Material Transparency Problem w/ Sun Env

R6 SR20

This Problem is pretty self-explanatory. Some materials are erroneously transparent (maybe only to shadows?) in “Rendered Viewport” mode. (Rhino Render.)
I can recreate it by simple Ticking the Sun to “on”. Which is why this seems buggy.

There is not any actual transparency on the Walnut Wood material.
BUT ! I can fix, and Make solid the Walnut material problem by sliding the Walnut Material transparency up by any amount from zero and back… and then the Buggy Transparency disapears.

I don’t know enough about Rhino’s overhauled Default viewport renderer to have an inkling why this would be.

Has any one else seen this and shook their fist ?

Hello - I believe that is reported here:

and fixed in 6.22 is my guess, as a public release. Does a full render get it right?