I made a cube in Blender. The cube has BSDF Glass shader. When I render it there is a lot of noise and fireflies.

I tried everything: Change clamp, change light bounce, denoising, glossy filter, more samples... just everything. I don't know what to do now. When I removed the cube there wasn't noise. The light is point light and in the center of the cube. Blender 2.81 Beta, Cycles.


  • $\begingroup$ Have you tried turning on the denoiser? $\endgroup$
    – person132
    Oct 18, 2019 at 4:56
  • $\begingroup$ @person132 How to turning it on? $\endgroup$
    – Shak1234
    Oct 18, 2019 at 5:01
  • $\begingroup$ Did you uncheck caustics? $\endgroup$ Oct 18, 2019 at 10:40

1 Answer 1


Glass is something that causes a lot of noise in a cycles. While the proper solution is lots of samples, there are some options to get quicker acceptable results.

The first option added to 2.79 is Denoising

2.81 adds a new denoise composite node that uses Intels Open Image Denoise. CGCookie has a look and comparison.

There are also third party addons such as D-Noise.


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