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I have 16 smoke emitters in a domain and 8 of them are active for the first 50 frames, and they turn off at frame 51 and then the other 8 activate which were turned off before. Instead of the first 8 slowly dissipating (dissolve enabled) the smoke just instantly disappears.

frame 50

frame 51

You will have to bake the simulation (my test run was up to frame 58 when I noticed the problem)

Cabbage
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  • I'm sorry I do not have the time nor the hardware to bake a smoke simulation with a resolution of 512, but I've set it to 100 for testing purposes. In this case I do not see any cutoff. I also disabled the secondary emitters to clearly see what happens after frame 50, but the smoke dissolves as expected. The dissolve time you have set is only 12 frames, so of course even after 7, 8 frames it's already almost completely gone. Maybe it just dissolves too quick for your liking? A higher resolution usually reduces the amount of generated smoke as well, so dissolving might seem even quicker. – Gordon Brinkmann Jul 10 '23 at 07:56
  • BTW ... for such effect (gas jet controllers) - smoke sim ... it doesn't seem to me as efficient solution :) – vklidu Jul 10 '23 at 08:39
  • @GordonBrinkmann I just ran a 100 resolution simulation after what you said and it didn't disappear like you explained. The only problem is a resolution of 100 isn't enough for the final animation. – Cabbage Jul 10 '23 at 09:19
  • @vklidu I originally used a cylinder controlled with shape keys that had a texture applied to it but after rewatching Interstellar I realised proper simulated gas would look better :) – Cabbage Jul 10 '23 at 09:20

2 Answers2

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As I mentioned in the comments, I cannot bake at a resolution of 512, but here is just a quick overview in which way the Resolution Divisions affect the appearance of smoke as well as how much influence the Slow option in the Dissolve settings has. You have disabled it, have a very high resolution and a very short Dissolve time.

In the comparison below, all smoke domain and emitter settings are the same and all images are rendered on the same frame, the only changes made are the Resolution Divisions from 50 to 150 and the Slow option being enabled and disabled. Since you need a high resolution you might consider increasing the Time for dissolving and/or enabling the Slow option, because as you can see a higher resolution results in seemingly less and slower rising smoke, and of course dissolving quicker without the Slow option.

smoke dissolve comparison

Just for info: Use Flow was enabled until frame #15, Time for dissolving was 20 frames (a little more than your example to give the smoke a chance to rise) and the images are rendered on frame #40.

Gordon Brinkmann
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    This was quite helpful, I changed a few settings for dissolve and that seemed to fix it. Not 100% sure what happened but I did a test run on 100 resolution, then an overnight of 512. I changed the settings back to what they originally were and did a 512 res bake this morning and that seemed to fix it :) – Cabbage Jul 11 '23 at 10:00
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Not an answer to your Q (for that see Gordon's A), just a tmp notes and alternatives :) ...

  • one thing is - it would be more efficient to create smoke domains per jet not for whole object
  • it could be even more efficient to bake just (one or two) animation for a single jet and redistribute baked cash for others jets with time offset
  • speaking to other options you could probably try Geometry Nodes (with sim nodes) or you can animate Mesh Volume and Displace Volume modifiers
  • or ... according to angle of view just by aimed texture

Speaking to Interstellar scene (if you mean this) ... It is more artistic than realistic reference :) but sure - it is your choice.

enter image description here

Real gas in space doesn't collide in waviness since there is nothing to collide with, that is why it appears as a cone with tip at space craft. That can be easily generated by animated volumetric material

SpaceX enter image description here

Sojuz enter image description here

vklidu
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  • That's a good... well, not answer to the question, but illustrated information/comment on how this could be approached better for efficiency and even realism. – Gordon Brinkmann Jul 11 '23 at 05:59
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    @GordonBrinkmann Sure :) .... that is what my first sentence is about (sorry if it isn't clear from that). – vklidu Jul 11 '23 at 06:43
  • It is clear, sorry that I tried to appreciate your contribution :D – Gordon Brinkmann Jul 11 '23 at 06:49
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    OK ... Thanks than :) Sorry for my english ... I red it as objection :) – vklidu Jul 11 '23 at 07:03
  • That's quite useful, I didn't actually know about the gas not colliding with anything, I always just thought it was bad camera quality not getting enough detail. I might use that for another animation if I end up making one but this gas is meant to be more cinematic :) – Cabbage Jul 11 '23 at 09:58