# Changelog: TASK-036 - Symmetry & Advanced Fill Tools

**Date:** 2025-12-05
**Task:** [TASK-036](../_TASKS/TASK-036_Symmetry_Advanced_Fill.md)
**Category:** Mesh Tools

---

## Summary

Implemented 5 mesh tools for symmetry and advanced fill operations:

| Tool | Description |
|------|-------------|
| `mesh_symmetrize` | Makes mesh symmetric by mirroring one side to the other |
| `mesh_grid_fill` | Fills boundary with a grid of quads (superior to triangle fill) |
| `mesh_poke_faces` | Pokes selected faces (adds vertex at center, creates triangle fan) |
| `mesh_beautify_fill` | Rearranges triangles to more uniform triangulation |
| `mesh_mirror` | Mirrors selected geometry within the same object |

---

## New MCP Tools

### 1. mesh_symmetrize

```python
mesh_symmetrize(
    direction: Literal["NEGATIVE_X", "POSITIVE_X", "NEGATIVE_Y", "POSITIVE_Y", "NEGATIVE_Z", "POSITIVE_Z"] = "NEGATIVE_X",
    threshold: float = 0.0001
) -> str
```

**Use Cases:**
- Fixing asymmetric character models
- Creating symmetric objects from half-models
- Repair after asymmetric edits

### 2. mesh_grid_fill

```python
mesh_grid_fill(
    span: int = 1,
    offset: int = 0,
    use_interp_simple: bool = False
) -> str
```

**Use Cases:**
- Filling holes with proper quad topology
- Creating subdivision-ready hole caps
- Better alternative to triangle fill for complex holes

### 3. mesh_poke_faces

```python
mesh_poke_faces(
    offset: float = 0.0,
    use_relative_offset: bool = False,
    center_mode: Literal["MEDIAN", "MEDIAN_WEIGHTED", "BOUNDS"] = "MEDIAN_WEIGHTED"
) -> str
```

**Use Cases:**
- Creating spikes/cones
- Preparing for subdivision patterns
- Artistic effects

### 4. mesh_beautify_fill

```python
mesh_beautify_fill(
    angle_limit: float = 180.0
) -> str
```

**Use Cases:**
- Cleaning up boolean operation results
- Improving triangulated imports
- Post-triangulation cleanup

### 5. mesh_mirror

```python
mesh_mirror(
    axis: Literal["X", "Y", "Z"] = "X",
    use_mirror_merge: bool = True,
    merge_threshold: float = 0.001
) -> str
```

**Use Cases:**
- Duplicating symmetric parts
- Creating mirrored elements
- Alternative to symmetrize when preserving both sides

---

## Files Changed

### Server (MCP)
| File | Change |
|------|--------|
| `server/domain/tools/mesh.py` | Added 5 abstract methods |
| `server/application/tool_handlers/mesh_handler.py` | Added 5 RPC handler methods |
| `server/adapters/mcp/areas/mesh.py` | Added 5 MCP tool definitions |

### Blender Addon
| File | Change |
|------|--------|
| `blender_addon/application/handlers/mesh.py` | Added 5 implementation methods |
| `blender_addon/__init__.py` | Registered 5 RPC handlers |

### Router
| File | Change |
|------|--------|
| `server/router/infrastructure/tools_metadata/mesh/mesh_symmetrize.json` | NEW |
| `server/router/infrastructure/tools_metadata/mesh/mesh_grid_fill.json` | NEW |
| `server/router/infrastructure/tools_metadata/mesh/mesh_poke_faces.json` | NEW |
| `server/router/infrastructure/tools_metadata/mesh/mesh_beautify_fill.json` | NEW |
| `server/router/infrastructure/tools_metadata/mesh/mesh_mirror.json` | NEW |

---

## Related Existing Tools

- `mesh_fill_holes` - Simple hole filling (creates triangles)
- `mesh_bridge_edge_loops` - Connect two edge loops
- `modeling_add_modifier(type="MIRROR")` - Non-destructive mirror modifier

---

## Testing

- [ ] Unit tests for each tool
- [ ] E2E test: Create asymmetric mesh → symmetrize → verify symmetry
- [ ] E2E test: Create hole → grid_fill → verify quad topology
- [ ] Test boundary selection requirement for grid_fill
