NVIDIA HairWorks in the Witcher 3
HairWorks brings a new level of fidelity to the gameplay experience of The Witcher 3: The Wild Hunt by producing stunning shading and dynamic motion with thousands of simulated hairs on multiple characters, simultaneously on-screen. Hair and fur even react to forces and spells for yet another level of immersion. The Witcher 3 uses HairWorks to create dynamic hair and fur on dozens of characters in the game.
The main character, Geralt of Rivia, features HairWorks on all of his hairstyles throughout the entire game. To accomplish these hairstyles, our team worked closely with CD PROJEKT RED artists and engineers to create new HairWorks features, specifically for long hair. These newly developed features were all added to the latest HairWorks release, and include advanced stiffness and bending controls to aid with intricate styling, and enhanced diffuse, specular, and glint controls to help with more realistic shading. Geralt’s hairstyles range in complexity from shaved sides and various beards, to long flowing elements, such as his long hair and half-tied pony tail, to tied back elements like his pony tail.
A unique feature that Geralt has that no other character has, in any game to this point, is simulated hair that can change states. Geralt’s hair gets wet when he enters water; his hair’s physical and shading properties change to imply that it is wet. This wet state matches the wardrobe elements that also receive a wet shading aesthetic.
|Dry Hair||Wet Hair|
Aside from Geralt’s hair, dozens of monsters and animals make use of HairWorks. Horses are the most common example; all of the horse manes in The Witcher 3 are composed of HairWorks. They are an interesting example of hair since they are just long enough to not be considered fur. The movement of a horse’s head and neck creates excellent motion to show off the simulation.
Other monsters and animals also have varying hairstyles. Godlings, and katakans have long, flowing hair-like features while wolves and bears have short hair and nearly full-body coverage. Meanwhile, griffins, lycans, and bies have medium–length, patchy fur.
The average hair strand count for characters is between 10,000 and 40,000 strands per character at standard gameplay distance. When Continuous LOD kicks in, which allows for hair count and thickness to be smoothly adjusted based on camera distance, hair counts can reach over 125,000 strands.
The content pipeline for The Witcher 3 facilitated rapid iterations, allowing for the creation of these many dozens of HairWorks characters. Off-the-shelf growing tools from 3D Studio Max were used to create a series of guide curves, which can then be exported to the HairWorks viewer tool for tuning Physical, Style, Graphics, and LOD elements. Lastly, assets can be brought directly into the game engine for final polish. It can take anywhere from a few hours to a few days to get a creature polished up with HairWorks, depending on its complexity.
There are over forty HairWorks characters in The Witcher 3, some of which have multiple HairWorks assets. For instance, the katakan has two hair assets - one for its short fur and one for its long beard elements. The katakan took about two days to get a solid version of the character with HairWorks. From there, it takes a couple iterations with the art director to completely polish the look and feel of a HairWorks character. Geralt’s hair is also composed of multiple hair assets per hairstyle.
When it is all said and done, there will be hours upon hours of hairy moments in The Witcher 3: Wild Hunt’s epic world - only made possible through HairWorks.