jingcheng-chen/rhinomcp

RhinoMCP – AI‑driven control of Rhino 3D & Grasshopper

What it is – A small open‑source bridge that lets large‑language‑model agents (Claude, Cursor, Codex, etc.) talk to Rhino 3D and its visual programming environment Grasshopper. It implements the Model Context Protocol (MCP) so the AI can issue high‑level commands in plain language and receive visual feedback from the Rhino viewport.

Key capabilities

• Geometry creation & editing – points, curves, surfaces, solids, booleans, lofts, sweeps, etc., either one‑by‑one or in batches.
• Scene inspection – query object lists, attributes, layers, or capture a screenshot of the current viewport for the model to “see”.
• Grasshopper scripting – search components, add them to a canvas, wire parameters, set slider values, run the solver, or rebuild an entire definition in a single call.
• Low‑level access – run any native Rhino command, execute RhinoScript‑Python, or run RhinoCommon C# code (with optional switches to disable these powerful tools).
• Two‑way interaction – the AI can both generate geometry and read back the model state, enabling iterative design loops.

How it works

1. Python MCP server (rhinomcp on PyPI) runs locally and exposes the tool set over the standard MCP stdio interface.
2. Rhino plugin (installed via Rhino’s Package Manager) starts a TCP listener inside Rhino (default 127.0.0.1:1999).
3. An AI client registers the server as an MCP endpoint (rhino) and sends JSON‑encoded tool calls; the plugin executes them on the main Rhino thread and returns results.

Getting started

1. Install the Rhino plugin from the Package Manager (rhinomcp).
2. Install the Python server with uvx rhinomcp@latest (or via pip install rhinomcp).
3. Add the server to your AI client’s MCP config (e.g., codex mcp add rhino …).
4. In Rhino, run the command mcpstart to open the TCP bridge.
5. Chat with your assistant: ask it to “create a 6×6×6 grid of boxes with a blue‑to‑red gradient” or “build a Grasshopper graph that places cylinders whose height follows distance to a point”.

Who it’s for – Designers, architects, engineers, or developers who already use Rhino 8 and want to experiment with AI‑assisted modeling or automate Grasshopper workflows. It is also useful for researchers building autonomous design agents.

Project status – Actively maintained (PyPI releases, Rhino plugin updates via the Package Manager). The repository includes a Python test suite, C# build scripts, and documentation for extending the tool set.

License – MIT.