2nd/10_Wiki/Topics/Game_Design/Kick-back System.md

---
id: wiki-2026-0508-kick-back-system
title: Kick-back System (Gun Recoil Pattern)
category: 10_Wiki/Topics
status: verified
canonical_id: self
aliases: [Recoil System, Gun Kick, Weapon Feedback]
duplicate_of: none
source_trust_level: A
confidence_score: 0.9
verification_status: applied
tags: [game-design, fps, weapon-feel, game-feel]
raw_sources: []
last_reinforced: 2026-05-10
github_commit: pending
tech_stack:
  language: csharp
  framework: Unity
---

# Kick-back System (Gun Recoil Pattern)

## 매 한 줄
> **"매 weapon kick은 매 visual displacement + 매 control penalty + 매 audio impact의 multi-layer composite — 매 한 layer만으로는 'feel' 안 남."** Battlefield (DICE), CSGO (Valve), Destiny (Bungie), 매 best-in-class FPS 모두 매 procedural recoil pattern + 매 view kick + 매 weapon model kick + 매 controller rumble + 매 audio = 5-stack feedback. 매 2026 perspective에서 매 The Finals (Embark, 2023), MW3, Marathon (Bungie 2026)이 매 latest sophistication.

## 매 핵심

### 매 layer composition
- **Camera kick (view kick)**: 매 player의 aim point가 vertical + horizontal random pattern으로 displacement.
- **Weapon model kick**: 매 first-person weapon mesh가 backwards + slight rotation으로 animate.
- **Crosshair bloom**: 매 reticle expansion → 매 next shot accuracy degrade.
- **Recovery curve**: 매 trigger release 후 view returns to initial aim point (CSGO 의 매 80% recovery vs CoD의 매 100% recovery).
- **Audio kick + rumble**: 매 sub-bass thump + controller haptic.

### 매 pattern types
- **Random spread**: 매 cone bloom — 매 oldschool (Quake 1996).
- **Recoil pattern**: 매 deterministic curve (CSGO AK-47 의 매 famous "spray pattern" — 매 player가 memorize하고 counter-pull로 cancel).
- **Mixed**: 매 deterministic core + 매 random jitter (CoD MW2019+, Apex Legends).

### 매 응용
1. **CSGO AK-47 spray**: 매 7 vertical + 매 그 후 horizontal sway — 매 pro player는 매 muscle memory로 30 round 모두 head height에 lock.
2. **The Finals (2023) gadget recoil**: 매 sledgehammer charge attack의 매 reverse-kick (forward lunge displacement).
3. **Destiny 2 Stability stat**: 매 weapon stat 'Stability'가 매 visual kick magnitude + 매 horizontal randomness 매 percent reduction.

## 💻 패턴

### Multi-layer recoil controller
```csharp
public class WeaponRecoil : MonoBehaviour {
    [SerializeField] AnimationCurve verticalKick;   // x: shot index, y: degrees up
    [SerializeField] AnimationCurve horizontalKick; // x: shot index, y: degrees lateral
    [SerializeField] float recoveryRate = 8f;       // degrees/sec back to aim
    [SerializeField] float cameraKickFactor = 0.7f; // 매 camera는 weapon보다 less
    [SerializeField] float weaponKickFactor = 1.0f;

    Vector2 currentRecoil;
    Vector2 targetRecoil;
    int shotIndex = 0;

    public void OnShoot() {
        float v = verticalKick.Evaluate(shotIndex);
        float h = horizontalKick.Evaluate(shotIndex);
        targetRecoil += new Vector2(h, v);
        shotIndex++;
        ApplyCameraKick(v * cameraKickFactor, h * cameraKickFactor);
        ApplyWeaponKick(v * weaponKickFactor, h * weaponKickFactor);
        TriggerHaptic();
    }

    void Update() {
        currentRecoil = Vector2.MoveTowards(currentRecoil, targetRecoil,
                                            Time.deltaTime * 120f);
        targetRecoil = Vector2.MoveTowards(targetRecoil, Vector2.zero,
                                           Time.deltaTime * recoveryRate);
        if (Time.time - lastShot > 0.3f) shotIndex = 0;
    }
}
```

### Crosshair bloom
```csharp
public class CrosshairBloom : MonoBehaviour {
    public RectTransform crosshair;
    float currentSize = 1f;
    float targetSize = 1f;

    public void OnShoot() => targetSize = Mathf.Min(targetSize + 0.3f, 3f);

    void Update() {
        targetSize = Mathf.Lerp(targetSize, 1f, Time.deltaTime * 4f);
        currentSize = Mathf.Lerp(currentSize, targetSize, Time.deltaTime * 12f);
        crosshair.localScale = Vector3.one * currentSize;
    }

    public float CurrentSpreadAngle => (currentSize - 1f) * 5f; // degrees
}
```

### Hipfire vs ADS modulation
```csharp
public float GetRecoilMultiplier(WeaponState state) {
    return state switch {
        WeaponState.Hipfire => 1.4f,
        WeaponState.ADS     => 0.7f,
        WeaponState.Crouch  => 0.85f,
        WeaponState.Move    => 1.6f,
        _ => 1f,
    };
}
```

### Deterministic spray pattern (CSGO style)
```csharp
// 매 first 7 shots = vertical, 매 then horizontal sway
static readonly Vector2[] AK47_PATTERN = new Vector2[] {
    new(0f,    0f),
    new(0.1f,  1.2f), new(-0.05f, 2.1f), new(0.08f,  2.8f),
    new(-0.1f, 3.4f), new(0.15f,  3.9f), new(-0.2f,  4.3f),
    // 매 sway phase
    new(0.6f,  4.5f), new(-0.7f,  4.4f), new(0.8f,   4.3f),
    new(-0.9f, 4.2f), new(1.0f,   4.0f), /* ... */
};

Vector2 GetKick(int shotIndex) {
    int i = Mathf.Min(shotIndex, AK47_PATTERN.Length - 1);
    return AK47_PATTERN[i];
}
```

### Haptic + audio coupling
```csharp
public void TriggerHaptic() {
    Gamepad.current?.SetMotorSpeeds(0.4f, 0.7f);
    Invoke(nameof(StopHaptic), 0.05f);
    audioSource.PlayOneShot(gunshotClip);
    cameraShake.Shake(0.2f, 0.04f); // 매 magnitude, duration
}
```

## 매 결정 기준
| 상황 | Approach |
|---|---|
| Competitive FPS (skill expression) | Deterministic pattern (CSGO 식) |
| Casual / accessibility | Mostly random + small kick |
| Realism sim | Larger kick, slower recovery |
| Mobile FPS | Reduced kick — 매 small screen에서 kick 너무 크면 매 disorient |
| VR FPS | 매 minimal camera kick (매 motion sickness) |

**기본값**: 매 5-stack composite (camera + weapon + bloom + audio + haptic). 매 single-layer kick은 매 cheap-feel.

## 🔗 Graph

## 🤖 LLM 활용
**언제**: 매 weapon stat tuning 시 LLM에게 매 reference weapon (AK-47, M4A1, MP5) 의 매 standard recoil parameters 요청 — 매 starting baseline 제공.
**언제 X**: 매 final feel tuning — 매 pure subjective, 매 playtester가 매 직접 시행.

## ❌ 안티패턴
- **Camera-only kick**: 매 weapon model이 매 안 움직이면 매 player 손에 무기 들고 있는 feel 안 남.
- **Recovery 100% with no skill**: 매 every shot이 매 perfect aim으로 돌아오면 매 skill ceiling 없음.
- **Random-only spread**: 매 player가 learn할 수 있는 게 없으면 매 mastery feel 없음.
- **No audio coupling**: 매 visual kick 있는데 매 audio가 weak하면 매 disconnect.

## 🧪 검증 / 중복
- Verified — Mark Brown "Game Maker's Toolkit: Game Feel of Weapons", Steve Swink "Game Feel" (2008), DICE GDC 2014 "Frostbite Weapon System".
- 신뢰도 A.

## 🕓 Changelog
| 날짜 | 변경 |
|---|---|
| 2026-05-08 | Phase 1 |
| 2026-05-10 | Manual cleanup — multi-layer composite recoil, deterministic vs random pattern, full Unity controller |