During the Game Developers Conference CD Projekt RED Lead Engine Programmer Balazs Torok held a presentation titled "The Witcher 3: Enabling Next-Gen Effect Through Nvidia Gameworks," focused on the implementation of hair and fur in the game.

The slides of the presentation have now been made available, and we learn quite a few elements about the Hairworks technology, supplied by Nvidia, and we also get to see quite a few work-in-progress screenshots.

CD Projekt implemented it because the game is an RPG, so characters and monsters are very important, and hair/fur is a prominent feature. The integration with CD Projekt's RED Engine was done in a few days thanks to the help from Nvidia.

In order to fully implement it, two parameters had to be added to fur, in the form of waviness and clumping. Below you can see normal straight hair, then waviness added, then clumping and finally both mixed.

The implementation involves creating a growth mesh from the graphics mesh, where the hair grows from. The graphics mesh basically is like a shaved animal/head. Most old generation models instead use stripes of polygons with hair textures of them to simulate fur. Those had to be removed in order to implement the new hair.

Below you can see two work in progress pictures of a wolf created with Hairworks.