What happened to Scrambling Distance? It´s been used in Theory and it will help speed up rendering


This is ridiculous! It’s not more harmful than simplify AO or clamping.


Totally agree with you


Juan I just checked and realized those tests were done with GPU+CPU enabled, I’ll do some more renders tonight with GPU only and post my results as well. I’ll also try with an interior scene to see if there’s more visible errors as @AdamPreisler mentioned.



Thanks! If you can do both, GPU only and CPU only :slight_smile:

And do some with 200 samples instead of 500 too, to compare noise levels at low sampling (at scrambling 0.02 may look bad with just 100 or 200 samples)



Sure I’ll do the tests with less samples :+1:


I tried yesterday the win compilation from @JuanGea with the BMW test and even upscaling to UHD resolution with half samples I rendered almost same quality using denoiser at .2, making usable even with 4 or 5 samples @32 bounces!

The Scrambling Distance and the Dithered Sobol are the two best performance features imho I’ve seen in Cycles in a while. This definitely helps to get cleaner renders in less time, making cycles usable with a decent frame rate through RTX like eevee will works in low-end desktops.

OFFTOPIC: Also the Optix Denoiser or DeepBlender AI Denoiser are a important feature to work with the Dithered Sobol and Scrambling Distance.

Im a bit busy this weekend but maybe I’ll do some test to publish here too.

i7 5700HQ - 16Gb RAM - GTX 960M - Win10 / Ubuntu
i7 950 - 24Gb RAM - GTX 1060 - Win10


i’m doing some test with the SD only, here’s some gifs

Setting :
256 samples
full GI
Other are stock

256 samples
Limited GI
Other are stock

just to tell my thoughts, as other said we should have this feature in the experimental cycles and let decide the artist if he wants accuracy or speed, as like this feature the denoiser also create artifacts and it is in master, the simplefy AO also make the render biased and it is in master so, and to respond to brecht not all our scene have volume or hair, so i hope we can get this in master, same thoughts about the dithered sobol, those 2 feature combined with simplify are really great

i’m going to test an animated smoke sim next

EDIT : cuda gots an error when i try to render volumetric


It´s not a volume related crash, as far as I can see it´s a smoke related crash, but it could be related to an old bug or something like that, because it´s an old build and it crash even without using scramble and/or DSobol.

The build is from 13th of August :stuck_out_tongue: pretty old and in a moment of continuous development that could have had some kind of smoke related bug :slight_smile:

I´m also testing it.



For some reason I haven’t been able to do anything with the dithered sobol build again, everytime I try to do a test Blender crashes and freezes my pc. I haven’t changed anything since the last test I did, so can’t really tell what it is… :frowning:


That´s weird, try deleting your blender preferences, or try disabling all the addons, going back to factory defaults or something, it´s working fine for me here.



i also vote for includeing all those stuff to blender. scrambling adaptive etc etc. Blender in the end is used by proffesionl artist that know what you are doing. and those 2 features sometimes made jobs possible or not possible to deliver on time. When whole comunity want’s a feature but developer says no because begginer will not be able to use it. i think that is not right. just put it to experimental till u make it. working right. simple as that. It was so long time ago when it was done. that till that time it would probably be all sorted out.

funny thing is that u guys included denoiser that does have flickering and other problems… but with this u are like nope.


Tried everything you said, deleted the whole thing and downloaded again and even put it on another drive, just to keep it separated from the default install, but with no luck… since yesterday I can’t use this build anymore.


EDIT: @JulianPerez I prefer to avoid hijacking this topic with this, we can talk over Blender.chat to try to help you.

That is weird… do you have a different computer to try it?


After digging a bit it seems that in that build textures plugged into volumes are broken.

Also after reviewing times of some of the tests there is a result with a time that is higer with Scramble Distance enabled, that is a bit weird because no matter what, SD should make the render faster, even when it could give wrong results.

I think LordOdin can give a more experienced opinion on this, since they use it almost always.



acctualy i remember the D808 case. i also readed it again. u said back in that time that one of the reasons why u droped it it was because it would destroy back comp. but since 2.8 is doing this… maybe there is new aproach that we can acctualy implement adaptive sampling and scrambling distance. i mean. they did the job… even in test era and that was long time ago… done on knee.


Then it´s the perfect time to include it.

On the other hand, I shifted from the build with SD and DS to an stardard master daily build version, and nothing broke, the only thing was that instead of having Dithered Sobol it was configured as Correlated Multijitter, but everything was working normally.

I hope those two features can be included in master as experimental.


The build will crash with textures being plugged in to volumes. Its unrelated to scrambling or dithered sampling though.

You should never ever get slower results with scrambling unless you are using a CPU with adaptive clocks or you are doing stuff in the background which you shouldn’t be doing when trying to benchmark things

Also IDK adaptive sampling definitely wasn’t finished and would take a lot of work on Lukas part to get it implemented. But scrambling and dithered can simply be committed today and work in master(2.79lol)

Im sure with the api changed there would need to be some gui adjustments for 2.8


I want to share with alll of you a live streaming that I did reviewing the optix denoiser AND these two features, the interesting part for the thread is the part where I go over the features, I can´t find anything hurting Blender or any user, and it works flawlessly.

The Scramble Distance and the Dithered Sobol part starts in minute 25 more or less.

I hope it´s ok that I put this here, I sincerely think that it is related to all this.



This video does a really good job showing all the good parts and bad parts of scrambling. It took @JuanGea less than 3 days to fully understand scrambling and make this in depth video explaining how it should be used… 3 Days! If an artist cant figure this out they probably shouldn’t be trying to use blender in the first place.

Anyone doubting the importance of these features just watch the video. (He even shows you how to break your renders without using scrambling haha)


Something that wouldn’t be entirely doable without the help of scrambling + dithered because it would just take too long. Also its helped a little with the optix denoiser