# Changelog 50: Mesh Cleanup & Optimization Tools

**Date:** 2025-11-30
**Type:** Feature
**Tasks:** TASK-030-1, TASK-030-2, TASK-030-3, TASK-030-4

---

## Summary

Implemented mesh cleanup and optimization tools essential for game development workflows. These tools handle common mesh issues like excessive polycount, triangulated imports, and inverted normals.

---

## New Features

### TASK-030-1: mesh_dissolve
- **Tool:** `mesh_dissolve`
- **Functionality:** Dissolves selected geometry while preserving shape
- **Parameters:**
  - `dissolve_type`: "limited", "verts", "edges", "faces" (default: "limited")
  - `angle_limit`: Angle threshold in degrees for limited dissolve (default: 5.0)
  - `use_face_split`: Split faces during dissolve (default: false)
  - `use_boundary_tear`: Tear boundary during dissolve (default: false)
- **Use cases:** Cleanup after boolean operations, removing edge loops, import cleanup

### TASK-030-2: mesh_tris_to_quads
- **Tool:** `mesh_tris_to_quads`
- **Functionality:** Converts triangles to quads where possible
- **Parameters:**
  - `face_threshold`: Maximum angle between face normals in degrees (default: 40.0)
  - `shape_threshold`: Maximum shape deviation allowed in degrees (default: 40.0)
- **Use cases:** Cleaning triangulated imports (OBJ, FBX), post-boolean cleanup, preparing mesh for subdivision

### TASK-030-3: mesh_normals_make_consistent
- **Tool:** `mesh_normals_make_consistent`
- **Functionality:** Recalculates normals to face consistently outward or inward
- **Parameters:**
  - `inside`: If true, normals point inward (default: false)
- **Use cases:** Fixing inverted faces (black patches in render), inconsistent shading, boolean operation artifacts

### TASK-030-4: mesh_decimate
- **Tool:** `mesh_decimate`
- **Functionality:** Reduces polycount while preserving shape (Edit Mode operation)
- **Parameters:**
  - `ratio`: Target ratio of faces to keep, 0.0-1.0 (default: 0.5)
  - `use_symmetry`: Maintain mesh symmetry during decimation (default: false)
  - `symmetry_axis`: Axis for symmetry - "X", "Y", or "Z" (default: "X")
- **Use cases:** LOD generation, game-ready asset optimization, retopology preparation

---

## Implementation Details

### 4-Layer Architecture

| Layer | File | Changes |
|-------|------|---------|
| Domain | `server/domain/tools/mesh.py` | Added 4 abstract methods |
| Application | `server/application/tool_handlers/mesh_handler.py` | Added 4 RPC handler methods |
| Adapter | `server/adapters/mcp/areas/mesh.py` | Added 4 MCP tool definitions with semantic tags |
| Addon | `blender_addon/application/handlers/mesh.py` | Added 4 Blender API implementations |
| Addon | `blender_addon/__init__.py` | Registered 4 RPC handlers |

### Blender API Usage

| Tool | Blender Operations |
|------|-------------------|
| dissolve | `bpy.ops.mesh.dissolve_limited`, `dissolve_verts`, `dissolve_edges`, `dissolve_faces` |
| tris_to_quads | `bpy.ops.mesh.tris_convert_to_quads` |
| normals_make_consistent | `bpy.ops.mesh.normals_make_consistent` |
| decimate | `bpy.ops.mesh.decimate` |

---

## Testing

### Unit Tests (24 tests - all passing)
- `tests/unit/tools/mesh/test_mesh_cleanup.py`
  - TestMeshDissolve: 9 tests (types, angle, options, validation)
  - TestMeshTrisToQuads: 5 tests (thresholds, error handling)
  - TestMeshNormalsMakeConsistent: 3 tests (outward, inward, errors)
  - TestMeshDecimate: 7 tests (ratio, symmetry, validation)

### E2E Tests (not run - requires addon rebuild)
- `tests/e2e/tools/mesh/test_mesh_cleanup.py`
  - dissolve tests (limited, custom angle, verts)
  - tris_to_quads tests (default, custom thresholds)
  - normals tests (outward, inward)
  - decimate tests (ratio, symmetry)
  - Integration workflow tests (cleanup imported mesh, optimize high-poly, retopology prep)

---

## Workflow Integration

### Import Cleanup Workflow
```
1. Import mesh (OBJ/FBX)
2. mesh_select(action="all")
3. mesh_tris_to_quads()  # Convert triangles to quads
4. mesh_normals_make_consistent()  # Fix inverted faces
5. mesh_dissolve(dissolve_type="limited")  # Clean up unnecessary geometry
```

### LOD Generation Workflow
```
1. mesh_select(action="all")
2. mesh_decimate(ratio=0.5)  # LOD1: 50%
3. mesh_decimate(ratio=0.25)  # LOD2: 25%
```

### Boolean Cleanup Workflow
```
1. After boolean operation...
2. mesh_select(action="all")
3. mesh_dissolve(dissolve_type="limited", angle_limit=5.0)
4. mesh_normals_make_consistent()
5. mesh_merge_by_distance()  # Remove doubles
```

---

## Semantic Tags

All tools use proper semantic tagging:
- `mesh_dissolve`: `[EDIT MODE][SELECTION-BASED][DESTRUCTIVE]`
- `mesh_tris_to_quads`: `[EDIT MODE][SELECTION-BASED][DESTRUCTIVE]`
- `mesh_normals_make_consistent`: `[EDIT MODE][SELECTION-BASED][NON-DESTRUCTIVE]`
- `mesh_decimate`: `[EDIT MODE][SELECTION-BASED][DESTRUCTIVE]`
