HairDeck: Animation-Ready Stylized Hair Cards from a Single Image

HairDeck. Animation-Ready Stylized Hair Cards from a Single Image. By Yuze He and five others, from Tsinghua University, Carnegie Mellon University, and one other institution. Published on the twenty-ninth of October.

Stylized characters in games and avatars get their hair from hair cards: ribbons placed by artists, whose geometry is the visible hair, animated by spring bones. Existing image-based methods produce either realistic hair or a single fused mesh, neither of which is a set of cards. CHARM, the only generator of stylized hair cards, decodes a hairstyle autoregressively, as a long sequence of control points. A hairstyle in that framing is one long string, produced token after token, even though the cards that make it up are separate pieces. And a usable asset needs more than shape: it needs the bones that make the cards move.

HairDeck starts from an observation. A card hairstyle is an unordered set of artist-defined primitives, so it can be generated as a set. Each card becomes a single token, and a set diffusion transformer denoises all the cards together, instead of emitting them one point at a time.

From a single image, HairDeck generates both the cards and the spring-bone chains that drive them. The result is an animatable asset that exports to ready-to-use downstream formats. That closes the gap between a generated shape and something a game or avatar pipeline can use directly: the output is already in the form artists build, cards plus the spring bones that animate them, rather than a mesh that would still have to be converted and rigged.

On CHARM's own test set, HairDeck lowers Chamfer distance by forty-four percent, cuts card-orientation error by more than half, and runs thirty-three times faster. Working from single images, it outperforms CHARM, image-to-3D pipelines, and strand-based methods.

The gain rests on matching the representation to the object. A hairstyle made of cards has no natural order, and treating it as a set, one token per card, is what lets the whole thing be generated at once and rigged for motion.