# Retopology Tools Implementation Summary
## Overview
This document summarizes the retopology tools implementation for the BlenderMCP project. The implementation follows Behavior-Driven Development (BDD) principles with Gherkin specifications.
## Implemented Features
### ✅ BDD #1: MCP Contract (Listing & Discovery)
**Status:** Fully Implemented
- MCP tools are properly registered and discoverable
- Tools include JSON schemas with typed parameters
- Resources and prompts are exposed per MCP spec
- Feature file: `features/01_mcp_contract.feature`
### ✅ BDD #2: Mesh Analysis
**Status:** Fully Implemented
**Addon Methods (addon.py):**
- `mesh_stats(active_only)` - Returns topology metrics, tri/quad/ngon counts, non-manifold edges, surface area, volume
- `detect_topology_issues(angle_sharp, distance_doubles)` - Detects non-manifold edges, loose geometry, duplicates, inverted normals
**MCP Tools (server.py):**
- `mesh_stats` tool with formatted output
- `detect_topology_issues` tool with helpful suggestions
**Feature file:** `features/02_mesh_analysis.feature`
### ✅ BDD #3: Voxel Remesh
**Status:** Fully Implemented
**Addon Method (addon.py):**
- `voxel_remesh(voxel_size, adaptivity)` - Uses REMESH modifier with VOXEL mode
**MCP Tool (server.py):**
- `voxel_remesh` tool with before/after face counts
**Feature file:** `features/03_voxel_remesh.feature`
### ✅ BDD #4: QuadriFlow Remesh
**Status:** Fully Implemented
**Addon Method (addon.py):**
- `quadriflow_remesh(target_faces, adaptivity, preserve_sharp)` - Uses bpy.ops.object.quadriflow_remesh()
- Includes precondition checking for manifold mesh and consistent normals
- Returns helpful error messages with fix suggestions
**MCP Tool (server.py):**
- `quadriflow_remesh` tool with precondition documentation in docstring
**Feature file:** `features/04_quadriflow_remesh.feature`
### ✅ BDD #5: Decimation
**Status:** Fully Implemented
**Addon Method (addon.py):**
- `decimate(ratio, mode, angle_limit)` - Supports COLLAPSE, DISSOLVE, UNSUBDIVIDE modes
- Calculates actual ratio achieved
**MCP Tool (server.py):**
- `decimate` tool with mode-specific configuration
**Feature file:** `features/05_decimation.feature`
### ✅ BDD #6: Shrinkwrap Projection
**Status:** Fully Implemented
**Addon Method (addon.py):**
- `shrinkwrap_reproject(high, low, method, offset)` - Supports multiple projection methods
- Validates object existence
**MCP Tool (server.py):**
- `shrinkwrap_reproject` tool with method documentation
**Feature file:** `features/06_shrinkwrap.feature`
### ✅ BDD #7: Seams & Shading Helpers
**Status:** Fully Implemented
**Addon Methods (addon.py):**
- `mark_seams_by_angle(angle, clear_existing)` - Auto-marks UV seams
- `mark_sharp_by_angle(angle, clear_existing)` - Marks sharp edges for shading
**MCP Tools (server.py):**
- `mark_seams_by_angle` tool
- `mark_sharp_by_angle` tool
**Feature file:** `features/07_seams_shading.feature`
### ✅ BDD #8: Viewport Controls
**Status:** Fully Implemented
**Addon Methods (addon.py):**
- `set_view_projection(projection)` - Toggle ORTHO/PERSP
- `align_view_to_axis(axis, side)` - Snap to Front/Back/Left/Right/Top/Bottom
- `frame_selected()` - Frame selected objects in viewport
**MCP Tools (server.py):**
- `set_view_projection` tool
- `align_view_to_axis` tool
- `frame_selected` tool
**Feature file:** `features/08_viewport_controls.feature`
### ✅ Retopo Pipeline Prompt
**Status:** Fully Implemented
**MCP Prompt (server.py):**
- `retopo_pipeline` prompt with complete guided workflow
- Includes Phase 1-5: Analysis, Remeshing, Refinement, Inspection, Export
- Common workflow examples for different use cases
- Tips and best practices
### ✅ Documentation
**Status:** Fully Implemented
**README.md Updates:**
- Retopology features section with tool listing
- Complete retopology guide with:
- Quick start with retopo pipeline prompt
- 3 manual workflows (Character, Scan, Hard-Surface)
- Tool reference tables
- Important notes and preconditions
- Best practices
- Common issues and solutions
- BDD specification references
**Feature Files:**
- 8 comprehensive Gherkin feature files documenting all scenarios
- Scenario outlines with examples
- Clear Given/When/Then structure
## Architecture (Post-Refactoring)
### 🏗️ Модульная структура
После рефакторинга код организован по модулям:
```
src/
├── server.py (763 lines) - только обёртки с @mcp.tool()
├── tools/ - логика инструментов
│ ├── mesh_analysis.py - mesh_stats, detect_topology_issues
│ ├── remeshing.py - voxel_remesh, quadriflow_remesh, decimate, shrinkwrap_reproject
│ ├── viewport.py - set_view_projection, align_view_to_axis, frame_selected
│ ├── shading.py - mark_seams_by_angle, mark_sharp_by_angle
│ ├── scene.py - get_scene_info, get_object_info, etc.
│ └── integrations/ - polyhaven.py, sketchfab.py, hyper3d.py
└── prompts/ - retopo.py, asset_creation.py
```
**Принцип:** server.py содержит ТОЛЬКО импорты и тонкие обёртки. Вся логика - в отдельных модулях.
Подробнее см. [ARCHITECTURE.md](./ARCHITECTURE.md)
## Files Modified
### Core Implementation Files
**D:\repos\blender-mcp\addon.py**
- Added bmesh import
- Added 11 new methods to BlenderMCPServer class:
- mesh_stats
- detect_topology_issues
- voxel_remesh
- quadriflow_remesh
- decimate
- shrinkwrap_reproject
- mark_seams_by_angle
- mark_sharp_by_angle
- set_view_projection
- align_view_to_axis
- frame_selected
- Updated handlers dictionary with all new methods
**D:\repos\blender-mcp\src\server.py**
- Added 11 MCP tools corresponding to addon methods
- Added retopo_pipeline prompt
- All tools include comprehensive docstrings
- Formatted output for better readability
**D:\repos\blender-mcp\README.md**
- Added Retopology Features section
- Added comprehensive Retopology Guide section
- Updated feature list
### New Files Created
**Feature Specifications (Gherkin):**
- `features/01_mcp_contract.feature`
- `features/02_mesh_analysis.feature`
- `features/03_voxel_remesh.feature`
- `features/04_quadriflow_remesh.feature`
- `features/05_decimation.feature`
- `features/06_shrinkwrap.feature`
- `features/07_seams_shading.feature`
- `features/08_viewport_controls.feature`
- `features/09_baking.feature` (specification only)
- `features/10_import_export.feature` (specification only)
- `features/11_viewport_resource.feature` (specification only)
- `features/12_safety.feature` (specification only)
- `features/13_model_switching.feature` (specification only)
- `features/14_camera_ortho.feature` (specification only)
- `features/15_batch_ortho_renders.feature` (specification only)
**Module Structure:**
- `src/retopo_tools/__init__.py`
- `src/retopo_tools/mesh_analysis.py` (tool definitions)
## Not Yet Implemented (Future Work)
### ⏭️ BDD #9: Baking (Normals)
**Feature file:** `features/09_baking.feature`
**Planned functionality:**
- `bake_normals(high, low, map_size, space, cage)` - Bake normal maps from high to low poly
- Automatic material setup with normal map node
- Texture directory creation
- Support for tangent and object space
**Implementation requirements:**
- Blender baking operations (bpy.ops.object.bake)
- Material node setup
- UV validation
- Cage object handling
### ⏭️ BDD #10: Import/Export
**Feature file:** `features/10_import_export.feature`
**Planned functionality:**
- `import_reference(paths)` - Import reference meshes into "_ref" collection
- `export_asset(format, path, scale, apply_modifiers)` - Export game-ready assets
- Format support: GLTF, FBX, OBJ
- Modifier application
- Scale adjustment
**Implementation requirements:**
- File I/O operations
- Collection management
- Format-specific export options
### ⏭️ BDD #11: Viewport Screenshot as Resource
**Feature file:** `features/11_viewport_resource.feature`
**Status:** Partially implemented
- Existing `get_viewport_screenshot` tool works
- Need to add preset support (wire, matcap, lit)
- Need to expose as MCP Resource (not just tool)
### ⏭️ BDD #12: Safety & Arbitration
**Feature file:** `features/12_safety.feature`
**Planned functionality:**
- `execute_blender_code` requires `confirm=true` flag
- Safety warnings and logging
- Documentation of security risks
**Implementation requirements:**
- Parameter validation in addon.py execute_code method
- Warning messages
- README security section
### ⏭️ BDD #13: Model Switching
**Feature file:** `features/13_model_switching.feature`
**Planned functionality:**
- `generate_client_config(provider, model)` - Generate client configs for different LLM providers
- Support for OpenRouter, Claude Desktop, Cursor
- Provider-agnostic documentation
**Implementation requirements:**
- Config file generation
- Template system for different providers
- Documentation clarifying MCP server is provider-agnostic
### ⏭️ BDD #14: Camera Orthographic Rendering
**Feature file:** `features/14_camera_ortho.feature`
**Planned functionality:**
- `set_camera_projection(projection, ortho_scale)` - Set camera to orthographic
- `align_camera_to_view()` - Align camera to current viewport
- Automatic ortho_scale calculation
- Clear documentation of viewport vs render projection
**Implementation requirements:**
- Camera manipulation (bpy.data.cameras)
- View-to-camera alignment
- Render settings
### ⏭️ BDD #15: Batch Orthographic Renders
**Feature file:** `features/15_batch_ortho_renders.feature`
**Planned functionality:**
- `render_orthographic_views(views, width, height, output_path)` - Batch render standard views
- Support for all 6 orthographic views (Front, Back, Left, Right, Top, Bottom)
- Consistent camera setup across views
- Output directory creation
**Implementation requirements:**
- Render operations (bpy.ops.render)
- Camera alignment automation
- File path management
- Image format settings
## Architecture & Design Decisions
### Safe, Parameterized Tools
- All tools use typed parameters with validation
- No arbitrary code execution required for retopo workflows
- Clear error messages with suggested fixes
### Deterministic Behavior
- Tool names are consistent and descriptive
- All parameters have sensible defaults
- Return values follow consistent schema
### MCP Spec Compliance
- Tools registered with JSON schemas
- Resources declare correct MIME types
- Prompts provide guided workflows
- Discovery mechanism works per MCP spec
### Error Handling
- Precondition checks before operations
- Helpful error messages with fix suggestions
- Graceful degradation
### Documentation-Driven
- BDD feature files serve as specification
- README includes practical examples
- Docstrings document all parameters
- Common issues documented with solutions
## Testing Strategy
### Manual Testing Checklist
1. ✅ Connect to Blender addon
2. ✅ List tools via MCP (should see retopo tools)
3. ✅ Test mesh_stats on default cube
4. ✅ Test detect_topology_issues
5. ✅ Test voxel_remesh
6. ✅ Test quadriflow_remesh (verify manifold requirement)
7. ✅ Test decimate with different modes
8. ✅ Test viewport controls
9. ✅ Test seam/sharp marking
10. ✅ Use retopo_pipeline prompt
### Automated Testing (Future)
- Implement BDD test runners using feature files
- Mock Blender operations for unit tests
- Integration tests with real Blender instance
## Security Considerations
### Current Implementation
- All retopo tools are safe, parameterized operations
- No arbitrary code execution in retopo workflow
- execute_blender_code still exists for advanced users
### Future Enhancements
- Add `confirm=true` requirement to execute_blender_code
- Document security implications in README
- Consider sandboxing or additional safeguards
## Performance Considerations
- Mesh analysis uses bmesh for accurate topology inspection
- Large meshes may take time for remeshing operations
- Viewport operations are fast (no render overhead)
- QuadriFlow can be slow on very high-poly meshes
## Known Limitations
1. **QuadriFlow Preconditions**: Requires manifold mesh with consistent normals
2. **Voxel Remesh Data Loss**: Loses UV maps, vertex colors, and other data layers
3. **Approximate Counts**: QuadriFlow face count is approximate, not exact
4. **Platform-Specific**: Some operations may behave differently on different platforms
## Future Enhancement Ideas
1. **UV Unwrapping Tools**:
- `uv_unwrap(method)` - Smart UV unwrap
- `uv_pack_islands()` - Pack UV islands efficiently
2. **Advanced Baking**:
- Multiple map types (AO, curvature, thickness)
- Batch baking
3. **Topology Visualization**:
- Wireframe overlays
- Topology heat maps
4. **Automated Workflows**:
- One-click retopo for common scenarios
- Preset-based remeshing
5. **Quality Metrics**:
- Quad quality analysis
- Edge flow visualization
## Contributors
Implementation by Claude (Anthropic) following specifications provided by user.
## License
Follows the same license as the main BlenderMCP project.
