I've released a free Python plugin for Cinema 4D: Send to Auddomate Render. It adds Extensions → Send to Auddomate Render, which exports the open scene as glTF and hands it to Auddomate Render, a free spectral path tracer that runs in the browser (WebGPU). The scene arrives already loaded, with its cameras, materials and animation.

A few details that might interest people here:

• It exports a clone of the document, so the open scene is never modified, and it restores your own glTF exporter settings afterwards.
• Node materials that the glTF exporter can't write (Redshift and similar) are swapped for standard-material stand-ins in their average color, keeping their names, so nothing arrives plain white. The renderer lists which ones to finish.
• Standard-material metals are detected from the reflectance layers' conductor Fresnel and patched into the GLB, so only real metals come across as metal.
• The hand-off happens over a short-lived loopback server on 127.0.0.1, so nothing is uploaded. A copy of every sent scene is also saved in Documents/Auddomate Render.

Free for personal and commercial use. Tested on Cinema 4D 2024 (macOS); it should work on 2024 and later on Windows too, and reports from other versions are very welcome.

Download and install steps: https://auddomate.com/docs/cinema-4d/

Thanks to the SDK team and this forum: the plugin ID page and a few old threads here made this much easier.