Posted by: Jeff | 2011/03/06

FumeFX – Crawling Smoke

Largely inspired by the work done in the movie 2012, I did some tests on how some FumeFX (1.x) parameters would affect a crawling smoke simulation.

Scene Setup:

  • I’m using a Gravity Vector object pointing towards the side, thus creating the effect of crawling smoke.
  • Grid Size is on average @ 300x300x300.
  • Simple Src with a disabled Smoke Channel.
  • “Fuel Creates Smoke” checked. (This was renamed to “Fire Creates Smoke” on newer versions 2.x?)

The Comparisons:

1. Smoke – Density | Diffusion
– High Diffusion for softer/fluffy smoke.
– High Density seems to have affected the smoke movement.

2. Smoke – Density | Gravity
– High Density also seems to prevent the smoke to expand.

3. Grid Spacing & System Scale*
– To see smoke details on a small SystemScale setup, use smaller Grid Spacing.

4. Grid Spacing & Advection Stride
– The Grid Spacing doesn’t seem to have a significant effect on Advection Stride. (Also see #8)

5. Grid Spacing & Time Scale
– It is generally a good practice to have higher Time Scale values in order to bring out more details.

6. Grid Spacing & Vorticity
– High Vorticity will add more details.
– Low Vorticity, smoother smoke.

7. Advection Stride & Vorticity
– In the case of this scene, a Vorticity setting of 1.0 is not recommendable as you loose a lot of detail.

8. Time Scale & Advection Stride
– The Time Scale also doesn’t have a significant effect on Advection Stride. (See #4)

9. Time Scale & Vorticity
– Time Scale helps to impose the sense of scale.

* The System Scale parameter is only accessible through MaxScript. Here’s a quote from Kresimir Tkalcec from the Afterworks forums:

“Some params that are visible from MXS and not documented are not officially supported, and/or they’re used internally.”

To set the parameter say to a value of 0.5, simply select your FumeFX Grid Object and enter this to the Listener:

$.systemScale = 0.5

Test Simulations:

Crawl Smoke Side

Crawl Smoke Alley

Crawl Smoke City

Crawl Smoke Wispy

Crawl Smoke Front

Additional Video:

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  1. oh my god,

    your information is awesome!

    Thanks for share!

  2. Very cool of you to share all of this research.
    This is very helpful and greatly appreciated.
    Could you supply more info like the grid size and sources used?

  3. You’ve gone and done it again!

    Great stuff

    Good to see you Jeff 🙂

  4. Cool rnd and summary! In 2.1 things get changed a bit though, and some nice things could be achieved by making smoke itself buoyant, with low temperature.

  5. Thanks for the additional info.

  6. wow, this is really great info thanks Jeff~

  7. you’re welcome guys 🙂 I hope you find these useful 🙂

  8. awesome blog you have bro!! congratz!!

  9. great one Jeff !

  10. thanks for sharing! this is awesome!!

  11. great effort for FXcian..

  12. Giant research!!! thanks

  13. Very useful study… really appreciate it!!! Thanks

  14. […] Долго мучался,перетестил все методы и способы,очень помогло для понимания происходящего исследование вот этого человека […]

  15. Thanks for sharing..How you set Vorticy more then 1 perhap 1.2 or 1.5 in the Maxscript listener?

  16. All of these rNd’s are kewl man… 🙂


  17. Just curious – did you bother keeping everything to a real world size in terms of your grid and emitter or just use system scale for your sizes?

    • nope, didn’t bother with the scaling.. most of the time, I found that you only need to play around the motion and look/detail of your smoke in order to get the sense of scale just about right. I hope that helps. 🙂

  18. wow thats so incredible usefull !!!!!!!!!!!!! thanks a lot !!!

    • thanks matthias!
      btw, im a big fan of your particle tests on youtube! 😀

  19. This one is amazing!……Thanks a lot Jeff 🙂

  20. muy bueno sir..

  21. […] […]

  22. Thanks Jeff, an essential reference for anyone using Fume FX. Appreciate your hard work.

  23. Hmm, I tried to recreate these and failed. There is no “Fuel Creates Smoke” button, there’s a “Fire creates smoke” but I have a feeling you are not using fire?
    Can you please be more (very) specific about how you created these setups, or post or mail me one of these scenes?

  24. I ԝas ablе to find gοod advice frօm yoսr content.

  25. youre excellent. I cannot thank you enough.

  26. also where is this Fuel Creates Smoke at? I cant find it in Maya.

    • In the latest version, I suppose it was renamed to:
      Fire Creates Smoke:
      Found under the sim > Fuel rollout in 3dsmax (Unfortunately, I don’t have access to the Maya version of Fumefx)

  27. I am searching “smoke density” in Fume but just can’t find it. Can you guys please help me out? Which option is it? Is it in the old versions of Fume? I am using 3.5.

    • Density is equals to the amount of smoke. It can come from the Source emitter’s Smoke Amount, and/or under the Fuel settings > (Fire Creates Smoke) Smoke Density.

      And as a related parameter upon rendering, you could also try increasing the Smoke Opacity.

      • thank you so much man, I really appreciate. I was going for the same idea/answer.

  28. Nice..
    How do you restrict the motion of the smoke in upward direction?

    • Are you referring to the constant sidewards motion?
      I was using an old technique I learned from cgtalk.
      You use a Gravity Vector Helper (that comes with FumeFX) to rotate the gravity to the direction you want, in this case sidewards.
      The drawback is you would essentially sacrifice having a natural downwards gravitational pull on your sim.

  29. Thank you very much. Im working on a project and found it very difficult to achieve the results i wanted for my smoke effects. Ill study all your videos thoroughly. I hope to acheive the quick expanding fluid explosion effect; these observations will help alot 🙂

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