# Asset License Policy

All assets in this repository must have clear licensing and provenance.

## Allowed License Types

### Tier 1: Unrestricted (Preferred)

| License | Requirements | Folder |
|---------|--------------|--------|
| **CC0 / Public Domain** | None | `Content/Ralpha/Assets/` |
| **Unlicense** | None | `Content/Ralpha/Assets/` |
| **MIT** | Include license file | `Content/Ralpha/Assets/` |

### Tier 2: Attribution Required

| License | Requirements | Folder |
|---------|--------------|--------|
| **CC-BY** | Credit in catalogue.json | `Content/Ralpha/Assets/` |
| **CC-BY-SA** | Credit + share-alike | `Content/Ralpha/Assets/` |

### Tier 3: Platform-Specific

| License | Requirements | Folder |
|---------|--------------|--------|
| **Quixel Megascans** | Free with UE, UE projects only | `Content/Ralpha/Assets/` |
| **UE Marketplace** | Purchased, UE projects only | `Content/Ralpha/Assets/` |
| **Sketchfab Store** | Purchased, per-asset license | `Content/Ralpha/Assets/` |

### Tier 4: Restricted

| License | Requirements | Folder |
|---------|--------------|--------|
| **NC (Non-Commercial)** | Non-commercial use only | `Content/Ralpha/Restricted/` |
| **Custom/Unknown** | Case-by-case review | `Content/Ralpha/Restricted/` |

## Prohibited

- **ND (No Derivatives)** - Cannot modify, doesn't work for our use case
- **Copyrighted without license** - No unlicensed assets
- **AI-generated without rights** - Must have clear generation rights

## Catalogue Requirements

Every asset in `catalogue.json` must include:

```json
{
  "license": {
    "type": "CC0",           // Required: license identifier
    "source": "Poly Haven",   // Required: where asset came from
    "attribution": null,      // Required for CC-BY: credit text
    "url": "https://..."      // Optional: source URL
  }
}
```

## Recommended Sources

### Free / CC0

| Source | License | Quality | Notes |
|--------|---------|---------|-------|
| [Poly Haven](https://polyhaven.com) | CC0 | Excellent | HDRIs, textures, models |
| [Sketchfab CC0](https://sketchfab.com/search?features=downloadable&licenses=cc0) | CC0 | Variable | Filter by license |
| [cgbookcase](https://cgbookcase.com) | CC0 | Good | Textures |
| [ambientCG](https://ambientcg.com) | CC0 | Good | PBR textures |
| [Kenney](https://kenney.nl) | CC0 | Stylized | Low-poly assets |

### With UE License

| Source | License | Quality | Notes |
|--------|---------|---------|-------|
| [Quixel Megascans](https://quixel.com/megascans) | Megascans | Excellent | Free with UE |
| [UE Marketplace](https://unrealengine.com/marketplace) | Marketplace | Variable | Many free monthly |

### Paid

| Source | License | Quality | Notes |
|--------|---------|---------|-------|
| [TurboSquid](https://turbosquid.com) | Per-asset | Variable | Check each license |
| [CGTrader](https://cgtrader.com) | Per-asset | Variable | Check each license |
| [Sketchfab Store](https://sketchfab.com/store) | Per-asset | Variable | Royalty-free options |

## Adding New Assets

1. **Verify license** before importing
2. **Document source** in commit message
3. **Add to catalogue** with full license info
4. **Place in correct folder** based on license tier

## Audit Process

Periodically run:

```bash
# Find assets missing license info
python RalphaData/scripts/audit_licenses.py
```

## Questions?

If unsure about an asset's license:
1. Don't add it
2. Ask in PR/issue
3. Find alternative with clear license

---

*Last Updated: 2026-01-20*