Aurora Engine

BioWare's  Aurora Engine was used to create The Witcher computer game. It had been rewritten (around 80%) to utilise the latest version of DirectX 9. The new engine's main feature is a brand new rendering system responsible for realistic visuals. Vertex and pixel shaders have been implemented, allowing magical swords to glow subtly in the dark, as well as the eyes of some creatures. These shaders have also allowed for the implementation of numerous stunning full-screen effects, like witchers' night vision.

A new version of the rewritten engine was planned for The Witcher 2: Assassins of Kings, however, it was scrapped in favor of an entirely new engine developed internally by CD Projekt RED.

Additions
New functionality significantly increases the realism of the environment:
 * The 24h passage of the day and night cycle will enable the player to witness beautiful sunrises and sunsets, marvel at the starry sky, or fight in the moonlight. The time of day is not only cosmetic, but also affects gameplay, e.g. some creatures can only be hunted down at night.
 * The game features realistic weather patterns, down to such details as the delay between lightning and thunder. The player can get caught in a sudden torrential downpour, with the raindrops falling realistically on everything they hit.
 * The character's dynamic shadows have been softened so that no more sharp or shattered edges show up.
 * Realistic physics make any pushed object roll across the ground; killed enemies fall in a realistic manner, largely thanks to rag doll physics; even decapitated heads behave according to the law of physics.
 * Real-time fighting instead of a turn based system makes skirmishes eye-catching and spectacular. Graphics effects, like blood splattering on various surfaces (walls, floors), and slowed down cinematic finishers.
 * During combat, a special character expression system with appropriate voice acting skirmishes all the more engaging and realistic.
 * Improved EAX in-game sound effects will complement the visual aspect of the game.