Hi Lonnie,
HRDI is an option for a basic environment in Rhino for Mac.
Here is a similar tread on Rendering on Rhino for Mac.
See this video that walks you through the Mac Materials library and setting the environment to a HDRI. I think it will help you.
You can download HDRI’s from Food4Rhino.
You can also download the standard Rhino for Windows HDRi’s.
These should install with Rhino for Mac IMO. (Bug Item: MR-3080)
Let us know.
Sincerely,
Mary Ann Fugier