---
name: 3d-games
description: "3D game development principles. Rendering, shaders, physics, cameras."
allowed-tools: Read, Write, Edit, Glob, Grep
risk: unknown
source: community
---
# 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.
## When to Use
This skill is applicable to execute the workflow or actions described in the overview.