Good Morning Everyone.
I’m having a hard time figuring out why my light creates this “glittery” effect on the rock.
I’m on blender 4.0.2 and here is my render tab screenshot:
(Should I inclrease My max samples?)
Thankyou in advance
Hi, i think it’s coming from your noise texture/grass not the light.
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It’s not a sparkle of light, it’s like a noise pattern. 
We can also solve it by raising more samples.
Alternatively, you can disable GPU denoise and try Denoise filters in Composing.
Noise cancellation is not perfect. Complete removal is
Add…
Reduce the reflection value of shiny materials
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Hi,
Thankyou for your fast answer. I’ll take a look at my rock texture.
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Hi,
thanks for your fast answer.
I will try to raise the samples and disable noise.
also as @digitvisions and you said, I’ll take a look at materials and textures and then come back to you.
Thankyou very much
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I would say yes. 128 is a small number. Try these settings:
- Noise treshold: 0.03
The current number is very small and won’t do anything. The treshold is used to speed up the render by putting less effort on pixels when they become low enough on noise, a higher number=lower quality / more noise tolerated. 0.01 might only start to make a real difference after many hundreds of samples.
- Max samples: 512
This might seem like a lot compared with 128, but the higher treshold should accelerate the late samples quite a bit (and you can experiment with different tresholds to accelerate even more, see what value you can get away with).
- Min samples: 32
If you don’t pick a min samples, Cycles picks one for you based on a fraction of the max samples. I like to choose a number manually for better control. The min samples are useful so the treshold can better evaluate the noise of each pixel. If there aren’t enough min samples, it can make the noise glitchy and make it denoise poorly.
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I tried several approaches:
- First, I noticed that the “glittery” effect, as mentioned, was due to the normals of the grass texture. I gradually reduced the normal strength until I eventually set it to 0. However, this caused a loss of shadows at the front of the rock (see Picture 1 with normal strength set to 2, and Picture 2 with it set to 0).
0001.tif (2.2 MB)
0003.tif (2.2 MB)
- Next, I increased the max samples. I initially raised them to 512 and applied all the specifications suggested by @etn249. While this reduced the glitter, there was still a slight effect. So, I increased the max samples to 1024 and lowered the normal strength to 1, which fully resolved the issue.
In the end, the solution was a combination of both suggestions.
Thanks so much to @digitvisions, @oo_1942, and @etn249 for your help!
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There is still a very small amount of fine glitter. That is probably caused by a problem called “temporal coherence”, which is infamously difficult to fully solve.
When the camera moves, the subtle changes that pixels go through each frame mean that the denoiser will interpret fine details slightly different, causing flicker. This is especially visible in areas with high frequency details. It’s not a very big problem here, but I thought I would give you a solution anyway in case you ever have a problem with that.
The solution is the double resolution trick:
1- Set the render resolution to 200%.
2- Reduce the render quality until it takes the same amount of time to render as before (you can get away with this because the extra pixels increase the image’s quality).
3- Denoise and save the image still at 200%. Because of the extra resolution, the denoiser will perceive the fine details more clearly and preserve them better.
4- Reduce the images back to their intended resolution when you edit the video. Even after reduction, the image will remain more crisp and better denoised than it would have been.