Arnold for Cinema 4D (or C4DtoA) provides a bridge to the Arnold renderer from within the standard Cinema 4D interface.

Only C4D R25

The plugin is fully functional (MG)

Arnold for Cinema 4D (or C4DtoA) provides a bridge to the Arnold renderer from within the standard Cinema 4D interface.

Features

• Seamless integration with C4D: objects (instances, cloners, deformers, generators), MoGraph geometry, hair and splines.
• Support for both native particles and Thinking Particles.
• The fastest interactive rendering (IPR) of all Arnold plugins, allows parameter changes to be rapidly previewed without interrupting your work.
• Arnold Shading Network Editor, a node-based material editor.
• A comprehensive list of shaders and utilities, including vertex maps and per-face materials.
• Volume rendering with OpenVDB.
• Deferred, render time generation of geometry with the Arnold procedural node.
• Native linear workflow.
• Team Render, including single-frame distributed rendering.
• Support for third party plugins like X-Particles and Turbulence FD.

http://www.arnoldrenderer.com/arnold/arnold-for-cinema-4d/