Dev Blog: Creating Believable Hair and Fur

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rise_of_the_tomb_raider_dev_blog_creating_believable_hair_and_fur

Michael Svymbersky, Character Artist

Without a doubt, hair is among some of the hardest things to get right in computer graphics. CG hair should unify the character and not be noticeably distracting to the viewer/player. It’s a technically and artistically challenging endeavor as we never want hair to look like a wig but that it belongs to the character. It’s an important thing to get right because creating believable hair can go a long way in enriching particular details about a character’s background and/or place in the world. As such with Rise of the Tomb Raider we spent a great deal of effort to bring our characters and animals alive by creating the appropriate hairstyles and fur patterns.

When creating hair and fur for all of our non-player characters and animals we use the method of Alpha Card creation and arrangement. Alpha Cards are geometry planes that have the shape of individual clumps of hair. Applied to these geometry planes is a texture that can be broken down to its most important parts: the Color map and Alpha map.

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The color map, is a painted/photo-sourced texture, while the Alpha map dictates transparency. The color black will tell the texture to render invisible while the white color will stay visible. With the texture and arrangement of cards, we can nail the appearance of hair.

The shader tells our game engine how to render the object. It will use all the textures we input to control the highlights and lighting conditions that are in effect.

The arrangement of these alpha cards are the key to this whole process. Many artists have different workflows, but the most tried and true method is the manual placement and evaluation for each individual Alpha Card. We place the cards down to fill out the character and to add the appropriate silhouette changes. Regardless of the content that we are creating, the same techniques are applied across the board for animals, character hair, beards and props.

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As demonstrated on the bear, we are manually placing the Alpha cards on the model, creating the texture and adjusting the shader for correct highlights. It’s a very back and forth process and we go through multiple iterations before achieving the final look.

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Hopefully this gives you a little peek behind the scenes for how we approach hair and fur. We believe that it’s these little nuances that achieve a believable presence and help ground these characters into the Tomb Raider world. While it’s an artistic and technically challenging endeavor, it is also one that’s very rewarding to see in Rise of the Tomb Raider.

Michael Svymbersky 
Character Artist, Rise of the Tomb Raider