Cinema4D MCP Server

Cinema4D MCP — Model Context Protocol (MCP) Server

Cinema4D MCP Server connects Cinema 4D to Claude, enabling prompt-assisted 3D manipulation.

Table of Contents

• Components
• Prerequisites
• Installation
• Setup
• Usage
• Development
• Troubleshooting & Debugging
• File Structure
• Tool Commands

Components

1. C4D Plugin: A socket server that listens for commands from the MCP server and executes them in the Cinema 4D environment.
2. MCP Server: A Python server that implements the MCP protocol and provides tools for Cinema 4D integration.

Prerequisites

• Cinema 4D (R2024+ recommended)
• Python 3.10 or higher (for the MCP Server component)

Installation

To install the project, follow these steps:

Clone the Repository

Install the MCP Server Package

Make the Wrapper Script Executable

Setup

Cinema 4D Plugin Setup

To set up the Cinema 4D plugin, follow these steps:

1. Copy the Plugin File: Copy the c4d_plugin/mcp_server_plugin.pyp file to Cinema 4D's plugin folder. The path varies depending on your operating system:
   • macOS: /Users/USERNAME/Library/Preferences/Maxon/Maxon Cinema 4D/plugins/
   • Windows: C:\Users\USERNAME\AppData\Roaming\Maxon\Maxon Cinema 4D\plugins\
2. Start the Socket Server:
   • Open Cinema 4D.
   • Go to Extensions > Socket Server Plugin
   • You should see a Socket Server Control dialog window. Click Start Server.

Claude Desktop Configuration

To configure Claude Desktop, you need to modify its configuration file:

1. Open the Configuration File:
   • macOS: ~/Library/Application Support/Claude/claude_desktop_config.json
   • Windows: %APPDATA%\Claude\claude_desktop_config.json
   • Alternatively, use the Settings menu in Claude Desktop (Settings > Developer > Edit Config).
2. Add MCP Server Configuration: For development/unpublished server, add the following configuration:
   "mcpServers": { "cinema4d": { "command": "python3", "args": ["/Users/username/cinema4d-mcp/main.py"] } }
3. Restart Claude Desktop after updating the configuration file.

Usage

1. Ensure the Cinema 4D Socket Server is running.
2. Open Claude Desktop and look for the hammer icon 🔨 in the input box, indicating MCP tools are available.
3. Use the available Tool Commands to interact with Cinema 4D through Claude.

Testing

Command Line Testing

To test the Cinema 4D socket server directly from the command line:

You should see output confirming the server's successful start and connection to Cinema 4D.

Testing with MCP Test Harness

The repository includes a simple test harness for running predefined command sequences:

1. Test Command File (tests/mcp_test_harness.jsonl): Contains a sequence of commands in JSONL format that can be executed in order. Each line represents a single MCP command with its parameters.
2. GUI Test Runner (tests/mcp_test_harness_gui.py): A simple Tkinter GUI for running the test commands:
   python tests/mcp_test_harness_gui.py
   The GUI allows you to:
   • Select a JSONL test file
   • Run the commands in sequence
   • View the responses from Cinema 4D

This test harness is particularly useful for:

• Rapidly testing new commands
• Verifying plugin functionality after updates
• Recreating complex scenes for debugging
• Testing compatibility across different Cinema 4D versions

Troubleshooting & Debugging

1. Check the log files:
   tail -f ~/Library/Logs/Claude/mcp*.log
2. Verify Cinema 4D shows connections in its console after you open Claude Desktop.
3. Test the wrapper script directly:
   cinema4d-mcp-wrapper
4. If there are errors finding the mcp module, install it system-wide:
   pip install mcp
5. For advanced debugging, use the MCP Inspector:
   npx @modelcontextprotocol/inspector uv --directory /Users/username/cinema4d-mcp run cinema4d-mcp

Project File Structure

Tool Commands

General Scene & Execution

• get_scene_info: Get summary info about the active Cinema 4D scene. ✅
• list_objects: List all scene objects (with hierarchy). ✅
• group_objects: Group selected objects under a new null. ✅
• execute_python: Execute custom Python code inside Cinema 4D. ✅
• save_scene: Save the current Cinema 4D project to disk. ✅
• load_scene: Load a .c4d file into the scene. ✅
• set_keyframe: Set a keyframe on an objects property (position, rotation, etc.). ✅

Object Creation & Modification

• add_primitive: Add a primitive (cube, sphere, cone, etc.) to the scene. ✅
• modify_object: Modify transform or attributes of an existing object. ✅
• create_abstract_shape: Create an organic, non-standard abstract form. ✅

Cameras & Animation

• create_camera: Add a new camera to the scene. ✅
• animate_camera: Animate a camera along a path (linear or spline-based). ✅

Lighting & Materials

• create_light: Add a light (omni, spot, etc.) to the scene. ✅
• create_material: Create a standard Cinema 4D material. ✅
• apply_material: Apply a material to a target object. ✅
• apply_shader: Generate and apply a stylized or procedural shader. ✅

Redshift Support

• validate_redshift_materials: Check Redshift material setup and connections. ✅ ⚠️ (Redshift materials not fully implemented)

MoGraph & Fields

• create_mograph_cloner: Add a MoGraph Cloner (linear, radial, grid, etc.). ✅
• add_effector: Add a MoGraph Effector (Random, Plain, etc.). ✅
• apply_mograph_fields: Add and link a MoGraph Field to objects. ✅

Dynamics & Physics

• create_soft_body: Add a Soft Body tag to an object. ✅
• apply_dynamics: Apply Rigid or Soft Body physics. ✅

Rendering & Preview

• render_frame: Render a frame and save it to disk (file-based output only). ⚠️ (Works, but fails on large resolutions due to MemoryError: Bitmap Init failed. This is a resource limitation.)
• render_preview: Render a quick preview and return base64 image (for AI). ✅
• snapshot_scene: Capture a snapshot of the scene (objects + preview image). ✅

Compatibility Plan & Roadmap

Compatibility Goals

• Short Term: Ensure compatibility with C4D 2023.1+ (Python 3.9 and 3.10)
• Mid Term: Add conditional handling for missing MoGraph and Field APIs
• Long Term: Consider optional legacy plugin module for R23–S26 support if demand arises

Recent Fixes

• Context Awareness: Implemented robust object tracking using GUIDs. Commands creating objects return context (guid, actual_name, etc.). Subsequent commands correctly use GUIDs passed by the test harness/server to find objects reliably.
• Object Finding: Reworked find_object_by_name to correctly handle GUIDs (numeric string format), fixed recursion errors, and improved reliability when doc.SearchObject fails.
• GUID Detection: Command handlers (apply_material, create_mograph_cloner, add_effector, apply_mograph_fields, set_keyframe, group_objects) now correctly detect if identifiers passed in various parameters (object_name, target, target_name, list items) are GUIDs and search accordingly.
• create_mograph_cloner: Fixed AttributeError for missing MoGraph parameters (like MG_LINEAR_PERSTEP) by using getattr fallbacks. Fixed logic bug where the found object wasn't correctly passed for cloning.
• Rendering: Fixed TypeError in render_frame related to doc.ExecutePasses. snapshot_scene now correctly uses the working base64 render logic. Large render_frame still faces memory limits.
• Registration: Fixed AttributeError for c4d.NilGuid.