RhinoMCP: an MCP Server for Rhino 3D

105 tools for AI-driven 3D modeling, analysis, diagnostics, and Grasshopper integration via the Model Context Protocol.

RhinoMCP connects Claude to Rhino 3D through a comprehensive set of tools covering everything from basic primitives to advanced surface modeling (loft, sweep, revolve), boolean operations, mesh diagnostics, block management, and parametric design with Grasshopper.

Architecture

┌────────────────┐   stdio    ┌──────────────┐   TCP/JSON    ┌──────────────┐
│ Claude Desktop │◄──────────►│  rhino_mcp   │◄─────────────►│    Rhino 3D  │
│                │   (MCP)    │  (Python)    │  localhost:   │  listener.py │
│                │            │  server.py   │    9876       │  (inside     │
└────────────────┘            └──────────────┘               │   Rhino)     │
                                                             └──────────────┘

MCP Server (rhino_mcp/). Python package using FastMCP. Communicates with Claude via stdio and with Rhino via TCP.

Rhino Listener (rhino/listener.py). Python script that runs inside Rhino. Opens a TCP server, receives JSON commands, executes them using RhinoCommon/rhinoscriptsyntax, and returns results.

Related MCP server: Grasshopper MCP

Capabilities

Geometry Creation (21 tools)

Transforms (8 tools)

move, rotate, scale, scale_non_uniform, mirror, copy, array_linear, array_polar

Boolean Operations (3 tools)

boolean_union, boolean_difference, boolean_intersection

Modification (18 tools)

Blocks & Instances (4 tools)

create_block, insert_block, list_blocks, explode_block

User Data (2 tools)

set_user_text, get_user_text: store metadata, BIM data, costs, etc.

Layers (6 tools)

list_layers, create_layer, delete_layer, set_layer_color, set_layer_visibility, set_current_layer

Materials (3 tools)

list_materials, create_material, assign_material

Analysis (10 tools)

Diagnostics (4 tools)

View (5 tools)

zoom_extents, set_view, capture_view (with base64 option), list_views, set_display_mode

Grasshopper (3 tools)

gh_run_script, gh_set_slider, gh_get_outputs

Code Execution (2 tools)

run_python, run_command: full access to rhinoscriptsyntax and RhinoCommon

Undo/Redo (2 tools)

undo, redo

Scene (4 tools)

scene_info, get_objects, get_object (detailed with edge info), select_objects

Import/Export (2 tools)

export (.3dm, .obj, .stl, .step, .iges, .fbx), import_file

Bold = new in v2.0

Prerequisites

• Rhino 7 or 8 (Windows or Mac)

• Python 3.10+

• uv package manager (install)

Installation

1. Clone and install

git clone https://github.com/kbangaru-cyber/rhino-mcp.git
cd Rhino_MCP
uv sync

2. Start the Rhino listener

In Rhino:

1. Go to Tools > PythonScript > Run

2. Select rhino/listener.py

3. You should see:

============================================================
  RhinoMCP Listener v2.0.0
  Listening on 127.0.0.1:9876
  Registered handlers: 90
  Ready for MCP connection (Claude)
============================================================

3. Configure Claude Desktop

Claude Desktop

Edit claude_desktop_config.json:

{
  "mcpServers": {
    "rhino": {
      "command": "uv",
      "args": ["--directory", "/ABSOLUTE/PATH/TO/Rhino_MCP", "run", "rhino-mcp"],
      "env": {
        "RHINO_MCP_HOST": "127.0.0.1",
        "RHINO_MCP_PORT": "9876",
        "RHINO_MCP_TIMEOUT": "30"
      }
    }
  }
}

Usage Examples

Create a simple building form

"Create a 10x8x4 meter box for the building volume, then add a cylinder of radius 2 and height 6 at the center for a tower. Union them together and fillet all edges with radius 0.3."

Diagnose model problems

"Check all objects in the scene for problems. Find any naked edges and tell me what needs fixing."

Parametric design

"Create a vase shape by making a profile curve and revolving it. Then create a polar array of decorative cylinders around it."

Built-in Prompts

RhinoMCP includes guided workflow prompts:

• model-from-description: structured workflow for creating 3D models from text descriptions

• diagnose-model: systematic approach to finding and fixing model problems

• parametric-design: guide for Grasshopper/parametric workflows

Resources

The server exposes live data as MCP resources:

Configuration

Development

# Install dev dependencies
uv sync --extra dev

# Run tests (no Rhino needed)
uv run pytest -v

# Lint
uv run ruff check .

# Type check
uv run mypy rhino_mcp

Integration testing

With Rhino running and the listener active:

uv run pytest -v -m integration

Protocol

Commands are JSON objects sent over TCP (newline-delimited):

{"id": "abc123", "action": "create_sphere", "params": {"center": [0,0,0], "radius": 5}}

Responses:

{"id": "abc123", "ok": true, "result": {"guid": "d3e4f5..."}}

Thread Safety

The Rhino listener uses Rhino.RhinoApp.InvokeOnUiThread() on Rhino 8+ to ensure all geometry operations run on the UI thread. On Rhino 7, operations execute directly (which is safe for single-client connections).

License

MIT. See LICENSE.

Author

Karthick Raja B G, portfolio · GitHub

Related work: SPIDER, a Grasshopper plugin for computational geometry and spatial analysis.