Hello guys. I just install Blender 3.0 and tested render. I tryed many settings but i cannot get the resault like in Blneder 2.93.
I dont want use denoising because iam using microdisplacement so i will lost the many details.
Do you know how should i set rendering?
Did you used some of the changes settings in https://wiki.blender.org/wiki/Reference/Release_Notes/3.0/Cycles ?
(for example: Branched path tracing was removed.)
This looks like it could be an issue with the noise treshold. In Blender 3.0, the render settings were renamed and moved so adaptive sampling is used by default and you may have to play a bit with the numbers to get the same result. With the new settings, you are expected to set max samples to something very high and control the quality level with the noise treshold.
Also, I have a workaround that can help keep more detail when denoising:
-Render and denoise at double resolution (you can reduce the samples so it doesn’t take longer).
-Save the image.
-Use an image editing software to reduce back to intended resolution.
But keep in mind that if you use adaptive subdivision with this trick, you may also need to reduce the quality of the subdivision, as the adaptive subdivision would generate more polygons with bigger screen resolution.
I’ve tried different settings of noise trashold, denoising but nothing works. Render is still noisy.
Just to be clear, the image you posted is an emissive sphere surrounded by volumetric fog, right (am I seeing correctly)?
I tried that kind of setup and the only way I managed to get something this noisy at 2000 samples is by turning off multiple importance on the emissive material (also, check the volume’s settings, in this case it should render best on equiangular).
are you adjusting the settings for viewport or render, or both?
Hi. Yes. Its just sphere with emmision and world shader is: Principles volume : Density 0.100 and Anisostropy -1.000.
Iam working on animation so i will need render around 12 600 frames in cycles. 
Render on 2000 samples sounds horrible
iam adjusting both
Well then, something else must be happening, because I tried these same settings and both versions of Blender gave me a similar amount of noise.
I would need to see the render settings to know for sure if there is some obvious problem. Could you possibly make a copy of the blend file, delete all objects/textures except the emissive sphere, the fog and the camera and upload the file here?
I looked at the file, and found it’s true that it renders differently between the versions of Blender. I think what’s happening is the cycles rewrite in Blender 3.0 changed the way volume is rendered. Your scene has the volume set to anisotropy of -1, which is a very rare use case that was probably not prioritised.
When testing, I have found that with your settings, your scene renders best when the volume is set to “distance”, unlike what I had found in earlier tests:
If I had to render this, I would maybe do it in 2 passes. I would first render the scene without the volume, with a black background. I would then do a second render with just the volume (all the objects placed in a holdout collection). This would allow denoising only the volume, since it doesn’t have as much detail that needs preserving. Then, you just composite the volume pass back on top with the “add” blending mode. However, this does change the lighting a bit on the solid objects, so it may not be suitable.
Another thing: have you tried the denoising in Blender 3.0 or 2.93? The Intel denoiser got updated compared with 2.93 and preserves detail better than before (especially if using the trick I wrote in a previous reply). This is just a hard scene to render and if you are going to render without denoising, you could need multiple thousands of samples.
Something else unrelated I have found is that a large part of the render time is due to your use of lots of procedural textures (each material has multiple noise textures). I don’t know if your textures need to be procedural, but if not, the scene would probably render way faster with image textures.
