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UV Workflow
Efficient UV layouts with consistent texel density. Seams at hidden edges. Engine-ready.
When to Use
- After topology locked, before texturing
- Modular kit UV atlas planning
- Lightmap UV channel setup
- UDIM workflows for hero assets
Workflow
UV Planning → Seam Marking → Unwrap → Texel Density Check
→ Pack → Mirror/Overlap Decision → Lightmap UV (if needed) → ValidationSeam Placement Rules
Place seams at:
- Back of head, spine centerline
- Inner arms, inner legs
- Bottom of chin, underside of objects
- Panel edges on hard surface (construction seams)
- Hidden areas under clothing/overlaps
Never place seams on:
- Face (front)
- Primary gameplay-visible surfaces
- Deforming joint centers (relocate to nearby hidden area)
Texel Density
Formula: Texel Density = Texture Resolution / UV Island Size in UV space
Target consistency across visible surfaces:
| Asset Tier | Target TD (px/m) |
|---|---|
| Hero | 512–1024 px/m |
| Standard | 256–512 px/m |
| Background | 128–256 px/m |
Use same density for modular kit pieces sharing atlas.
Unwrap Methods
| Method | Use When |
|---|---|
| Smart UV Project | Quick blockout UVs only |
| Follow Active Quads | Strip UVs (roads, limbs) |
| Cube Project | Boxy hard surface |
| Lightmap Pack | Lightmap channel |
| Manual seam + Unwrap | Production default |
UV Packing
- Margin: 0.002–0.01 UV units (engine dependent)
- Rotate islands for maximum packing efficiency
- Group islands by material ID
- Keep related islands near each other in UV space
- Use UVPackmaster or native pack for production
Mirrored UVs
- Mirror UVs for symmetrical characters (save texture space)
- Offset mirrored islands slightly if engine requires unique bakes
- Mark mirrored halves in object naming:
_L/_Rmeshes if separate
UDIM Workflow
For hero assets exceeding single 4K texture:
- Tile 1001: head
- Tile 1002: torso
- Tile 1003: limbs
- Document tile assignment in production brief
Lightmap UVs
Second UV channel requirements:
- No overlapping islands
- Consistent texel density less critical
- Larger margin (0.02+) for light bleed prevention
- Pack separately from texture UVs
Modular UV Atlas
1. Plan shared atlas resolution (2048/4096)
2. Assign UV islands per module to atlas regions
3. Trim sheet regions for repeating detail
4. Vertex color variation for module differentiation
5. Document atlas layout for texture artistMCP Integration
- Mark seams via MCP if supported
- Execute unwrap via MCP
- Query UV island count and pack efficiency
- Assign UV channels via MCP
- Validate no overlapping UVs (except intentional mirror)
Validation Checklist
- [ ] No unintended overlapping UVs
- [ ] Consistent texel density on visible surfaces
- [ ] Seams hidden at gameplay angles
- [ ] UV islands within 0–1 (or UDIM tiles assigned)
- [ ] Lightmap channel separate if required
- [ ] Pack efficiency > 75%
Constraints
MUST DO
- Plan UVs before final modeling (topology informed by UV needs)
- Maintain texel density consistency
- Hide seams at logical construction edges
- Create lightmap UVs for baked lighting pipelines
- Document atlas layout for modular kits
MUST NOT DO
- Smart UV Project as final production UVs
- Overlapping UVs on unique surface detail (unless mirrored)
- Inconsistent texel density on same asset tier
- Seams across faces or primary visible surfaces
- Skip packing margins
Reference Guide
| Topic | Reference | Load When |
|---|---|---|
| Texel density calc | references/texel-density.md | Hero assets |
| Trim sheets | references/trim-sheets.md | Modular kits |

