2nd/10_Wiki/Topics/Game_Design/Biomechanics-of-Injury.md

id, title, category, status, canonical_id, aliases, duplicate_of, source_trust_level, confidence_score, verification_status, tags, raw_sources, last_reinforced, github_commit, tech_stack

id	title	category	status	canonical_id	aliases	duplicate_of	source_trust_level	confidence_score	verification_status	tags	raw_sources	last_reinforced	github_commit	tech_stack
wiki-2026-0508-biomechanics-of-injury	Biomechanics of Injury	10_Wiki/Topics	verified	self	Damage Modeling Injury Simulation Hit Reaction	none	A	0.85	applied	game-design simulation damage-model biomechanics		2026-05-10	pending	language framework cpp physics-sim / game-engine

Biomechanics of Injury

매 한 줄

"매 force × tissue tolerance = injury". Biomechanics of injury 는 매 real-world impact physics (kinetic energy, pressure, strain rate) 를 매 game-grade damage model 로 mapping. 매 1990s ragdoll → 매 2010s GTA / Red Dead 2 의 procedural reaction → 매 2026 The Finales / Escape From Tarkov 의 limb-zone armor + bleed-out simulation 까지 매 evolution.

매 핵심

매 physics 기본

• Kinetic energy: KE = ½mv². 매 9mm pistol ≈ 500 J, 매 rifle round ≈ 2000-3500 J.
• Pressure: P = F/A. 매 small projectile = 매 high-pressure 침투.
• Strain rate: 매 fast load = 매 brittle fracture (bone), 매 slow = 매 bend.
• Tissue tolerance: 매 bone ≈ 130 MPa; 매 soft tissue 의 elastic limit 의 훨씬 낮음.

매 game model layers

1. Hitbox layer — body part zone (head / torso / limb).
2. Damage type — penetration / blunt / explosive / fire.
3. Armor interaction — material × thickness × angle.
4. Wound state — bleed / fracture / shock / unconscious.
5. Locomotion impact — limp / aim sway / stamina drain.

매 응용

1. Tactical shooter limb damage (Tarkov, Ready or Not, Squad).
2. Melee combat reaction (Mordhau, Chivalry 2, Kingdom Come Deliverance).
3. Vehicle crash sim (BeamNG.drive — 매 jbeam node-spring deformation).
4. Sports / action game ragdoll tuning (NBA 2K, Wrestling games).

💻 패턴

Limb-zone hit registration

struct HitResult {
    BodyPart part;       // HEAD, NECK, CHEST, ARM, LEG
    float damage;
    DamageType dtype;
    Vector3 impactPoint;
    float kineticEnergy;
};

HitResult ResolveHit(const Projectile& p, const Character& c) {
    BodyPart part = c.HitboxAt(p.lastPos);
    float ke = 0.5f * p.mass * p.velocity.SquaredLength();
    float armor = c.ArmorOn(part).StoppingPower(p.dtype);
    float damage = std::max(0.f, ke - armor) * BodyMultiplier(part);
    return {part, damage, p.dtype, p.lastPos, ke};
}

Damage multiplier table

float BodyMultiplier(BodyPart p) {
    switch (p) {
        case HEAD:  return 4.0f;
        case NECK:  return 3.0f;
        case CHEST: return 1.0f;
        case STOMACH: return 1.2f;
        case ARM:   return 0.5f;
        case LEG:   return 0.6f;
    }
}

Bleed-out simulation

class WoundState:
    def __init__(self):
        self.bleed_rate = 0.0   # HP/sec
        self.fractures = set()
        self.hp = 100.0

    def apply_hit(self, hit):
        self.hp -= hit.damage
        if hit.dtype == "PENETRATION" and hit.part in ("CHEST", "STOMACH"):
            self.bleed_rate += 0.5
        if hit.dtype == "BLUNT" and hit.kinetic_energy > 1500:
            self.fractures.add(hit.part)

    def tick(self, dt):
        self.hp -= self.bleed_rate * dt

Locomotion impact (limp from leg fracture)

float MoveSpeedMultiplier(const WoundState& w) {
    float m = 1.0f;
    if (w.fractures.contains(LEG_LEFT))  m *= 0.55f;
    if (w.fractures.contains(LEG_RIGHT)) m *= 0.55f;
    if (w.bleedRate > 1.0f)              m *= 0.85f; // hypovolemic
    return m;
}

Ragdoll impulse from impact

void ApplyImpactRagdoll(Rigidbody bone, Vector3 dir, float ke) {
    float impulse = Mathf.Sqrt(2 * ke * bone.mass);
    bone.AddForceAtPosition(dir * impulse, hitPoint, ForceMode.Impulse);
}

Armor angle attenuation

def effective_armor(armor_thickness_mm, hit_angle_deg):
    """Slope-thickness: thicker at oblique angle."""
    import math
    return armor_thickness_mm / math.cos(math.radians(min(hit_angle_deg, 80)))

매 결정 기준

상황	Approach
Arcade shooter (CoD, Apex)	1-tap headshot, 매 simple multiplier
Mil-sim (Tarkov, Squad)	매 full limb + armor + bleed
RPG (Cyberpunk, Fallout)	매 limb cripple + status effect
Vehicle sim (BeamNG)	매 node-spring deformation (no hitbox)
Melee (Chivalry, Mordhau)	매 directional hit + body part + stamina

기본값: Hitbox + multiplier + simple bleed → 매 expand 의 incremental.

🔗 Graph

• 부모: Game_Physics
• 응용: Combat_Balance_Buff
• Adjacent: Procedural-Level-Geometry

🤖 LLM 활용

언제: 매 tactical / sim 게임 의 damage model design, 매 hit-feel iteration, 매 armor balance. 언제 X: 매 abstract / arcade game (매 단순 HP bar 가 더 적합).

❌ 안티패턴

• Realism > fun: 매 realistic 1-shot kill 이 매 PVP 의 frustration source.
• Limb zone 의 inflation: 매 너무 많은 zone (12+) = 매 hitreg 의 confusion.
• No feedback: 매 hit 의 visual / audio cue 의 X = 매 player 의 "did I hit?" 의 ambiguity.

🧪 검증 / 중복

• Verified (NIJ ballistic standards 2008; BeamNG dev blog 2023; Tarkov hit zone GDC 2024 talk).
• 신뢰도 A-.

🕓 Changelog

날짜	변경
2026-05-08	Phase 1
2026-05-10	Manual cleanup — KE / armor / bleed model, limb multiplier, ragdoll impulse