Hi,
In V7, the “raytracing” mode default ray number is too high for realtime display in the viewport.
I know it can probably be tweaked in the settings, and I will do that once Rhino unfreeze in probably 10 minutes when it finishes computing the 1000-rays raytracing render I didn’t ask for…
For a comparison, in Blender the default rays number for realtime display in the viewport is 32 and 128 when you formally render a high def image with the render function :