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Getting rid of smoke blockiness

May-10-2013    12 Comments

Burning SuzanneI was recently investigating how to reduce that blockiness you get around smoke emitters. I did several tests with it and was so amazed about the results that it frankly makes me feel stupid for not realizing there was something wrong earlier.

Previously high resolution flow voxels were generated based on the low resolution ones. So if you had 32 simulation base resolution and 4 division high resolution, it still used smoke flow generated from those 32 resolution voxels. Now I introduced a new sampling method called "Full Sample" that generates full resolution flow for for high resolution domain as well.

You can enable "Full Sample" in smoke high resolution panel. That menu also includes old "Nearest" and "Linear" interpolation settings for smoke flow in order to keep old files compatible. Full sample is default in new simulations though.

There was also a bug that partly disabled smooth effect from my older smoke patch from couple of years back.

Here is a comparison between old and new high resolution smoke:

Left suzanne is the low resolution version (32 res). Then the old (4 division) high resolution flow. Last one is the new "full sample" version using otherwise same settings.

Another comparison with a complex mesh flow:

Again, left is the old 32 res 4 high division simulation. Right image is same setup with full sample flow.

One problem especially with fire simulations has been that the fluid motion usually looks good with fairly low resolutions. However it has been necessary to increase the resolution anyway, in order to get rid of those blocks. Not anymore. It's also much easier to create thinner layer of smoke around the emitter. Not to mention higher detail when using textures as flow masks. :)

I made couple of new fire demos inspired by the possibilities of block-free smoke flows:

Here are the original .blend files for you to play with:
Burning Suzanne (64 base, 4 div high): burning_suzanne.blend
Burning Plane v2 (48 base, 3 div high): burning_plane_turbulent.blend

The new full sample flow type is available in Blender trunk builds of revision 56665 and higher (or the upcoming 2.68 release).

Posted by MiikaH at 16:18

Category:Blender, Development
Tags: Blender, Smoke, Fire

(Comments, questions or discussion about this post.)

May-10-2013 17:05
Miikah, I ... love ... you ;) You just amped up all of my smoke / fire simulations... I was biting in my desk as I saw all those blocks around my emitters - now it's perfectly fine! Thanks so much!
May-13-2013 12:11
your are awesome man thx a lot
mike kelly
May-23-2013 23:39
just got 2.67a another great release. one question though,the new full sample feature, as far as i can tell its not there.do i have to enable something in preferences, and the other new feature isnt there either.if i have to get a build from this site for those features,could someone give me a heads up.thanks in advance for any help
Google Chrome
May-24-2013 07:02
Yes! I am glad to see Blender’s smoke simulator getting some more improvements!
May-24-2013 08:53
@mike kelly

2.67a is a bug fix release, so it doesn't have any new features. Full sample smoke will be included in 2.68 release.
mike kelly
May-24-2013 16:50
ok thank you so much for the reply. cant wait to see it in trunk. thanks again.
mike kelly
May-24-2013 17:29
at the risk of being annoying, and just so i know for sure,are these new features for smoke sim's available in your builds.i have r96945.i know it says one or the other up top.if i gotta wait,well you know. thanks again.happy blending
May-24-2013 17:32
@mike kelly

Yes, these new features are available in latest trunk builds.
May-25-2013 13:13
This is really awesome! :) Now with these changes Blender's Smoke system is becoming very usable!

P.S. MiikaH, a little request:

can you make the cache for Dynamic Paint saveable within .blend (as it happens with particle systems and other caches)? It's very important for future usage with render farms like RenderWeb because they don't support (and probably will not) outer caches. I've noticed this lack when I tried to render my animation there. It was rendered but partially - without grass' animation that is using Dynamic Paint feature.
Kevin Tee
Jun-14-2013 04:20
Does this render faster? Because smoke render very slow on my i7 3770 at high resolution(128).
Jul-05-2013 19:45
Hello Mika, you guys are also planning add sss node to GPU? Thanks!
Aug-22-2013 14:13
Hello Mika,
I was trying to use v2.68 to get the fire flow effect, but its just not working!!! i m fed up....need ur help.. i t would be so nice of u if u could repond me at anish000kumar@gmail.com...thanks in advance

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By: Miika HämäläinenLast update: Nov-07-2014 14:18MiikaHweb | 2003-2021