Hair Cards and Facial Topology Guide

1. Start from character requirements

Lock camera distance, hairstyle silhouette, animation range, and performance budget before retopology. Facial topology must support the expected speech shapes and brow compression; a cinematic close-up needs different density from a distant NPC. For hair, gather front, profile, back, and top references. Mark the hairline, part, crown, clumps, and areas where ears or cheeks must remain readable.

2. Build expression-led facial loops

Route loops around the mouth, eyelids, nasolabial region, and brows according to muscle motion rather than a decorative grid. Keep enough radial segments for lip corners and eyelid closure, while moving poles away from creases that fold strongly. The jaw and cheek need room to slide without collapsing volume. Test topology with a small expression set before sculpt detail obscures structural problems.

3. Construct hair cards by layer

Begin with broad foundation cards that cover the scalp and establish volume. Add medium clump cards that describe flow, then sparse breakup cards for silhouette variation. Each card should follow strand direction so the texture tangent and anisotropic response are coherent. Avoid stacking many nearly coplanar cards: they increase overdraw, flicker, and sorting risk without meaningfully improving the hairstyle.

4. Texture and material settings

Pack opacity with sufficient edge padding and mip-safe coverage. Keep color variation subtle across clumps; strong randomization looks noisy at distance. Use alpha clipping for stable game silhouettes when soft transparency is unnecessary, or alpha blending only where the renderer and sorting plan support it. Verify normals, tangents, two-sided shading, and backface response. Test the material under bright rim light, where card boundaries become easiest to see.

5. Skinning and collision constraints

Bind roots strongly to the head or nearby joints and allow tips to follow secondary bones only where motion is desired. Keep cards clear of eyelids, lips, and brows through the complete facial pose range. Long locks may need dedicated chains, cloth, or simplified collisions; do not let face joints accidentally pull scalp cards. LOD changes must preserve the part line and outer silhouette even as internal cards disappear.

6. Decision example: shoulder-length hero hair

For a shoulder-length hero seen from chest-up, choose broad opaque foundations at the scalp, blended transition cards around the hairline, and larger clumps down the sides. Reserve thin flyaways for the outer silhouette. Place facial loops for full blink, smile, lip purse, and jaw-open tests. If cheek cards intersect during a smile, reshape or rebind the clump before adding simulation complexity.

7. Diagnose common failures

Visible scalp gaps usually mean the foundation layer lacks overlap or mip levels erode opacity. Sparkling edges suggest poor alpha coverage, insufficient padding, or unstable temporal sampling. Dark cards may have flipped normals or incorrect two-sided lighting. Facial pinching points to a pole, sparse loop, or weight transition in a high-strain zone. Hair crossing the eye during expressions is a clearance and binding failure, not a texture problem.

8. Evidence checklist and multilingual workflow table

Deliver front, side, back, and top renders plus a scalp-only view, overdraw visualization, LOD comparison, and material close-up. Include blink, smile, jaw-open, and brow poses with hair enabled. Record triangle count, card count, transparency mode, texture resolution, and secondary-motion ownership. Use the shared terms below in review notes so card-level and hairstyle-level requests remain distinct.

Related production references