# 3d Games

> 3D game development principles. Rendering, shaders, physics, cameras.

- Skill: `yunaamelia/3d-games` (Agent Skill)
- Install (CLI): `npx skillmds add yunaamelia/3d-games`
- Raw SKILL.md: https://api.skillmd.com/api/skills/yunaamelia/3d-games/raw
- Safety review: pending
- Works with: Claude Code, Claude.ai, OpenAI Codex
- Category: AI & ML
- Author: yunaamelia (https://skillmd.com/u/yunaamelia)
- Updated: 2026-09-10
- Page: https://skillmd.com/skills/yunaamelia/3d-games

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# 3D Game Development

> Principles for 3D game systems.

---

## 1. Rendering Pipeline

### Stages

```
1. Vertex Processing → Transform geometry
2. Rasterization → Convert to pixels
3. Fragment Processing → Color pixels
4. Output → To screen
```

### Optimization Principles

| Technique             | Purpose                 |
| --------------------- | ----------------------- |
| **Frustum culling**   | Don't render off-screen |
| **Occlusion culling** | Don't render hidden     |
| **LOD**               | Less detail at distance |
| **Batching**          | Combine draw calls      |

---

## 2. Shader Principles

### Shader Types

| Type               | Purpose             |
| ------------------ | ------------------- |
| **Vertex**         | Position, normals   |
| **Fragment/Pixel** | Color, lighting     |
| **Compute**        | General computation |

### When to Write Custom Shaders

- Special effects (water, fire, portals)
- Stylized rendering (toon, sketch)
- Performance optimization
- Unique visual identity

---

## 3. 3D Physics

### Collision Shapes

| Shape       | Use Case            |
| ----------- | ------------------- |
| **Box**     | Buildings, crates   |
| **Sphere**  | Balls, quick checks |
| **Capsule** | Characters          |
| **Mesh**    | Terrain (expensive) |

### Principles

- Simple colliders, complex visuals
- Layer-based filtering
- Raycasting for line-of-sight

---

## 4. Camera Systems

### Camera Types

| Type             | Use                 |
| ---------------- | ------------------- |
| **Third-person** | Action, adventure   |
| **First-person** | Immersive, FPS      |
| **Isometric**    | Strategy, RPG       |
| **Orbital**      | Inspection, editors |

### Camera Feel

- Smooth following (lerp)
- Collision avoidance
- Look-ahead for movement
- FOV changes for speed

---

## 5. Lighting

### Light Types

| Type            | Use               |
| --------------- | ----------------- |
| **Directional** | Sun, moon         |
| **Point**       | Lamps, torches    |
| **Spot**        | Flashlight, stage |
| **Ambient**     | Base illumination |

### Performance Consideration

- Real-time shadows are expensive
- Bake when possible
- Shadow cascades for large worlds

---

## 6. Level of Detail (LOD)

### LOD Strategy

| Distance | Model            |
| -------- | ---------------- |
| Near     | Full detail      |
| Medium   | 50% triangles    |
| Far      | 25% or billboard |

---

## 7. Anti-Patterns

| ❌ Don't                    | ✅ Do                 |
| --------------------------- | --------------------- |
| Mesh colliders everywhere   | Simple shapes         |
| Real-time shadows on mobile | Baked or blob shadows |
| One LOD for all distances   | Distance-based LOD    |
| Unoptimized shaders         | Profile and simplify  |

---

> **Remember:** 3D is about illusion. Create the impression of detail, not the detail itself.