Game Hair vs. Cinematic Hair

Hair in games and film sometimes end up with similar looks, but they diverge when it comes to acting requirements and render cost. In a film, the behavior callouts for a hair groom can vary widely, and self-collision is an issue that we will spend a tremendous amount of simulation time to avoid. Also, there’s nearly no limit to how many curves we’ll throw at a renderer to display a really nice-looking hairstyle. It’s costly, but these characters end up on very large physical media with very close cameras, and the high level of detail is necessary.

In games, the affordability of a final groom’s render is measured in milliseconds, not hours or days on a render farm. The team sizes for games are also generally smaller which makes it harder to devote a lot of RnD time to find a clever solution to something that probably won’t have a direct impact on gameplay. As a result, hair in games usually leans towards a combination of polygon cards and shader tricks in order to make sure a character’s hairstyle doesn’t drop the game below 60 fps. I sympathize a lot with those constraints because animated crowds need to be optimized like game assets if we’re going to get the job done in time.

Optimization for Real-Time Environments

The best way to get that kind of heavy content into a real-time environment is to cheat like a bandit! Replace those curves with polygon approximations, use shader tricks, textures and even lighting to approximate the heavy version of the asset. Plan for the final look/behavior, and reduce, reduce, reduce.