I'm trying to figure out the solution for this problem.

This is a screenshot of the render of toruses with default glass shader in absolutely whire environment.

enter image description here

As you can see there are some black artifacts (looks like reflections) on the glass.

Also notice that the number of the transmission bounces, global bounces, and translucent bounces are pretty high. There is also no clamping.

What is the problem? And how to solve it? Any ideas?

Blender 3.1 For this experiment I used CPU render.

  • 4
    $\begingroup$ I would suggest you increase the Max Bounces for Glossy. $\endgroup$ Apr 4, 2022 at 13:09
  • $\begingroup$ @moonboots The screenshot shows the Light Paths settings... this is Cycles. $\endgroup$ Apr 4, 2022 at 13:11
  • $\begingroup$ oops ok sorry.... $\endgroup$
    – moonboots
    Apr 4, 2022 at 13:17
  • 1
    $\begingroup$ Hi :). There are many possible reasons. Search this site, it could be anything from glossy bounces, to HDRI ;) $\endgroup$ Apr 4, 2022 at 13:25
  • $\begingroup$ You can also share part of the file pasteall.org/blend ;) $\endgroup$ Apr 4, 2022 at 13:26

1 Answer 1


It was glossy bounces. Thanks!


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