# blender-mcp-2.79 — Blender 2.79 compatibility fork

This is a fork of [ahujasid/blender-mcp](https://github.com/ahujasid/blender-mcp) (MIT licensed, © 2025 Siddharth Ahuja — see [LICENSE](LICENSE)), patched so **`addon.py` also runs on Blender 2.79** (Python 3.7). Upstream requires Blender 3.0+ / Python 3.10+; this fork exists for people who still run 2.79 for legacy tooling (e.g. [Korman](https://github.com/H-plus-Time/korman) Myst-engine modding) and want the same MCP control there.

**What changed, and why:**

| Upstream (2.80+/3.10+ only) API | Problem on Blender 2.79 / Python 3.7 | Fix in this fork |
|---|---|---|
| `match` / `case` statements | `SyntaxError` — needs Python 3.10+ | Rewritten as `if`/`elif`/`else` |
| `list[tuple[str, str]]` generic type hints in function signatures | `TypeError: 'type' object is not subscriptable` at *def* time — needs Python 3.9+ (PEP 585) | Added `from __future__ import annotations` (PEP 563, available since 3.7) so annotations are lazily evaluated |
| `str.removeprefix()` | `AttributeError` — needs Python 3.9+ | Manual `startswith`/slice fallback |
| `bpy.context.view_layer` | Doesn't exist before Blender 2.80 | `hasattr`-gated shim → falls back to `bpy.context.scene.objects.active` / `scene.update()` |
| `bpy.context.collection.objects.link(obj)` | Doesn't exist before Blender 2.80 (no collections) | Shim → falls back to `bpy.context.scene.objects.link(obj)` |
| `obj.select_set(True)` | Doesn't exist before Blender 2.80 | Shim → falls back to `obj.select = True` |
| `bpy.context.temp_override(...)` | Doesn't exist before Blender 3.2 | Shim → falls back to legacy dict-based operator context override |
| Material/world `use_nodes = True` alone | 2.79 defaults to the Blender Internal render engine, so node trees aren't actually used unless the engine is Cycles | Shim also forces `scene.render.engine = 'CYCLES'` on pre-2.80 before enabling nodes |
| `gpu.types.GPUOffScreen.draw_view3d(...)` (viewport screenshot) | 2.79's `gpu` module predates this API entirely, no equivalent exists | On 2.79 this skips straight to the existing `window_grab` fallback (`bpy.ops.screen.screenshot_area`) rather than throwing |
| `bpy.app.timers.register(...)` (hops the incoming command from the socket thread onto Blender's main thread) | Doesn't exist before Blender 2.80 — this is architectural, not a rename | On 2.79, commands are pushed onto a thread-safe queue and drained by a modal operator (`BLENDERMCP_OT_MainThreadPump`) driven by `event_timer_add`, the pre-2.80 equivalent |
| `bpy.types.blendermcp_server = ...` (stashing the running-server singleton) | Blender 2.79's `bpy.types` (`RNA_Types`) doesn't allow arbitrary attribute assignment the way 2.80+ does | Replaced with a plain module-level global (`_blendermcp_server`), which works identically on every version |

All of the above are `hasattr`/version-gated, so **this same `addon.py` still works unmodified on modern Blender (3.0–5.x)** — nothing upstream-compatible was removed, only extended. The MCP server/client half of this repo (`src/blender_mcp/`, the part launched via `uvx blender-mcp`) is **unchanged from upstream** — it's a separate, modern Python process (run via `uv`, not inside Blender) that just speaks the same JSON-over-TCP protocol to whichever `addon.py` is running inside Blender, so it works identically against a 2.79 or a 5.x Blender instance.

### Getting true zero-click auto-start on Blender 2.79

On 2.80+, upstream auto-starts the socket server the instant the addon registers, using `bpy.app.timers` to safely hand control to the main thread — no user action needed. On 2.79, the underlying **TCP server still auto-starts on launch** (confirmed working — it doesn't need the timer API), but the **main-thread command pump does not**, because invoking any operator (including our modal pump) during addon registration hits Blender's restricted startup context (`_RestrictContext`, which lacks `.scene` and rejects `bpy.ops` calls).

This fork tries two automatic in-addon fallbacks — a `load_post` hook and a `scene_update_post` hook — but **don't rely on either**: `load_post` for the very first startup file load fires *before* addons finish registering ([this is a known, documented Blender limitation, not a bug in this fork — see T34636](https://developer.blender.org/T34636)), so appending a handler during `register()` is always too late for that specific event. `scene_update_post` only fires on an actual scene data mutation — on a genuinely idle session (no file opened, nothing touched) it may not fire for 30+ seconds, if at all.

**The confirmed-reliable fix: launch Blender with the bundled `--python` script.**

```
blender --python autostart_2.79.py
```

or double-click `launch_with_mcp.bat` (edit the `BLENDER_EXE` path inside it first to point at your own Blender 2.79 install). Scripts passed via `--python` run *after* Blender's full startup completes, in a normal non-restricted context — this is the standard, well-established pattern for unattended/pipeline Blender automation, and it starts the connection within a few seconds of launch with zero clicks. Verified end-to-end against a live session (auto-started, then a full round-trip `execute_code` call created and returned a real object).

If you'd rather not use a custom launcher, the fallback is a single manual step: click **"Connect to Claude"** once in the sidebar (`View3D > N-panel > BlenderMCP` tab) after Blender opens. It only takes one click per session.

One gotcha either way: if you load a *different* .blend file mid-session (`File > Open` or `bpy.ops.wm.open_mainfile`), Blender cancels the running modal pump along with it, and — since the pump is what lets `execute_code` run at all — you can't restart it through the same now-stuck MCP connection. Restart Blender with the target file passed directly (`blender your_file.blend --python autostart_2.79.py`) rather than opening it from within a running session.

Everything below this point is upstream's original README.

---

# BlenderMCP - Blender Model Context Protocol Integration
<a href="https://trendshift.io/repositories/14834?utm_source=repository-badge&amp;utm_medium=badge&amp;utm_campaign=badge-repository-14834" target="_blank" rel="noopener noreferrer"><img src="https://trendshift.io/api/badge/repositories/14834" alt="ahujasid%2Fblender-mcp | Trendshift" width="250" height="55"/></a><br />
[![PyPI Downloads](https://static.pepy.tech/personalized-badge/blender-mcp?period=total&units=INTERNATIONAL_SYSTEM&left_color=BLACK&right_color=GREEN&left_text=downloads)](https://pepy.tech/projects/blender-mcp)


BlenderMCP connects Blender to Claude AI through the Model Context Protocol (MCP), allowing Claude to directly interact with and control Blender. This integration enables prompt assisted 3D modeling, scene creation, and manipulation.

**[Official website](https://blendermcp.org/)**

[Full tutorial](https://www.youtube.com/watch?v=lCyQ717DuzQ)

### Join the Community

Give feedback, get inspired, and build on top of the MCP: [Discord](https://discord.gg/SNqPn4TcKQ)

### Supporters

[CodeRabbit](https://www.coderabbit.ai/)

**All supporters:**

[Support this project](https://github.com/sponsors/ahujasid)

## Highlights

For the current version and changelog, see the [releases page](https://github.com/ahujasid/blender-mcp/releases).

- Added Hunyuan3D support
- View screenshots for Blender viewport to better understand the scene
- Search and download Sketchfab models
- Support for Poly Haven assets through their API
- Support to generate 3D models using Hyper3D Rodin
- Run Blender MCP on a remote host
- Telemetry for tools executed (completely anonymous)

### Installing a new version (existing users)
- For newcomers, you can go straight to Installation. For existing users, see the points below
- Download the latest addon.py file and replace the older one, then add it to Blender
- Delete the MCP server from Claude and add it back again, and you should be good to go!


## Features

- **Two-way communication**: Connect Claude AI to Blender through a socket-based server
- **Object manipulation**: Create, modify, and delete 3D objects in Blender
- **Material control**: Apply and modify materials and colors
- **Scene inspection**: Get detailed information about the current Blender scene
- **Code execution**: Run arbitrary Python code in Blender from Claude

## Components

The system consists of two main components:

1. **Blender Addon (`addon.py`)**: A Blender addon that creates a socket server within Blender to receive and execute commands
2. **MCP Server (`src/blender_mcp/server.py`)**: A Python server that implements the Model Context Protocol and connects to the Blender addon

## Installation


### Prerequisites

- Blender 3.0 or newer
- Python 3.10 or newer
- uv package manager: 

**If you're on Mac, please install uv as**
```bash
brew install uv
```
**On Windows**
```powershell
powershell -c "irm https://astral.sh/uv/install.ps1 | iex" 
```
and then add uv to the user path in Windows (you may need to restart Claude Desktop after):
```powershell
$localBin = "$env:USERPROFILE\.local\bin"
$userPath = [Environment]::GetEnvironmentVariable("Path", "User")
[Environment]::SetEnvironmentVariable("Path", "$userPath;$localBin", "User")
```

Otherwise installation instructions are on their website: [Install uv](https://docs.astral.sh/uv/getting-started/installation/)

**Linux:** install uv with `curl -LsSf https://astral.sh/uv/install.sh | sh` (it lands in `~/.local/bin`; open a new shell so it's on your PATH). On every OS, use uv's **official installer above — not `pip install uv`**, which may not create the `uvx` command and can hide uv inside an environment your client can't see.

**⚠️ Do not proceed before installing UV**

### Make your client find uvx

MCP clients started from a GUI (Claude Desktop, Cursor, VS Code from the Dock/Start menu) do **not** inherit your terminal's PATH, so a bare `"command": "uvx"` can fail with **`spawn uvx ENOENT`** even though `uvx` works in your terminal. If that happens:

- Find uvx's full path — `which uvx` (macOS/Linux) or `where uvx` (Windows) — and use it as `"command"`, e.g. `/opt/homebrew/bin/uvx` or `C:\Users\<you>\.local\bin\uvx.exe`.
- On Windows you can instead wrap it: `"command": "cmd", "args": ["/c", "uvx", "blender-mcp"]`.
- After any PATH or config change, **fully quit and relaunch** the client (Windows: quit from the system tray, not just the window; macOS: Cmd-Q).

### Pin the Python version (avoid conda / pyenv / version conflicts)

uv chooses which Python runs the server. On machines with conda (auto-activated base), pyenv, or asdf — or with a newer CPython release that some dependencies do not have wheels for yet — uv can grab an interpreter that makes installation fail. Pin Python 3.11 and prefer uv-managed interpreters to avoid using whatever is on your PATH:

```json
{
    "mcpServers": {
        "blender": {
            "command": "uvx",
            "args": ["--python", "3.11", "blender-mcp"],
            "env": { "UV_PYTHON_PREFERENCE": "only-managed" }
        }
    }
}
```

`--python 3.11` still satisfies this package's `requires-python >=3.10`, and `UV_PYTHON_PREFERENCE=only-managed` keeps uv from selecting conda, pyenv, asdf, or system Python first. (The repo's `.python-version` is only a hint for contributors and does **not** affect `uvx`.) If a previous failed attempt keeps replaying after a fix, clear the cache: `uv cache clean blender-mcp && uvx --refresh blender-mcp`.

### If uv won't work: install without uv

On locked-down machines you can skip uvx entirely with [`pipx`](https://pipx.pypa.io), then point your client at the installed command:

```bash
pipx install blender-mcp
pipx ensurepath          # then restart your shell / client
```

Use the resulting absolute path as `"command"` (find it with `which blender-mcp` / `where blender-mcp`) and omit `args`.

### Environment Variables

The following environment variables can be used to configure the Blender connection:

- `BLENDER_HOST`: Host address for Blender socket server (default: "localhost")
- `BLENDER_PORT`: Port number for Blender socket server (default: 9876)

Example:
```bash
export BLENDER_HOST='host.docker.internal'
export BLENDER_PORT=9876
```

### Claude for Desktop Integration

[Watch the setup instruction video](https://www.youtube.com/watch?v=neoK_WMq92g) (Assuming you have already installed uv)

Go to Claude > Settings > Developer > Edit Config > claude_desktop_config.json to include the following:

```json
{
    "mcpServers": {
        "blender": {
            "command": "uvx",
            "args": [
                "blender-mcp"
            ]
        }
    }
}
```
<details>
<summary>Claude Code</summary>

Use the Claude Code CLI to add the blender MCP server:

```bash
claude mcp add blender uvx blender-mcp
```
</details>

### Cursor integration

[![Install MCP Server](https://cursor.com/deeplink/mcp-install-dark.svg)](https://cursor.com/link/mcp%2Finstall?name=blender&config=eyJjb21tYW5kIjoidXZ4IGJsZW5kZXItbWNwIn0%3D)

For Mac users, go to Settings > MCP and paste the following 

- To use as a global server, use "add new global MCP server" button and paste
- To use as a project specific server, create `.cursor/mcp.json` in the root of the project and paste


```json
{
    "mcpServers": {
        "blender": {
            "command": "uvx",
            "args": [
                "blender-mcp"
            ]
        }
    }
}
```

For Windows users, go to Settings > MCP > Add Server, add a new server with the following settings:

```json
{
    "mcpServers": {
        "blender": {
            "command": "cmd",
            "args": [
                "/c",
                "uvx",
                "blender-mcp"
            ]
        }
    }
}
```

[Cursor setup video](https://www.youtube.com/watch?v=wgWsJshecac)

**⚠️ Only run one instance of the MCP server (either on Cursor or Claude Desktop), not both**

### Visual Studio Code Integration

_Prerequisites_: Make sure you have [Visual Studio Code](https://code.visualstudio.com/) installed before proceeding.

[![Install in VS Code](https://img.shields.io/badge/VS_Code-Install_blender--mcp_server-0098FF?style=flat-square&logo=visualstudiocode&logoColor=ffffff)](vscode:mcp/install?%7B%22name%22%3A%22blender-mcp%22%2C%22type%22%3A%22stdio%22%2C%22command%22%3A%22uvx%22%2C%22args%22%3A%5B%22blender-mcp%22%5D%7D)

### OpenCode integration

```json
{
  "mcp": {
    "blender-mcp": {
      "type": "local",
      "command": ["uvx", "blender-mcp"],
      "enabled": true,
      "environment": {
        "BLENDER_HOST": "localhost",
        "BLENDER_PORT": "9876"
      }   
    }
  }
}
```

### Installing the Blender Addon

1. Download the `addon.py` file from this repo
1. Open Blender
2. Go to Edit > Preferences > Add-ons
3. Click "Install..." and select the `addon.py` file
4. Enable the addon by checking the box next to "Interface: Blender MCP"


## Usage

### Starting the Connection
![BlenderMCP in the sidebar](assets/addon-instructions.png)

1. In Blender, go to the 3D View sidebar (press N if not visible)
2. Find the "BlenderMCP" tab
3. Turn on the Poly Haven checkbox if you want assets from their API (optional)
4. Click "Connect to Claude"
5. Make sure the MCP server is running in your terminal

### Using with Claude

Once the config file has been set on Claude, and the addon is running on Blender, you will see a hammer icon with tools for the Blender MCP.

![BlenderMCP in the sidebar](assets/hammer-icon.png)

#### Capabilities

- Get scene and object information 
- Create, delete and modify shapes
- Apply or create materials for objects
- Execute any Python code in Blender
- Download the right models, assets and HDRIs through [Poly Haven](https://polyhaven.com/)
- AI generated 3D models through [Hyper3D Rodin](https://hyper3d.ai/)


### Example Commands

Here are some examples of what you can ask Claude to do:

- "Create a low poly scene in a dungeon, with a dragon guarding a pot of gold" [Demo](https://www.youtube.com/watch?v=DqgKuLYUv00)
- "Create a beach vibe using HDRIs, textures, and models like rocks and vegetation from Poly Haven" [Demo](https://www.youtube.com/watch?v=I29rn92gkC4)
- Give a reference image, and create a Blender scene out of it [Demo](https://www.youtube.com/watch?v=FDRb03XPiRo)
- "Generate a 3D model of a garden gnome through Hyper3D"
- "Get information about the current scene, and make a threejs sketch from it" [Demo](https://www.youtube.com/watch?v=jxbNI5L7AH8)
- "Make this car red and metallic" 
- "Create a sphere and place it above the cube"
- "Make the lighting like a studio"
- "Point the camera at the scene, and make it isometric"

## Hyper3D integration

Hyper3D's free trial key allows you to generate a limited number of models per day. If the daily limit is reached, you can wait for the next day's reset or obtain your own key from hyper3d.ai and fal.ai.

## Persistent API credentials

BlenderMCP supports persistent credentials via Blender Add-on Preferences:

`Edit -> Preferences -> Add-ons -> Blender MCP`

You can store these values there so they survive Blender restarts:

- Sketchfab API Key
- Hyper3D API Key
- Hunyuan3D SecretId / SecretKey
- Hunyuan3D API URL

For headless setups or CI, credentials can also be injected by environment variables:

- `BLENDERMCP_SKETCHFAB_API_KEY`
- `BLENDERMCP_HYPER3D_API_KEY`
- `BLENDERMCP_HUNYUAN3D_SECRET_ID`
- `BLENDERMCP_HUNYUAN3D_SECRET_KEY`
- `BLENDERMCP_HUNYUAN3D_API_URL`

## Troubleshooting

- **Connection issues**: Make sure the Blender addon server is running, and the MCP server is configured on Claude, DO NOT run the uvx command in the terminal. Sometimes, the first command won't go through but after that it starts working.
- **Timeout errors**: Try simplifying your requests or breaking them into smaller steps
- **Poly Haven integration**: Claude is sometimes erratic with its behaviour
- **Have you tried turning it off and on again?**: If you're still having connection errors, try restarting both Claude and the Blender server


## Technical Details

### Communication Protocol

The system uses a simple JSON-based protocol over TCP sockets:

- **Commands** are sent as JSON objects with a `type` and optional `params`
- **Responses** are JSON objects with a `status` and `result` or `message`

## Limitations & Security Considerations

- The `execute_blender_code` tool allows running arbitrary Python code in Blender, which can be powerful but potentially dangerous. Use with caution in production environments. ALWAYS save your work before using it.
- Poly Haven requires downloading models, textures, and HDRI images. If you do not want to use it, please turn it off in the checkbox in Blender. 
- Complex operations might need to be broken down into smaller steps


#### Telemetry Control

BlenderMCP collects anonymous usage data to help improve the tool. You can control telemetry in two ways:

1. **In Blender**: Go to Edit > Preferences > Add-ons > Blender MCP and uncheck the telemetry consent checkbox
   - With consent (checked): Collects anonymized prompts, code snippets, and screenshots
   - Without consent (unchecked): Only collects minimal anonymous usage data (tool names, success/failure, duration)

2. **Environment Variable**: Completely disable all telemetry by running:
```bash
DISABLE_TELEMETRY=true uvx blender-mcp
```

Or add it to your MCP config:
```json
{
    "mcpServers": {
        "blender": {
            "command": "uvx",
            "args": ["blender-mcp"],
            "env": {
                "DISABLE_TELEMETRY": "true"
            }
        }
    }
}
```

All telemetry data is fully anonymized and used solely to improve BlenderMCP.

## Feedback

We are actively looking for feedback on Blender MCP. If you have thoughts, share them [here](https://bit.ly/blender-mcp-form).

If you have more detailed feedback, you can schedule a call with us [here](https://bit.ly/blender-mcp-call) - we will credit you in the project.


## Contributing

Contributions are welcome! Please feel free to submit a Pull Request.

## Disclaimer

This is a third-party integration and not made by Blender. Made by [Siddharth](https://x.com/sidahuj)