2nd/10_Wiki/Topics/AI_and_ML/Splash Damage.md

---
id: wiki-2026-0508-splash-damage
title: Splash Damage
category: 10_Wiki/Topics
status: verified
canonical_id: self
aliases: [aoe-damage, area-of-effect, blast-radius]
duplicate_of: none
source_trust_level: A
confidence_score: 0.9
verification_status: applied
tags: [game-design, combat, balance, aoe]
raw_sources: []
last_reinforced: 2026-05-10
github_commit: pending
tech_stack:
  language: csharp
  framework: unity
---

# Splash Damage

## 매 한 줄
> **"매 single hit, multiple targets — 매 spatial damage distribution"**. Splash damage (AoE damage) 는 매 impact point 주변 radius 의 모든 entity 에 damage 의 분배 — 매 RTS/MOBA/shooter 의 mechanic. 매 falloff curve, friendly fire, line-of-sight 의 design knob.

## 매 핵심

### 매 정의
- **Splash damage**: 매 projectile/explosion 의 impact point 주변 area 에 damage 분배.
- **Direct damage**: 매 center hit 의 full damage.
- **Falloff**: 매 distance 증가 → damage 감소 (linear / quadratic / step).
- **Friendly fire**: 매 같은 team 도 damage 의 적용 여부.

### 매 Balance Knob
- **Radius**: 매 damage area 의 크기. 매 클수록 anti-clump 강함.
- **Falloff curve**: 매 linear (predictable) vs quadratic (focused) vs flat (binary).
- **Damage cap**: 매 단일 target 에 대한 multi-source stacking 제한.
- **Cast time / projectile speed**: 매 dodge window — 매 빠를수록 strong.
- **Cooldown / mana cost**: 매 spam 방지.

### 매 응용
1. **RTS** — 매 siege tank, mortar (StarCraft 의 anti-clump unit).
2. **MOBA** — 매 Brand, Annie ult (League of Legends 의 teamfight tool).
3. **Shooter** — 매 rocket launcher, grenade (Quake/Overwatch).
4. **Tower Defense** — 매 splash tower 의 wave 처리.

## 💻 패턴

### Linear Falloff Splash (Unity C#)
```csharp
public class SplashDamage : MonoBehaviour {
    public float radius = 5f;
    public float maxDamage = 100f;
    public LayerMask targetMask;

    public void Explode(Vector3 center) {
        Collider[] hits = Physics.OverlapSphere(center, radius, targetMask);
        foreach (var hit in hits) {
            float dist = Vector3.Distance(center, hit.transform.position);
            float falloff = Mathf.Clamp01(1f - dist / radius);
            float dmg = maxDamage * falloff;
            hit.GetComponent<Health>()?.TakeDamage(dmg);
        }
    }
}
```

### Quadratic Falloff (focused)
```csharp
float falloff = Mathf.Clamp01(1f - Mathf.Pow(dist / radius, 2f));
```

### Line-of-Sight Check (배경 차단)
```csharp
foreach (var hit in hits) {
    Vector3 dir = (hit.transform.position - center).normalized;
    float dist = Vector3.Distance(center, hit.transform.position);
    if (Physics.Raycast(center, dir, dist, obstacleMask)) continue; // blocked by wall
    ApplyDamage(hit, ComputeDamage(dist));
}
```

### Friendly Fire Toggle
```csharp
if (!friendlyFire && hit.GetComponent<Team>().id == casterTeamId) continue;
```

### Damage Cap (multi-source)
```csharp
public class DamageCap : MonoBehaviour {
    Dictionary<int, float> frameDamage = new();
    public float capPerFrame = 200f;

    public float TryApply(float requested) {
        int frame = Time.frameCount;
        float current = frameDamage.GetValueOrDefault(frame, 0f);
        float allowed = Mathf.Min(requested, capPerFrame - current);
        frameDamage[frame] = current + allowed;
        return allowed;
    }
}
```

### Visual Feedback (impulse + VFX)
```csharp
foreach (var rb in Physics.OverlapSphere(center, radius)
    .Select(c => c.GetComponent<Rigidbody>()).Where(r => r)) {
    rb.AddExplosionForce(800f, center, radius, 1f, ForceMode.Impulse);
}
Instantiate(explosionVFX, center, Quaternion.identity);
```

## 매 결정 기준
| 상황 | Approach |
|---|---|
| Anti-clump 의도 | 큰 radius + linear falloff |
| Skillshot reward | 작은 radius + quadratic (center 의 보상) |
| Crowd control 보조 | flat damage + 큰 radius + slow effect |
| Anti-tank | small radius + high direct + low falloff |
| Friendly fire 의 hardcore | enable + visual warning |

**기본값**: linear falloff, radius 3~5m (FPS), no friendly fire (casual), damage cap 의 multi-rocket spam 방지.

## 🔗 Graph
- 부모: [[Game-Combat-Design]] · [[Damage-Models]]
- 변형: [[Direct-Damage]] · [[Damage-over-Time]] · [[Chain-Damage]]
- 응용: [[RTS-Design]] · [[MOBA-Design]] · [[Tower-Defense]] · [[FPS-Weapon-Design]]
- Adjacent: [[Hitbox-Design]] · [[Projectile-Physics]] · [[Knockback]] · [[Game-Balance]]

## 🤖 LLM 활용
**언제**: balance prototyping (LLM 에 numbers 제안 요청), tooltip writing, design doc review.
**언제 X**: live PvP balance 의 final tuning — 매 player data 가 ground truth.

## ❌ 안티패턴
- **Binary radius**: damage 가 edge 에서 급락 → 매 unsatisfying. Falloff curve 사용.
- **No visual indicator**: player 가 radius 모름. Decal / outline 표시.
- **Friendly fire on by default in casual**: rage quit. Opt-in 권장.
- **Stacking exploit**: 5 rocket 동시 발사 의 one-shot. Damage cap 적용.
- **Through-wall damage 의 무시**: realism 깨짐 except 의도된 경우 (e.g. C4).

## 🧪 검증 / 중복
- Verified (Unity Physics docs, Riot Games balance talks, GDC Vault 의 splash design lectures).
- 신뢰도 A.

## 🕓 Changelog
| 날짜 | 변경 |
|---|---|
| 2026-05-08 | Phase 1 |
| 2026-05-10 | Manual cleanup — splash damage mechanics + Unity patterns |