2nd/10_Wiki/Topics/Architecture/Modular-Weapon-Evolution-and-Skill-Trees.md

---
id: wiki-2026-0508-modular-weapon-evolution-and-ski
title: Modular Weapon Evolution and Skill Trees
category: 10_Wiki/Topics
status: verified
canonical_id: self
aliases: [Weapon Mods, Skill Tree Design, Build Diversity]
duplicate_of: none
source_trust_level: A
confidence_score: 0.85
verification_status: applied
tags: [game-design, progression, weapons, skill-trees]
raw_sources: []
last_reinforced: 2026-05-10
github_commit: pending
tech_stack:
  language: csharp
  framework: unity-godot
---

# Modular Weapon Evolution and Skill Trees

## 매 한 줄
> **"매 weapon = base + slots; 매 build = path through tree"**. Borderlands / Path of Exile / Diablo IV 의 ARPG progression DNA. 2026 modern: data-driven mod system + procedural affix + branching tree 의 build diversity 의 driver.

## 매 핵심

### 매 component
- **Base weapon**: archetype (sword, bow, SMG) + base stats.
- **Mod slot**: socket (scope, mag, barrel) — typed, capacity-limited.
- **Affix**: procedural roll (+15% crit, leech, elemental).
- **Skill node**: tree position — passive bonus or active skill.

### 매 design axis
- **Power**: mod 의 raw stat boost.
- **Identity**: mod 의 playstyle change (full-auto → burst).
- **Trade-off**: pro/con — high damage / low fire rate.
- **Synergy**: 매 mod combo 의 emergent build.

### 매 응용
1. Looter shooter: random affix + slot mod.
2. ARPG: deep tree (200+ nodes) + gem socket.
3. Roguelike: per-run modular evolution.

## 💻 패턴

### Weapon ScriptableObject (Unity)
```csharp
[CreateAssetMenu(menuName = "Weapons/Base")]
public class WeaponBase : ScriptableObject
{
    public string id;
    public WeaponArchetype archetype;
    public float baseDamage;
    public float baseFireRate;
    public List<ModSlot> slots; // Scope, Magazine, Barrel
}

public enum ModSlot { Scope, Magazine, Barrel, Stock, Underbarrel }
```

### Mod definition
```csharp
[CreateAssetMenu(menuName = "Weapons/Mod")]
public class WeaponMod : ScriptableObject
{
    public string id;
    public ModSlot slot;
    public List<StatModifier> modifiers;
    public List<TagAdd> tagsAdded; // "burst-fire", "ignite"
}

[Serializable]
public struct StatModifier
{
    public StatType stat;        // Damage, FireRate, Recoil
    public OpType op;            // Add, Mul, Override
    public float value;
}
```

### Composed weapon instance
```csharp
public class WeaponInstance
{
    public WeaponBase Base { get; }
    public Dictionary<ModSlot, WeaponMod> Mods { get; } = new();
    public List<Affix> Affixes { get; } = new(); // procedural rolls

    public float Damage => ComputeStat(StatType.Damage);

    float ComputeStat(StatType s)
    {
        float v = Base.GetBase(s);
        var add = Mods.Values.SelectMany(m => m.modifiers)
            .Concat(Affixes.SelectMany(a => a.modifiers))
            .Where(m => m.stat == s);
        foreach (var m in add.Where(m => m.op == OpType.Add)) v += m.value;
        foreach (var m in add.Where(m => m.op == OpType.Mul)) v *= 1 + m.value;
        return v;
    }
}
```

### Procedural affix roll
```csharp
public static Affix RollAffix(int itemLevel, AffixPool pool)
{
    var weighted = pool.entries.Where(e => e.minLevel <= itemLevel);
    var pick = WeightedPick(weighted, e => e.weight);
    float val = Mathf.Lerp(pick.minRoll, pick.maxRoll, Random.value);
    return new Affix { stat = pick.stat, op = pick.op, value = val };
}
```

### Skill node graph
```csharp
public class SkillNode
{
    public string id;
    public Vector2 position;
    public List<string> prerequisites;
    public List<StatModifier> passiveBonus;
    public ActiveSkill activeSkill; // null for passive nodes
    public int cost = 1;
}

public class SkillTree
{
    public Dictionary<string, SkillNode> nodes;
    public HashSet<string> allocated = new();

    public bool Allocate(string id, ref int points)
    {
        var n = nodes[id];
        if (points < n.cost) return false;
        if (!n.prerequisites.All(allocated.Contains)) return false;
        allocated.Add(id);
        points -= n.cost;
        return true;
    }
}
```

### Synergy detection
```csharp
public static List<string> DetectSynergies(WeaponInstance w, SkillTree t)
{
    var tags = w.AllTags().Concat(t.AllocatedTags()).ToHashSet();
    return SynergyDb.All
        .Where(s => s.requiredTags.All(tags.Contains))
        .Select(s => s.name)
        .ToList();
}
```

### Respec system
```csharp
public void Respec(SkillTree t, ref int points)
{
    points += t.allocated.Sum(id => t.nodes[id].cost);
    t.allocated.Clear();
}
```

### Build serialization (share builds)
```csharp
public string Encode(SkillTree t) =>
    Convert.ToBase64String(Encoding.UTF8.GetBytes(string.Join(",", t.allocated)));
```

## 매 결정 기준
| 상황 | Approach |
|---|---|
| Casual shooter | 3-5 slot mods, no affixes |
| Looter | Slots + procedural affixes (3-6) |
| Deep ARPG | Slots + affixes + 100+ skill tree |
| Roguelike | Drafted upgrades, run-scoped |

**기본값**: ScriptableObject base + slot mods + 3-tier affix + 50-node tree.

## 🔗 Graph
- 응용: [[Build-Diversity]]
- Adjacent: [[ECS]]

## 🤖 LLM 활용
**언제**: 매 affix table 의 generate, synergy combo 의 enumerate, balance simulation script.
**언제 X**: 매 power-fantasy feel, animation game-feel — designer/playtest judgment.

## ❌ 안티패턴
- **Power creep**: 매 new mod 의 strict upgrade. Old mods 의 dead.
- **Illusion of choice**: 100 tree nodes, 1 optimal path. Build diversity = 0.
- **Reroll fatigue**: 매 affix 의 100 reroll 의 required = grind, not gameplay.
- **No respec**: 매 mistake = restart character. 매 modern player 의 quit.

## 🧪 검증 / 중복
- Verified (Path of Exile dev manifestos, Borderlands 3 GDC talks, Last Epoch design notes 2025).
- 신뢰도 B+ (game-design subjective, but established patterns).

## 🕓 Changelog
| 날짜 | 변경 |
|---|---|
| 2026-05-08 | Phase 1 |
| 2026-05-10 | Manual cleanup — modular weapon + skill tree systems with Unity patterns |