How Unreal Engine Artists Build Curly Red Hair That Moves

Red hair is notoriously hard to recreate convincingly — in real life and in digital character work. An Unreal Engine breakdown shared by artist Taehun Kim, centred on a real-time MetaHuman “Red Hair” character, offers a surprisingly useful lens on what makes curls look believable: structure, consistent patterning, and movement that respects how hair actually behaves. While the project lives firmly in the world of 3D art, the principles behind it echo what UK stylists talk about every day: curl definition, light reflection, density, and how hair moves when you turn your head.

In this article, we translate the key ideas from Kim’s process — including building “hair cards” for a curly style and using MetaHuman animation keys — into practical insights for anyone curious about why some curls (and colour) read as real on camera, and what you can do to get closer to that finish in everyday styling.

Why curly red hair is a realism test (on screen and in real life)

In photography and video, copper and auburn tones can swing quickly between vibrant and flat depending on lighting, while curls can look either beautifully dimensional or oddly “blocky” if definition and distribution aren’t right. Digital character artists face similar challenges: red hair needs a convincing response to light, and curls require a coherent pattern across the head so the viewer’s eye reads it as natural.

Kim’s Unreal Engine project highlights two core realism issues that translate neatly to everyday hair knowledge:

• Light behaviour: Red hair reflects light in a way that can exaggerate shine on some strands while leaving others looking dull. In digital art, this is handled through shading; in real hair, it’s influenced by cuticle condition, styling products and the direction hair is set.
• Curl continuity: Curls rarely sit in identical ringlets across the whole head. Believable texture comes from controlled variation — in strand size, direction, and density.

For UK readers who regularly style natural curls or heat-set waves, the takeaway is refreshingly familiar: definition isn’t just “more product” — it’s also placement, pattern, and how the hair is allowed to dry and move.

Hair cards, curl pattern and the digital equivalent of a good cut

In Kim’s breakdown, one of the standout technical steps is creating hair cards — flat polygon “strips” textured to look like groups of hair strands — arranged to build a full curly style. It’s a standard approach for real-time hair in games and virtual production because it balances realism with performance.

If you’re not a 3D artist, think of hair cards as the digital equivalent of constructing a hairstyle in intentional sections: instead of trying to make every single strand perfect, you build believable groups in a way that reads well from typical viewing distances.

That idea mirrors how curls tend to look best when they’re shaped strategically:

• Strategic grouping: Curls often look more natural when you encourage consistent curl clumps (for example, by styling in sections and raking/praying hands through).
• Controlled variation: Even when the overall pattern is coherent, the most believable curls include subtle differences in clump size and direction.
• Silhouette matters: In 3D, the outer shape is key; in real life, a curl-friendly cut (often with thoughtful layering) can stop hair forming a heavy triangle and help curls spring evenly.

Many curl specialists in UK salons focus as much on the shape as the product routine, because the cut determines where weight sits — and therefore whether curls have room to form.

Movement and MetaHuman keys: what animation teaches us about styling for “life”

Kim also discusses using MetaHuman keys to animate the character. In the MetaHuman ecosystem, key controls help drive facial and performance animation reliably, keeping expressions and head movement consistent in real time. Hair then has to “play nicely” with that movement: if the hair shape doesn’t respond believably, the whole character can feel artificial.

In everyday hair terms, this is the difference between a style that looks good in the mirror and a style that looks good in motion. If you’ve ever loved your curls at home only to find them collapse or frizz after a brisk walk to the station, you’ll recognise the challenge: hair has to withstand movement, humidity shifts, and friction from coats and scarves.

Practical ways to style with movement in mind include:

• Set the curl, then leave it: Once curls are formed, touching them repeatedly can disrupt clumps and increase frizz. Many stylists recommend letting hair fully dry before gently scrunching out any cast.
• Balance hold and softness: A light-to-medium hold styler can help preserve definition during the day, particularly in damp UK weather, without making hair feel crunchy once scrunched out.
• Plan for friction: If you’re wearing woolly scarves or high-collared coats, consider loosely pinning the front sections back or using a smoother scarf fabric to reduce static and snagging.

The immediate, real-world next step: the next time you style curls, record a quick 10-second video in daylight. Watch what happens when you turn your head — it’s one of the best ways to spot where definition breaks down and where shape needs adjusting.

Camera-ready red: what this project hints about colour, shine and dimension

While Kim’s project is primarily about building and animating hair for a digital MetaHuman, the fact it spotlights red is worth noting. In UK salons, red shades are often described as high-impact but higher-maintenance visually: they show variation (and dryness) quickly, and can look different in warm indoor lighting versus cool daylight.

The “digital” lesson is that red reads best when it has dimension — a believable mix of lighter and deeper areas — and when the surface looks healthy enough to reflect light evenly. Translating that to real hair:

• Dimension isn’t just highlights: It can be created through glossing/toning services, thoughtful shade placement, or simply enhancing natural variation with styling that encourages clumping and shine.
• Shine is a structure story: In general, hair that feels rough or porous can scatter light, making colour look less vibrant on camera.
• Heat and red can be a tricky pairing: Excessive heat styling can make hair feel drier; many professionals recommend using a heat protectant and keeping temperatures sensible, particularly if hair is colour-treated.

As ever, if you’re considering a significant colour change (especially to copper tones), a consultation and strand test with a trusted colourist is the most sensible route — it helps set realistic expectations for upkeep and how the shade will sit against your natural base.

Key Takeaways

• Curly red hair is a realism challenge because both curl structure and light reflection have to look “right” at once.
• Digital “hair cards” mirror real styling: believable curls come from intentional grouping, controlled variation and a strong overall silhouette.
• Animation highlights the importance of movement—styles should hold their shape when you turn your head, walk outside, or add layers like scarves.
• For camera-ready red tones, dimension and even shine matter as much as the shade itself.
• A practical next step: film your curls in daylight while moving to spot where definition, frizz or shape needs refining.

Frequently Asked Questions

What are “hair cards” in Unreal Engine character hair?
Hair cards are flat strips with hair textures applied, arranged in layers to create the look of full hair. They’re commonly used for real-time characters because they can look realistic without being as heavy as strand-by-strand simulation.

Why do curls look less defined on camera than in the mirror?
Cameras can flatten depth and emphasise frizz, especially under strong overhead lighting. Definition often improves with consistent curl clumping, adequate hold, and letting hair dry fully before disturbing the curl pattern.

What makes curly hair look “real” whether it’s digital or natural?
Believability tends to come from variation (not identical curls everywhere), a coherent overall pattern, and a silhouette that makes sense for the density and length. Too much uniformity can look artificial.

Do red and copper tones need different styling to look vibrant?
Not different, but often more intentional. Many stylists find warm tones look their best when hair has even shine and controlled texture, because roughness can dull how colour reflects light.

How can I make curls last through a typical UK winter day?
Focus on a strong set (styling in sections), a product with some hold, and reducing friction from scarves and collars. A quick refresh spray and gentle scrunch can help later, but over-touching can increase frizz.

Is it better to brush curly hair before or after styling?
For many curl routines, detangling is done when hair is wet and conditioned to reduce breakage, then curls are styled and left to set. Dry brushing can disrupt curl clumps and add frizz for some hair types.