Flint: API Server for Blender MCP on macOS with visionOS Connectivity

Flint is a FastAPI-based server that integrates with the Blender MCP (Multimodal Capability Protocol) addon, enabling the generation and export of 3D models from text prompts using Claude. This guide provides step-by-step instructions for setting up and running an MCP server on macOS, configured to work with visionOS. To use Flint you will require an API key for accessing Claude.

Overview

This project provides an API service that:

1. Takes text prompts describing 3D models
2. Uses Claude and MCP to generate Blender scenes
3. Exports the resulting 3D models as USDZ files
4. Provides an endpoint to download the exported models

Prerequisites

• macOS operating system
• Homebrew package manager 4.5.0+
• Python 3.11+
• Blender 4.4.1 (latest stable version recommended)
• pip (Python package manager) pip 25+
• Blender MCP addon from blender-mcp repository

Initial Setup

1. Install Blender MCP Addon

Before proceeding with the API server installation, you need to set up the Blender MCP addon:

1. Clone or download the Blender MCP repository:

git clone https://github.com/ahujasid/blender-mcp.git

2. Add and enable the addon in Blender:
   • Open Blender
   • Go to Edit > Preferences > Add-ons
   • Click on Add-ons Settings and then Install from Disk
   • Select the addon.py file from the downloaded repository
   • Find and enable the MCP addon
   • Save preferences

Installation

After completing the initial setup with the Blender MCP addon, follow these steps to install the API server:

2. Clone the repository

Clone the repo and move to the Flint Server folder

cd Flint-Server

3. Create and activate a virtual environment

python3 -m venv .venv

source .venv/bin/activate

4. Install required Python packages

pip install fastapi uvicorn python-dotenv pydantic langchain langchain-anthropic mcp-use fastembed

5. Install MCP dependencies

# Install UVX CLI tool
brew install uv

6. Add your own Claude API Key

Create an .env file in the project root add your own API Key:

ANTHROPIC_API_KEY=your_anthropic_api_key

7. Configure file paths

Edit api_server.py to update the following paths according to your macOS system:

# Change these to your real full paths!
EXPORT_FOLDER = "/path/to/your/exports/folder"
BLENDER_PATH = "/Applications/Blender.app/Contents/MacOS/Blender"

Make sure the BLENDER_PATH points to your Blender installation on macOS, which is typically located at /Applications/Blender.app/Contents/MacOS/Blender.

Add your mac ip address in this line:

file_url = f"<Your-ip-address>:8000/download/{EXPORT_FILENAME}"

Edit esport_model.py to update the following paths according to your macOS system:

output_path = "/Users/../../exported_model.usdz"

Usage

Start the server

uvicorn api_server:app --reload --host 0.0.0.0 --port 8000

Generate a 3D model

Send a POST request to the /run endpoint:

curl -X POST "http://localhost:8000/run" \
  -H "Content-Type: application/json" \
  -d '{"prompt": "Create a low-poly tree with green leaves and a brown trunk"}'

The response will include the result and a URL to download the exported model.

Download the model

Use the returned URL or access directly:

http://localhost:8000/download/exported_model.usdz

If it does not work substitute localhost with your personal Mac IP address

API Endpoints

POST /run

Generates a 3D model based on a text prompt.

Request Body:

{
  "prompt": "Description of the 3D model to create"
}

Response:

{
  "result": "MCP agent execution result",
  "model_url": "URL to download the generated model"
}

GET /download/{filename}

Downloads a generated model file.

Connection with visionOS

Once the server is running correctly on your Mac and Blender is open with the add-on installed, you can launch the visionOS app—either on the simulator or a physical device. Modify the url property in the ViewModel.swift file adding your Mac IP Address.

As soon as the app opens, enter your prompt into the text field and tap the button. If everything is set up properly, the model will appear in the space within a few seconds.

Troubleshooting

Common Issues

1. Blender not found: Ensure the BLENDER_PATH is correctly set to your Blender executable location on macOS.

2. MCP errors: Make sure you have properly installed the Blender MCP addon from the GitHub repository and enabled it in Blender preferences.

3. File permission issues: Ensure the export directory is writable by the user running the server.

Logs

Check the server console output for detailed logs and error messages.

License

MIT License

Acknowledgements

• This project uses Anthropic's Claude for natural language processing
• Multimodal Capability Protocol (MCP) for Blender integration
• FastAPI for the web server framework