I am trying to fill the mesh shown below with thick smoke. To this end, I placed an emitter UV sphere inside the mesh and set the mesh to fluid effector. The smoke is now contained in the mesh. Now I would like it to fill the mesh but I cant seem to figure out how to best do this. I tried a wind forcefield to blow the smoke further into the mesh which works to some extent, but the smoke gets thin and invisible. What would be a good way to fill the mesh starting from the emitter UV sphere? Any help is much appreciated! Edit: I am aiming at an animation of the smoke filling the mesh from the UV sphere as a starting point. Thank you.enter image description here

  • $\begingroup$ The best setting? Fake it with some Volumetric shader ... :) Smoke is really bad option in filling obtacles, even you increase density final shape would be cuby (if there wasnt major improvement in smoke sim). $\endgroup$
    – vklidu
    Commented Mar 19, 2022 at 18:51
  • $\begingroup$ Thank you for you comment. I am aiming at an animation though, so I am not sure how this would work. I have edited my question in this regard. $\endgroup$
    – Iam Hidari
    Commented Mar 19, 2022 at 18:56
  • $\begingroup$ It was clear to me (you aim to anim) :) Do you have a reference how final anim should looks like? If not shader ... so probably some particle system or fluid sym with volumetric could be an experimental way here ... $\endgroup$
    – vklidu
    Commented Mar 19, 2022 at 19:18
  • $\begingroup$ The structure reminds me of this question Colorize bronchial tubes from wide to narrow. It uses UV mapping and a simple material shader -- For a smoke simulation, it might be easier to move the emitter(s) through the branches than to blow the smoke in there with the wind. $\endgroup$
    – Blunder
    Commented Mar 19, 2022 at 20:17

1 Answer 1


Example what I thought about Volumetric Shader ... here based on Ambient Oclussion with Inside option enabled (you can try also these OSL scripts if some will works better).

Probably can be used also as Density factor for Particle System ... ?

First I Decimated whole mesh to make lighter topology and deleted all inside mesh parts. You can do that easily by selecting one inner vertex and press L key (Linked), but first you would have to delete loops of a three veins ending open to inside.

enter image description here

For Volumetric you can animate Color Ramp to get impression of filling veins ...

enter image description here Under 2.93 I used Multiply by Math node ...
for 3.2x has to be used Vector Math node instead.

enter image description here


  • works for 2.93 and 3.2 (some bug for 3.0 and 3.1)
  • link to OSL script technique works, but for me only as internal text (not externally)

Version for 2.93

In combination with some Noise texture you can try more smokish leaning effect.

  • 1
    $\begingroup$ This will work just nicely! Thank you so much for your input! $\endgroup$
    – Iam Hidari
    Commented Mar 20, 2022 at 18:03
  • $\begingroup$ Just a quick follow-up: this works nicely in Blender 2.93. However, for some reason I cant get it to work in Blender 3.0 or Blender 3.1. Which version did you use? $\endgroup$
    – Iam Hidari
    Commented Mar 22, 2022 at 9:47
  • $\begingroup$ I see ... :) I used 2.8 at home on very old machine. At work I see 3.1 has some problem, but seems to be fixed for 3.2 ... you would have to use to Multiply (more logical) by using "Vector Math" node (not the "Math" node that worked in 2.93) imgur.com/3n5eMiU ... later I will fix the answer. Thanks for notification :) $\endgroup$
    – vklidu
    Commented Mar 22, 2022 at 17:52
  • $\begingroup$ Great! Thank you very much! $\endgroup$
    – Iam Hidari
    Commented Mar 23, 2022 at 13:39

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