Ubisoft chose some interesting timing for its showcase of the Anvil engine and the Atmos system.
Ubisoft has launched a behind-the-scenes video series focused on the Anvil engine, the technology primarily used to build the company’s Assassin’s Creed games. The latest entry in the franchise, Assassin’s Creed Shadows, brought several technical innovations with it, which made the game feel like an impressive showcase at launch. Through this behind-the-scenes series, Ubisoft aims to highlight the most important additions made to Anvil, starting with Atmos.
Atmos is Ubisoft’s physics-based weather simulation system built into the version of the Anvil engine used for Assassin’s Creed Shadows. Instead of relying on prebuilt or downloaded weather states, it simulates atmospheric conditions in real time and propagates physical variables such as temperature and humidity to determine weather outcomes dynamically: whether it rains, whether the wind picks up, or whether the sky remains clear in a given area.
At its core, Atmos runs a fluid simulation that drives multiple interconnected systems at once. Wind simulation is the central force, since it feeds cloud formation, precipitation, and everything else. At the same time, the team also created a spray particle system, a dynamic wind simulation with collision that physically moves particles through the environment. The key point they stress is that wind data is shared across all systems, so rain, character clothing, hair, foliage, sound, and lighting all respond coherently to the same underlying simulation instead of reacting independently from one another.
According to the developers, Atmos affects more than just visuals. It also influences NPCs, animals, crowds, and gameplay opportunities in real time. Weather transitions happen seamlessly and without loading, something the team describes as unprecedented for the Assassin’s Creed franchise. In the video, Ubisoft noted that player feedback and reviews suggested many people avoided fast travel because they did not want to miss the dynamic weather shifts that occur during overland travel. The team describes Atmos as a conductor. It does not directly control every system, but it orchestrates rain, lighting, sound, and particles into one coherent whole. Coherence was the goal, as one of the foundations of immersion: the wind blows rain onto character models, moves clothes, ruffles hair, and all of it is driven by the same simulation data.
According to the video, this is only the beginning. Anvil continues to push the boundaries of immersion and open-world design for the benefit of players. That said, the timing of this behind-the-scenes series is a little odd. Assassin’s Creed Shadows has already been pushed well into the background, and Ubisoft has confirmed there are no more DLC plans after Claws of Awaji. One possible explanation is the long-rumored Assassin’s Creed Black Flag Resynced, which uses the same engine and is therefore expected to include all of its features, including Atmos. Rumors say the remake may be announced soon.
Source: WCCFTech
