Material basics for Rhino 6 (11 min)
This video is produced by Vanessa Stegg, a co-worker of Rhino Robert McNeel & Associates and member of Rhino Tutorials.
Viewport “Render” mode
The Render Mode is very well suited for fast visualizations in the design process.
Rendering in “Raytraced” mode
For raytraced render mode: you need a fast graphic card (GPU), ideally Nvidia graphic card with a lot of CUDA.
If you have performance issues try a smaller viewport resolution/size.
Render image-files by “Viewport/capture/capture to file”.
For more issues with raytrace render: link