Anvil, previously known as Scimitar, is Ubisoft's proprietary game engine. The engine was later renamed to AnvilNext, followed by AnvilNext 2.0.
Claude Langlais, the Technical Director of Ubisoft Montreal, has stated that Autodesk's 3ds Max is used for the environment and ZBrush is used for the characters. It uses Autodesk's HumanIK middleware technology for positioning the hands and feet of characters in the environment.
It used the Scimitar name for Assassin's Creed, Prince of Persia (2008), and Shaun White Snowboarding. It is named after the scimitar weapon, which commonly appears in the Assassin's Creed and Prince of Persia franchises.
For the Assassin's Creed II version of the engine, Anvil, there were many technical improvements and additions. Cloth physics were improved, vegetation technology was borrowed from Far Cry 2 and a night and day cycle was added.
The engine was renamed to AnvilNext when it received a large update in 2012. The first game to use this updated version of the engine was Assassin's Creed III.
In 2014 yet another large update to the engine happened with Assassin's Creed Unity.