person modern-day sections and tailing missions have been removed. Improved parkour, crouching, and difficulty options have been added.
- **Console Performance** [12:42] — PS5 has three modes: fidelity (30fps, 1440p), balanced (40fps, 1280p), and performance (60fps, 1080p). DRS often runs below targets but image quality is good.

### Conclusion

Assassin's Creed Black Flag Resynced is a technical triumph and one of the best-looking remakes, leveraging modern hardware for a visually rich and polished experience.

## Transcript

Assassin's Creed IV Black Flag is a fondly remembered title. Released at the very start of the PS4 and Xbox One console generation, this seafaring title let players live out a pirate fantasy, voyaging the Caribbean and engaging in ship battles.
But its graphics tech, which was designed around the PS3 and Xbox 360 systems, hasn't aged as well, so Ubisoft has taken the opportunity to visually remake the game with Black Flag
Resynced, the new version of the game running on the modern Anvil engine. I've been playing the game over the past week to check it out, and I was able to speak to the game's technical director and a rendering architect to explore the game's visual features
in more depth. So what makes Resynced tick, and how does it improve over last year's excellent Assassin's Creed Shadows?
Black Flag Resynced amazed me. Going in, I expected more of a refurbishment of the original game. A lot of developers have gotten mileage in remastering efforts by reusing much of the original work.
But that's not the case here. This is something closer to a full-on remake than a remaster, and that starts with the assets. Just about every environmental asset has been remade here, with PDR properties, luxurious micro-polygonal detailing, and new artistic treatments to take
advantage of the inherent density that night-gen consoles and modern PCs can offer. You'll notice in these comparisons that not everything matches one-to-one, but the reinterpretations seem sensible and give the world the density befitting current gen systems. Ubisoft told me that
the environmental density in areas like Havana should significantly exceed similar areas in Assassin's Creed Shadows like Kyoto. In part, this is because the team's MicroPolygon technology was being developed alongside Shadows, and environmental artists needed to err on
the conservative side to avoid performance bottlenecking in that game. For ReSync, they They had a better idea of the limits they would end up with, and were able to deliver a substantially richer world than any prior Assassin's Creed title.
In part, it also came down to the denser quality of coastal cities like Havana, which are more tightly packed than the wide streets of Kyoto. The environmental assets have also become interactive. Just like in Shadows, environmental props can be smashed and broken into bits and pieces
as you collide with them. Loading these games up in wireframe view is very revealing. Here's Kingston in the original Black Flag, running bereft of most writing detail, so we can focus on the assets.
For a seventh-gen game, this is good stuff. Houses are chunky but mostly look fine, barrels seem suitably rounded, and characters look serviceable enough. Black Flag did have versions for PC, PS4, and Xbox One, but it was sculpted around the
limits of Xbox 360 and PS3, and often looked apart. But moving on to Resynced, we see a dramatic increase in the amount of polygonal detail conveyed in the scene. Perspiration is a big part of the picture here, as the game extensively uses this technique
to enhance ground geometry as the camera nears. Visually speaking, Resynced is virtually a full-on remake, and that's for the best. The character models are similarly dense. Expect redesigns and linings for current-gen paradigms, with advanced skin shaders, excellent
subsurface scattering, and realistic leather and cloth. Friend-based hair is also used, which is inherited from Shadows. This is featured on characters throughout the game, including on pedestrians in the open world, depending on the graphics mode and distance from the camera.
The developers did have to iterate and improve the appearance of their shading on blonde hair which didn come up much in the Japan set AC Shadows But Ubisoft decided to take a more measured practical approach when it came to cutscene animation
Black Flag's original performances are well known, so they retained the performance and motion capture data to build Rethinked. Wrapping the old mocap data onto the new models didn't work so well, however,
with vastly enhanced geometry, shaders, wrinkle maps, and other improvements causing issues. issues. They did improve this system over the course of the game's development, but it sounds like the finished game's relatively polished look is a large part of the testament to a lot of
manual tweaking from artists. Likewise, gameplay animation is a mix of old and new. Some animation work has been inherited from the original, and there's new work as well. Probably the most obvious change lies in the adoption of Ubisoft's Motion, a cloth animation system, giving Fabric
the stimulation that responds dynamically to character movement. That applies to ship sales as well which also use motion. Lighting has evolved massively, both over the original game and also over AC Shadows.
The original game used pretty sophisticated tech for GI at the time, relying on a partially baked solution that used probes, which were baked out for multiple times of day and blended to produce the end result. That was combined with ambient occlusion to provide a reasonable approximation of diffuse
indirect lighting detail. There are clear limits to this approach. Camera occlusion caused SSAO detail to disappear, for instance, and lighting data was coarse and lacked some directionality, but it was an improvement over prior AC titles, and represented
Ubisoft's first proper stab at a GI solution in AC games. Recent has a sumptuous, lush appearance in contrast, with rich lighting detail in every preface. Like a lot of other current generation games, lighting has a bit of a heady look with some
over-occlusion, but it's also a subjectively very pleasing appearance. feels anchored in the same lighting volume, with no real bleeding through walls or other common rasterized bugbears.
That's because Resync is using RTGI here, but unlike Shadows, it's using RTGI in all modes across all consoles. A probe-based offline solution is still in the game as an option for PCs, but on consoles
and mainstream PC hardware, we've completely moved on to RT, even for Series S. Getting there required a lot of hard work. The developers were inspired by id Software's work on Doom the Dark Ages and their extremely
performant RTGI solution, which took around 2 milliseconds to run on console hardware. Id's RTGI notably ran at 1 16th res, or 1 quarter on each axis, but retained excellent
visual quality. On consoles, Ubisoft's RTGI was 1 quarter res, which required a much higher processing outlay to run, foreclosing 60 FPS performance on base consoles. To achieve the FTS performance then, Ubisoft would need to adopt a similar 1.16th res setup.
To give you some idea of the challenge here, here's the raw diffused RTGI tracing at 1.16th res, 1.25th res, and full res, all operating without temporal upscaling or denoising. The diffused albedo here is set to pure white, so the tributyre doesn't get in the way.
1.16th res looks like grainy soup here, descending almost into abstraction. The same white albedo setup, but with upscaling denoising applied, reveals just how effective the game's RT filtering works in practice.
1.16 Threads has a slightly less defined appearance, but broadly looks about the same as the high resolution settings. There is a slight bit of flickering here at 1.16 Threads, but in the final game with full texture detail, it's less likely to be noticed.
PS5 uses this 1.16 Threads setup then in performance mode. Similar improvements enabled an expansion of the game RT reflection technique to more Previously only used in balance and fidelity modes on PS5 Pro it now also in play in performance mode on Pro and in balance and fidelity modes on the PS5 and Series X Again the developers have
cut down resolution from half-res on PS5 Pro previously to quarter-res. With no denoising or temporal upscaling, the results look fairly awful, but once Ubisoft's temporal magic is applied, the end result looks perfectly good using a
Resolutions need to be higher here as specular information tends to be much higher frequency than diffuse GI. The game still does some tracing in screen space, which is noticeable in this shape here
and when looking at the system view. At a distance, the game's BDH is cut off, so the game falls back on tube maps and screen space tracing. Series F, plus PS5 and Series X in their performance modes, eschew RT reflections entirely leaving
on tube maps, plus screen space reflections instead. Amusingly enough, the original Black Flag was an early adopter of SSR, albeit in a noisy and low-detail form. More modern SSRs don't produce perfect results, but they're still a big step up over these
early efforts. Elsewhere, they leaned on less-valuable techniques, or QMAPs. Interestingly, the recent developers admitted that one of the hardest challenges they had in this whole process was balancing fealty to the original game with adherence to PDR
principles. the first game was built with much more primitive lighting and rendering tech that was heavily artist-driven, while modern games are artist-guided but rely on simulation. In the end, the team chose to honor the intention of the original game, without being wedded to the exact look
of the original, which wouldn't make sense to replicate in the new Anvil engine. Black Flag broke new ground with its seafaring structure, a first for any Assassin's Creed title.
The game had a semi-open world structure with few loading screens, and permitted you to sail the high seas as you saw fit travelling to various ports. Obviously that meant that water was a big part of the game, and Black Flag had excellent water rendering for the time.
The engineers I spoke to said that black-slides water was the visual system from the original that aged best, which only heightened the challenge for resync. The largest change here is that the water tessellation has been reworked and enhanced.
It's no longer using hardware tessellation, instead relying on compute to build a persistent tessellated mesh to convey the broken appearance of the open sea. A new system simulates foam, which prominently appears when waves crest and decays over time.
Scattering in the water has been improved, which you can notice when the sun shines into vertical wave faces. Water caustics still align to animated textures, but more realistically darken according to the shape of the waves above.
Plus shallow water now uses a fluid simulation that works in screen space to simulate the fluid movement at the water's surface around moving objects. The water in Resync is a definite visual highlight. I do think that a lot of the visual credit comes down to the enhanced reflections technology,
which catches the light perfectly across the water's surface. But a lot of thought has been expended on making the water look as pleasing as possible. Finally, Resync takes the opportunity to revise the game's core gameplay to make it fit better with modern audiences.
The largest structural change comes down to the consolidation of the open world into one seamless whole. Black Flag was an open world game, but docking at nature's cities did require a loading screen, and that's been eliminated in this new version.
That required some work conforming the island maps and world map as they didn't totally march before. Basic movement has been revised with improved parkour and the player can now crouch anywhere Combat has been tweaked to come closer to more recent AC titles Difficulty options have also been added I can speak to the whole range of gameplay changes and additions because there are a lot of them but the game does feel suitably modern in a way the original does not
Perhaps somewhat controversially, the developers have also decided to remove the game's first person modern day absurdo sections, in line with other modern Assassin's Creed titles. These sections tended to dry, so I'm personally fine with their removal.
I'm told the game does feature new modern-day content later on, but I didn't experience any of them in my time playing. Plus, the game's annoying tailing missions seem to have been altered or removed and replaced
with alternative content, which seems like an upgrade to me. Overall, I think Black Flag Rethinked is a major tasteful success, at least as I've experienced the game so far. I think the game looks sort of like you might remember Black Flag looking, with a similar
feel and art direction, but it's been evolved wildly. meet or exceed modern expectations for a AAA game. It's a truly beautiful experience and ranks as one of the most effective remakes I've seen, taking excellent advantage of PS5 hardware.
And the developers working on the paddle seem to think so too. One of them told me that they felt like they had squeezed the PS5 as much as they could and that topping the game significantly would take a lot of work. It seems like being built on top of more mature technology helped,
though the devs were still surprised by the amount of optimization they managed to achieve. In particular, the ray tracing implementation was flagged as being highly optimized and performant, though some quality wins may remain for future titles.
I'd be remiss if I didn't close out with a bit of console performance. I want to save my extended thoughts for an upcoming console comparison piece, but I did play a fair bit on PS5. It even has three modes. A fidelity mode that targets 30fps,
a balanced mode at 40fps, and a performance mode at 60FPS. The game has pretty good image quality, relying on an evolved version of Anvil's TAAU for upscaling. Performance mode has a bit of a rougher output,
but it still looks fine enough for a 60FPS console title. I was told the DRS resolution targets for each mode are 1080p in performance mode, 1280p in balance mode, and 1440p in fidelity mode, though in practice the game often runs a bit
below those figures in my samples. But the developers reckon that typical resolution spheres should be higher than in shadows, despite the enhanced ray tracing, and I'm inclined to agree based on my test. That's also reflected in generally very good image quality for an ambitious console title.
The biggest future-level excision here comes down to reflections. RT reflections don't make the cut in performance mode, but are part of the game in balance and quality modes. But I think the RTGI is most critical here, and it survives just fine in performance mode.
is also simplified in performance mode and there are some 4D's writing concessions in that mode as well. Performance is generally stable across the board in all three modes. In early areas the game hits a locked framerate in gameplay, though I didn't have too much time to put the game through the
ringer on the day one patch. I don't think framerate should be a big concern here at all though. For users on PS5 consoles, the game should be an excellent experience and the limited space as seen on other platforms is also promising. It seems like a very polished game,
ditching some of the performance mode compromises that typified AC Shadows. We'll explore what that means across all console platforms and follow-up content, but every indication so far looks good. So, Assassin's Creed Black Flag Resynced is an unexpected technical triumph.
This is one of the best-looking remakes around. If you enjoyed this video, please like, subscribe, and press the bell for YouTube notifications. Check out the Patreon at patreon.com slash digitalfoundry for exclusively access to content and to get in touch through social media.