Smoke simulation tricks

by - 2012/04/19 23 Comments Random

I’ve been doing some tests with smoke simulation lately, and I met an interesting case I’d like to share. After doing some simple smoke emissions, I tried to get smoke trails. For unknown reasons a flickering was ruining the shading, no matter which resolution I was baking the simulation.
I showed the file to Daniel Genrich (Genscher) and Miika Hämäläinen (MiikaH) who provided a fix and a simple explanation.

The flow object Absolute Density had to be turned off and the Density parameter had to be turned down from 1 to 0.3: this prevented emitted particles to overlap in space and generate part of the flickering effect.

For the Domain object, the “color” texture had to be tweaked so that in the Voxel Data panel the source appeared to be Heat instead of Velocity.

This changed massively the quality of the simulation, which then I baked at high resolution. You can compare the results in the following video (there were some caching issues, so the final part of the sim is not complete), and you can also download the files if you are interested in the settings.

  1. Matt says:

    Youtube link shows as private for me.

  2. Matt says:

    Nevermind, now it works (don’t know why it didn’t 10 seconds ago).

  3. Christoph Pöhler aka Dracio says:

    fine job looks like the final Meteor :D
    and Thanks for sharinge
    I try to understand the fire in blender and it is not so easy

  4. JiBZ says:

    very nice result!

  5. lucky says:

    The flickered one looks better (high smoke density is more convincing), I hope you’ll find a fix!

  6. Ace Dragon says:

    Personally, I would love to see the functionality needed to render this puppy in Cycles if doing such a thing is possible, I would imaging the simulation would render in a more realistic fashion as a result due to the smoke then being able to receive environmental and indirect light.

    There was a youtube video that showed GPU smoke rendering at a rather impressive speed for path-traced volumetrics, so I hope the current work from storm_st will at least give Brecht a starting point for the volumetric implementation.

  7. Martin says:

    I was also surprised to see that the flickering one looks much more realistic than the second one. would consider to incorporate some noise into particle color animation

  8. Bao2 says:

    Are you guys using Lamps for the integration of CG objects with footage? Or are you using Emit Meshes?

    With emit meshes I found it gives much better result. Is explained here:

  9. Hubberthus says:

    I also think that the flickering one is more realistic, it looks really cool that the flame is inside the smoke.
    On the second one the gradient from yellow to black is too smooth.
    I hope that the flickering can be fixed!

  10. Daniel says:

    Actually I think the flickering effect is quite good, if a little too much in the video. It gives the impression of something on fire in the centre. Maybe you could try introdcing a subtle flickering back into the smoke and see how it looks?

  11. 3pointedit says:

    Not only the flicker but the dispersal of heat (light) in a random manner through the smoke. Billowing smoke seems to have different densities(?) or fluctuations of heat moving through. So the newer version is a bit to homogenus.

  12. comeinandburn says:

    It would be great if Blender would get some nice fake smoke that would render way faster… like a sprite/billboard setup (presets) like Trapcode Particular in After Effects. This would be sufficient for probably 90% of smoke simulations. Real 3D smoke is only really necessary if you plan on passing through it.

  13. Psy-Fi says:

    From my own experience with the smoke simulation, I think the most irritating part is that to make an interesting flame you need to constrain the colour ramp to a very narrow range of the heat values, making this a bit difficult to fine tune. Impressive results though :)

  14. Alexander M says:

    I really liked the flickering one! you should add some random flickering to the fixed version too :D

  15. pixelnate says:

    All of the people saying the first one looked better/more realistic: you’re on crack. The elements/fragments of burning whatever coming off of the fireball would burn from yellow to red to black as the turned to char. They wouldn’t immediately turn to char the way that the first example shows. A burning fireball leaves a trail of smoke as it burns.

    Great job, Francesco.

  16. I would love to look at your example files, but your link leads to a 404. Could you fix the link so I can study your work?

  17. Gibran says:

    Hi francesco, I’ve been experimenting with smoke and been getting near to this fireball thing… but I fail by setting the fire and still I don’t have an idea of how to add it correctly I’d be thankful if you could share with me your file ! Can you please do it? since the link you shared is broken… thanks

  18. chrisstooph says:

    Does anybody have a blend. file for smoketrail example? Unfortunately this above doesn’t work.

    BTW nice result!

  19. Axel says:

    The flickering is occuring due to the adaptive domain. The domain’s constant change in size affects the render in such a way that it flickers. To prevent this you can uncheck adaptive domain in your domain settings. This will increase the baking time. If you dont want to wait forever watch this:

  20. kil says:

    Any chance to get somewhere?

    • Wender Silva says:

      Link “” off… a want this file please…