Chapter 4: Aging, Scars, Asymmetry & Identity

Created by Sarah Choi (prompt writer using ChatGPT)

Aging, Scars, Asymmetry & Identity

For character concept artists across concepting and production. Focus: craniofacial structure, features, and emotions.

1) Why These Factors Matter

Aging, scars, and asymmetry are the biography of the face—they encode time, health, culture, labor, trauma, and temperament. Designing them well adds credibility and empathy, while giving downstream teams clear, actionable data for modeling, rigging, and materials. Treat each attribute as a parameter set with ranges that can be tuned for narrative tone (warmth, menace, grit) and gameplay readability.

2) Craniofacial Aging: Structure Before Surface

Aging is not just surface wrinkling—it is a stack of changes from bone → fat pads → muscles/ligaments → skin.

2.1 Skeletal Shifts

  • Orbital rim widens and descends slightly; the infraorbital margin becomes more prominent.
  • Maxilla resorbs subtly → dental support reduces; the nasolabial angle can rotate; the alar base widens.
  • Mandible remodels: chin (pogonion) may recede, gonial angle can open; dental loss collapses lower third.
  • Nasal cartilage thickens while septal support weakens → tip droop, longer nasal silhouette.

2.2 Fat Pads & Soft Tissue

  • Midface descent: malar fat slides off the zygoma, deepening the tear trough and nasolabial fold.
  • Temporal hollowing reveals the lateral forehead plane.
  • Perioral changes: thinning vermilion, deepening mentolabial fold, and a more pronounced orbicularis oris ring.
  • Neck: platysma banding, submental fullness or laxity.

2.3 Skin & Texture

  • Elasticity decreases: longer wrinkle retention (dynamic → static folds).
  • Texture: pores enlarge; keratin variations; solar lentigines (sun spots), telangiectasia (spider veins) in some types.
  • Material: less uniform roughness; T‑zone remains oilier; cheeks become drier/matte.

Production note: Plan for wrinkle maps over blendshapes for mid/late life stages; document the regions and compression vectors.

3) Age Ranges as Design Systems

Design life stages as libraries so you can age a character consistently across media.

  • Infant/Toddler: large cranium, tiny face; low nasal bridge; full infraorbital pads; short chin distance; smooth planes; high sclera exposure in joy. Minimal crease logic.
  • Child (6–12): orbits still large relative to face; dental transitions; soft zygoma; simple nasolabial hint.
  • Adolescent: growth spurts; brow and jaw begin definition; acne/texture cues optional; experimental grooming.
  • Young Adult: peak collagen; crisp plane transitions; minimal static wrinkles; expression amplitude higher.
  • Midlife (35–55): visible nasolabial/nasolabial fan; crow’s‑feet persistent; alar base widens; brow tails descend; hairline shifts.
  • Older Adult (55+): deeper folds, temporal hollowing, ptosis of lids, tip droop of nose, ear lobes lengthen; micro asymmetries accumulate.

Create age morph sheets: same head at 0/25/45/70 with annotated bony and soft‑tissue notes, shader deltas, and hair/groom shifts.

4) Scars: Anatomy, Story, and Shading

Scars encode events. Design them with medical plausibility and narrative intention.

4.1 Types & Reads

  • Laceration/trauma scars: irregular path, tissue bridges; align roughly with injury vector; can be depressed (atrophic) or raised (hypertrophic).
  • Surgical scars: clean arcs or straight lines; often aligned with Langer’s lines (skin tension lines) → thinner, flatter long‑term.
  • Keloids: exuberant, raised beyond wound margins; common on ear lobes, jawline, sternum; glossy surface.
  • Burns: broad texture fields; contractures can distort features; pigment variegation; shiny, thin epidermis.
  • Puncture/track scars: small, clustered—piercings, shrapnel, acne ice‑pick.

4.2 Placement & Function

  • Across brow/forehead: can interrupt frontalis movement → reduced brow amplitude.
  • Crossing lid margins: may affect blink closure and tear meniscus—use cautiously; call out rig limits.
  • Cheek → lip: can tether corner (cheilion) altering smile path—great for unique expression silhouettes.
  • Ear & jawline: keloids on lobe or postauricular fold; parotid surgery lines hide in creases.

4.3 Material & Topology

  • Roughness/Specular: scars often have a different sheen (glossier or waxy). Use a separate material ID.
  • Height/Normals: minor elevation/depression; avoid saw‑tooth edges. For burns, use broad normal noise with subtle AO pockets.
  • Hair interaction: scar tissue is glabrous—no pores/hair; plan beard/hair break lines.

Production note: Provide a scar deformation note: does it resist stretch (acts like a strap) or glide? Flag any corrective shapes needed in smiles, frowns, blinks.

5) Asymmetry: The Face’s Natural Signature

Perfect symmetry is rare and often uncanny. Controlled asymmetry adds identity and life.

5.1 Sources

  • Developmental: slightly different orbital heights, jaw length, or zygoma prominence.
  • Functional: chewing side dominance → masseter hypertrophy; habitual expressions → one brow higher.
  • Dental/occlusion: crossbite/overbite → lip posture and smile skew; tooth loss changes corner travel.
  • Trauma/medical: fractures, nerve damage (e.g., subtle Bell’s palsy), prosthetics.

5.2 Design & Readability

  • Introduce tiered asymmetry:
    • Tier 1 (silhouette): jawline drop, nose tilt, ear height.
    • Tier 2 (plane): one zygoma sharper, uneven infraorbital hollow.
    • Tier 3 (micro): brow hair direction, lip notch offset, mole placement.
  • Keep functional coherence: if one corner rides higher in smiles, maintain that across expressions and visemes.

5.3 Ethics & Respect

Design asymmetry as human richness, not mockery. Document intent (“left‑dominant smirk from violinist’s chin rest habit”) to prevent later exaggeration drifting into stereotype.

6) Identity Signals Beyond Anatomy

Faces also carry cultural and personal cues that affect recognition and appeal.

  • Grooming: hairlines, facial hair shapes, brow styling; gray distribution; dyed vs natural.
  • Ornaments & devices: piercings, tattoos, hearing aids, glasses, AR visors, respirators; design how they nest on planes and affect shadows.
  • Occupational marks: sun/frost weathering, soot staining patterns, weld spatter micro‑scars, callus at ear from comms.
  • Health cues: sleep deprivation shadows, vitamin deficiency pallor, hydration shine, smoker’s lines; use value/roughness changes over hue caricatures.

Align these with worldbuilding (faction materials, tech level) and document removability (what’s baked into model vs gear).

7) Emotions Across Age & Injury

Expression capacity changes with age and scarring.

  • Older faces: amplitude decreases at brows, increases in lower‑lid compression; smile lines persist at rest; micro‑timing (asymmetric onset) adds believability.
  • Scar‑altered faces: lip corner tethering produces unique smile arcs; lid scar may reduce blink—design compensatory cues (head tilt, brow use) for emotion clarity.
  • Chronic pain/grief reads: habitual muscle tone alters neutral—tight orbicularis, furrowed glabella, pressed lips—encode baseline temperament.

Include resting neutral variants (morning vs weary) if narrative requires.

8) Style Strategies: Realistic ↔ Stylized

  • Realistic: respect Langer’s lines when placing wrinkles; vary roughness by zone; subtle color modulation (capillary flush around nose/cheeks, cyanotic lip edges in cold).
  • Semi‑real: compress wrinkle fields into designed flow lines (crow’s‑feet fan, nasolabial S‑curve). Keep pore noise low; let planes and roughness carry age.
  • Stylized/Graphic: suggest age with shape language (drooping brow tails, squared jaw softening, nose tip droop) and 2–3 strategic fold lines. Scars reduce to a clean contour break + value shift.

Across styles, keep mouth corner architecture and lid thickness believable.

9) Production Handoff: What Teams Need

  • Orthos & Turnarounds: show before/after (youth → aged; pre‑injury → post‑injury) with plane and material notes.
  • Topology maps: orbit and lip loops; added loops along wrinkle vectors; geometry separation at alar crease and scar borders if needed.
  • Blendshape plan: AU coverage + age/scar correctives (e.g., smile with corner tether). Provide min/med/max amplitude.
  • Wrinkle maps: regions, directions, and triggers (e.g., AU6, AU4, AU9/10). Provide tiling guidance and mask falloffs.
  • Material IDs: base skin, scar tissue, wet line, vascular tint layer, makeup/soot/grease pass.
  • LOD strategy: preserve silhouette cues (nose, jaw, ear) at low LOD; collapse micro wrinkling to textures.
  • Groom notes: gray percentage by zone; beard density gaps at scars; eyebrow sparseness patterns.

10) Common Pitfalls & Fixes

  • “Wrinkle wallpaper”: adding lines everywhere. Fix: place wrinkles along compression vectors and terminate them naturally.
  • Even bilateral aging: mirror wrinkles kill credibility. Fix: offset counts/lengths; add side‑sleeping effects (one nasolabial deeper).
  • Shiny plastic scars: tune roughness; add micro‑AO along edges; reduce saturation.
  • Unanchored devices: earrings or respirators that ignore ear/nasal planes. Fix: show pressure marks, shadow occlusion, and attachment logic.
  • Age without structure: surface lines over youthful bone/fat reads fake. Fix: adjust bony landmarks and fat pads first.

11) Drills & Studies

  • Daily (15–25 min): one age morph of the same head (25 → 55) focusing on zygoma descent and nasolabial depth; one scar placement thumbnail set aligned to Langer’s lines.
  • Weekly: a 3‑pose expression mini‑sheet for an older character (neutral/joy/sad) proving amplitude and wrinkle triggers; one asymmetry portrait emphasizing jaw tilt and brow offset.
  • Monthly: a life‑arc pack (youth, midlife, elder) of a single character with consistent identity markers (scar evolves, hair grays, device upgrades). Include orthos, material passes, and blendshape notes.

12) Checklists

Structure: orbital widen/descend • maxilla resorption accounted • nasal tip droop planned • mandible angle adjusted.

Surface: midface descent • nasolabial/mentolabial defined • crow’s‑feet fan designed • neck banding mapped.

Scars: type chosen • path plausible • material ID separate • deformation notes added • hair/groom breaks marked.

Asymmetry: tiered (silhouette/plane/micro) • functional coherence maintained • ethical intent documented.

Production: orthos + before/after • topology/loops noted • blendshape & wrinkle map plan • LOD & shader notes • grooming ranges.

13) Closing

Faces age, heal, and adapt—each change is a story vector. By grounding aging, scars, and asymmetry in craniofacial mechanics and by documenting how they affect emotion and motion, you give your characters durable identity from sketch to shipped frame. Design the structure first, place the flows second, tune materials third—and let the biography of the face do the rest.