IFC Bonsai MCP

IFC-Bonsai-MCP is an MCP server that connects AI language models with the Bonsai Blender add-on to read, create, and edit IFC models directly via high-level tool calls.

This repository is associated with the paper: MCP4IFC: IFC-Based Building Design using Large Language Models | Project Page · arXiv · Experiment Results

🚀 Highlights:

• AI-Driven BIM: Use natural language to create and edit IFC elements like walls, doors, roofs, and stairs directly within Blender.
• RAG-Powered Knowledge: Leverage a Retrieval-Augmented Generation system with a local vector index for instant, semantic search across IFC and IfcOpenShell documentation.
• Advanced Geometry Generation: Create complex 3D geometry using Python and Trimesh, with tools to convert procedural meshes into native IFC elements.
• Extensible Toolset: A comprehensive set of over 50 MCP tools for scene analysis, object manipulation, parametric creation, and knowledge retrieval.

Installation Guide

Prerequisites

• Blender 4.4+ with Bonsai Add-on 0.8.2+
• Python 3.10+ (ensure it's in your PATH)
• UV Package Manager: pip install uv
• Claude Desktop or any MCP-compatible client

Quick Installation

This is a quick overview of installation steps in the global Python environment. For more details or virtual environment setup, check the section below.

# 1. Clone and setup
git clone [REPOSITORY_URL] && cd [REPOSITORY_NAME]

# 2. Install dependencies
pip install uv
uv sync

# 3. Install Blender packages (automatic)
python scripts/install_blender_packages.py

# 4. Create the zip file of blender_addon folder manually or use the helper script:
python scripts/install.py --create-addon-zip
# Then: Blender → Edit → Preferences → Add-ons → Install → blender_addon.zip
# After installing the add-on: Go to Blender UI → Sidebar Add-On Panel → BlenderMCP → Click "Connect to MCP server"

# 5. Configure Claude Desktop (Edit Config in Settings → Developer)
# Add: 
# {
#   "mcpServers": {
#     "blender": {
#       "command": "python",
#       "args": ["-m", "blender_mcp.server"],
#     }
#   }
# }

# 6. (Optional) Setup knowledge base
uv run python scripts/init_knowledge_base.py
uv run python scripts/embedding_server.py --model sentence-transformers/all-MiniLM-L6-v2 --host 127.0.0.1 --port 8080 --normalize

Here is the workflow diagram in Claude Desktop for reference:

If there are any issues, please refer to the detailed installation steps below.

Step-by-Step Installation

• Step 1: Clone and navigate to the project

  git clone [REPOSITORY_URL]
  cd [REPOSITORY_NAME]
  

• Step 2: Create and set up the virtual environment. This is for the MCP server that will run in the system/virtual environment.

  uv sync
  # Creates virtual environment: If `.venv/` doesn't exist, it creates one and installs all dependencies
  # Uses lock file: Ensures exact same versions as specified in `uv.lock`
  # Check https://docs.astral.sh/uv/ for using custom venv paths or names.
  

  Activate the virtual environment:

  source .venv/bin/activate    # Linux/macOS
  .venv\Scripts\activate       # Windows
  

  (Alternative) For a global installation, install all dependencies in your system Python environment:

  uv pip install . # records the install in uv.lock
  pip install .    # or, with pip
  

• Step 3: Install Blender-specific packages (Required). These are required for the Blender add-on to function correctly.

  The MCP server runs in your system's Python environment, but the Blender add-on runs inside Blender's Python environment. Some packages need to be installed specifically in Blender:

  • Option A: Automatic Installation (Recommended) using the helper script:

    python scripts/install_blender_packages.py
    

    This script automatically finds your Blender installation(s), installs all required packages (ifcopenshell, trimesh, pillow, numpy), and tests that everything works correctly

  • Option B: Manual Installation

    # Navigate to Blender's Python directory (adjust path for your Blender installation)
    # Windows (typical path):
    cd "C:\Program Files\Blender Foundation\Blender 4.4\4.4\python\bin"
    
    # Install required packages for Blender add-on
    python.exe -m pip install ifcopenshell>=0.7.0
    python.exe -m pip install trimesh>=3.24.0  
    python.exe -m pip install pillow>=10.0.0
    python.exe -m pip install numpy>=1.26.0
    

  • Option C: Using Blender's Console

    # 1. Open Blender
    # 2. Go to Scripting workspace
    # 3. Run this in the Python console:
    import subprocess
    import sys
    subprocess.check_call([sys.executable, "-m", "pip", "install", "ifcopenshell>=0.7.0", "trimesh>=3.24.0", "pillow>=10.0.0", "numpy>=1.26.0"])
    

Blender Add-on Packaging

The Blender add-on enables communication between Blender and the MCP server. To install it:

1. Create a zip file of the blender_addon folder
   • Either manually or run python scripts/install.py --create-addon-zip
2. In Blender, go to Edit > Preferences > Add-ons > Install...
3. Select the blender_addon.zip file and activate the add-on
4. In the main Blender UI, open Sidebar Add-On Panel → BlenderMCP → Connect to MCP server. Check /figs/workflow.png for reference.

Configuring Claude Desktop

For Virtual Environment Installation

If you installed using a virtual environment, you need to point Claude to the Python executable in the virtual environment:

1. Open Claude Desktop > Settings > Developer > Edit Config File.
2. Add this configuration:

   {
     "mcpServers": {
       "blender": {
         "command": "C:\\path\\to\\ifc-bonsai-mcp\\.venv\\Scripts\\python.exe",
         "args": ["-m", "blender_mcp.server"],
       }
     }
   }
   

   Note: On Windows, use double backslashes (\\) in file paths. On macOS and Linux, use forward slashes (/).

For Global Installation

If you installed globally, use the system Python:

{
  "mcpServers": {
    "blender": {
      "command": "python",
      "args": ["-m", "blender_mcp.server"],
    }
  }
}

3. Important: Replace C:/path/to/ifc-bonsai-mcp with your actual project path
4. Restart Claude Desktop

Running the MCP Server

Important: Since the project tries to save to an IFC file and loads it, always create an empty file and save it before doing any operations. Because the MCP server directly loads the IFC file and does the edits. If a new project is created and no .ifc file is saved, then the MCP server will not update in the actual blender scene. Just do ctrl (cmd) + S and save an empty IFC file if a new project is created.

If there are connection issues please check if the "Connect to MCP server" button in the Blender add-on panel has been clicked. Check the /figs/workflow.png to see where it is located.

Code Execution Limitations: The general execute_code tool behaves unpredictably with IFC operations. The general execute code tool lacks proper context handling, cannot save changes back to the model consistently and may produce unsafe results for IFC operations. Consider disabling the general execute_code tool if there are issues.

Knowledge Base & Embeddings

The MCP server includes a RAG-powered tool to query IFC documentation and best practices. This uses a local ChromaDB index and an embedding model (Sentence Transformers). To use the RAG-powered IFC knowledge base, follow these steps:

• Initialize the Local Chroma Index

  uv run python scripts/init_knowledge_base.py
  

  This downloads the embedding model (Sentence Transformers) and caches the IFC knowledge base under .cache/chromadb/.

• Run the embedding model so the MCP server can use it for embedding generation:

  uv run python scripts/embedding_server.py --model sentence-transformers/all-MiniLM-L6-v2 --host 127.0.0.1 --port 8080 --normalize
  

  This starts a local embedding server that the MCP server can use for embedding generation. Adjust the model and port as needed. If the port is changed, the BLENDER_MCP_REMOTE_EMBEDDINGS_URL environment variable must be set accordingly.

List of Available Tools

The MCP server has various tools that can be called by the AI assistant. All available tools and their parameters are documented in the API Reference.

Click to expand the summary of the available tools:

Tool Name	Description
Analysis Tools
capture_blender_window_screenshot	Capture high-quality screenshot of entire Blender window
capture_blender_3dviewport_screenshot	Capture screenshot of only the 3D viewport area
API Tools
execute_blender_code	Execute arbitrary Python code in Blender context
list_blender_commands	List all available Blender addon commands
execute_ifc_code_tool	Execute IFC OpenShell code with security restrictions
get_scene_info	Get basic information about current Blender scene
get_blender_object_info	Get detailed Blender information about specific object
get_selected_objects	Get list of currently selected objects with GUID info
get_object_info	Get IFC object information from GUIDs or selection
get_ifc_scene_overview	Get comprehensive IFC scene overview
create_wall	Create parametric IFC wall with full control
create_two_point_wall	Create wall between two 3D points
create_polyline_walls	Create connected walls along polyline path
update_wall	Update existing wall properties using GUID
get_wall_properties	Get properties of existing wall by GUID
get_roof_types	Get all supported roof types and descriptions
create_roof	Create parametric IFC roof from polyline outline
update_roof	Update existing roof properties and regenerate geometry
delete_roof	Delete one or more roofs with comprehensive cleanup
create_slab	Create parametric IFC slab with custom geometry
update_slab	Update existing slab geometric properties
get_slab_properties	Get comprehensive properties of existing slab
get_door_operation_types	Get all supported door operation types
create_door	Create parametric IFC door with detailed properties
update_door	Update existing door properties using GUID
get_door_properties	Get properties of existing door by GUID
get_window_partition_types	Get all supported window partition types
create_window	Create parametric IFC window with customization
update_window	Update existing window properties using GUID
get_window_properties	Get detailed properties of existing window
create_trimesh_ifc	Execute Trimesh code and create IFC element
get_stairs_types	Get all supported stairs types and IFC mappings
create_stairs	Create parametric IFC stairs with various types
update_stairs	Update existing stairs properties and geometry
delete_stairs	Delete one or more stairs by their GUIDs
create_surface_style	Create basic surface style with color/transparency
create_pbr_style	Create PBR style with advanced material properties
apply_style_to_object	Apply style directly to IFC objects
list_styles	List all available styles in current IFC model
update_style	Update properties of existing style
remove_style	Remove style from the model
create_mesh_ifc	Create IFC element from JSON mesh data
list_ifc_entities	List valid IFC entity classes for mesh generation
get_trimesh_examples	Get comprehensive Trimesh code examples
RAG Tools
ensure_ifc_knowledge_ready	Initialize IFC knowledge system for local model
search_ifc_knowledge	Search IFC knowledge base with semantic search
get_ifc_knowledge_status	Get current status of IFC knowledge base system
find_ifc_function	Find IFC functions by operation and object type
get_ifc_module_info	Get detailed information about specific IFC module
get_ifc_function_details	Get comprehensive details about specific IFC function
clear_ifc_knowledge_cache	Clear cached IFC knowledge data
get_cache_statistics	Get detailed cache usage statistics

Contributing

Pull requests are welcome! See CONTRIBUTING.md for the development workflow and TROUBLESHOOTING.md for any issues.

Acknowledgements

This is not an official Blender, Bonsai or IfcOpenShell project. Thanks to BlenderMCP and Bonsai_mcp for their open source work.

Citation

Please consider citing our work if you find it useful or used in your research.

@misc{nithyanantham2025mcp4ifcifcbasedbuildingdesign,
      title={MCP4IFC: IFC-Based Building Design Using Large Language Models}, 
      author={Bharathi Kannan Nithyanantham and Tobias Sesterhenn and Ashwin Nedungadi and Sergio Peral Garijo and Janis Zenkner and Christian Bartelt and Stefan Lüdtke},
      year={2025},
      eprint={2511.05533},
      archivePrefix={arXiv},
      primaryClass={cs.CL},
      url={https://arxiv.org/abs/2511.05533}, 
}