Cinema4D MCP Server

Instructions

Execute a Python script in Cinema 4D's Python environment.

This is the most reliable tool for non-trivial operations — it gives full access
to the c4d API and avoids wrapper/schema mismatches that can affect other tools.

Args:
    script: Python code to execute in Cinema 4D. Has access to `c4d` and
        `c4d.modules.mograph` modules.

Important usage notes:
    - For animated/MoGraph data, always call doc.ExecutePasses() after SetTime():
        doc.SetTime(c4d.BaseTime(frame, fps))
        doc.ExecutePasses(None, True, True, True, c4d.BUILDFLAGS_NONE)
    - For MoGraph/effector data, iterate frames sequentially (0..N) rather than
      jumping directly to a later frame — sequential stepping produces more
      faithful results.
    - Security restrictions block certain keywords: import os, subprocess, exec(, eval(.
      Keep scripts within the c4d API surface.
    - For heavy operations (dense frame loops, complex MoGraph scenes), split work
      into multiple smaller scripts rather than one large monolith.
    - Use print() to return results — output is captured and returned.

Implementation Reference

• src/cinema4d_mcp/server.py:1069-1101 (handler)

  The handler implementation for the `execute_python_script` tool, which sends a script to Cinema 4D via a socket connection and formats the response.

  async def execute_python_script(script: str, ctx: Context) -> str:
      """
      Execute a Python script in Cinema 4D's Python environment.
  
      This is the most reliable tool for non-trivial operations — it gives full access
      to the c4d API and avoids wrapper/schema mismatches that can affect other tools.
  
      Args:
          script: Python code to execute in Cinema 4D. Has access to `c4d` and
              `c4d.modules.mograph` modules.
  
      Important usage notes:
          - For animated/MoGraph data, always call doc.ExecutePasses() after SetTime():
              doc.SetTime(c4d.BaseTime(frame, fps))
              doc.ExecutePasses(None, True, True, True, c4d.BUILDFLAGS_NONE)
          - For MoGraph/effector data, iterate frames sequentially (0..N) rather than
            jumping directly to a later frame — sequential stepping produces more
            faithful results.
          - Security restrictions block certain keywords: import os, subprocess, exec(, eval(.
            Keep scripts within the c4d API surface.
          - For heavy operations (dense frame loops, complex MoGraph scenes), split work
            into multiple smaller scripts rather than one large monolith.
          - Use print() to return results — output is captured and returned.
      """
      async with c4d_connection_context() as connection:
          if not connection.connected:
              return "❌ Not connected to Cinema 4D"
  
          # Send command to Cinema 4D
          response = send_to_c4d(
              connection, {"command": "execute_python", "script": script}
          )
          return format_c4d_response(response, "execute_python")