It’s been a while since I attempted to render anything in Rhino, but the Raytraced view is lacking in performance, at least with Grasshopper when using the Custom Preview component.
I currently have Rhino 7 (7.5.21089.05002, 2021-03-30) installed.
The example scene looks like this in Ghosted mode:
In Rendered, everything turn brownish red? Maybe this is normal, but it would be nice if it would reflect the colors set in Grasshopper. Performance is fine.
This is Raytraced after a couple of seconds:
It’s so slow that it starts out with a black viewport.
Here’s the same scene after about a minute (no denoiser):
Quite bad result for the invested time.
And again after 5 minutes:
It’s simply too slow in my opinion! Sorry to say but Blender cycles works much quicker.
10 minutes for this …