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Helo,

I'm trying to create a scene where I have 10 bubbles coming up in a bath with splashes one after another. If I put them in one big domain it bakes forever and the resolution division is way too chunky. And if I bake 10 smaller domains I get crazy with managing 10 different cache folders and keyframing the objects on and off at the right time.

Is there a way to create one nice simulation and duplicate it with a time offset, so I only have to bake one simulation and rotate the others and position them in different locations so they kind of look different from different angles?
Thx, A

Blender2.83.1

Ale
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In case you would be interested only in meshed fluid sim ...

enter image description here

  • export sim as Alembic (.abc)
  • import back (or into a new file)
  • duplicate (Shift+D)

Like that you can from one cache duplicate as many copies you wish and offset time by single parametr for each copy individually in ...

Properties Editor > Modifiers > Mesh Sequence Cache > Frame Offset

enter image description here

vklidu
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    @vklidu

    I'm struggling with importing the sim as abc back into the scene. It works great for the mesh but the particles(foam/bubbles) are imported as animations points. How do I implement them back as a particle system for the new object?

     – Ale Jul 21 '20 at 15:14
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    @Ale May I ask for what reason do you need convert them back to particles? If you need them render as objects, simply use instancing from Vertices. https://imgur.com/0nU9qDI Or if you really need the particle system you can append baked particle cache (stored in particle folder) into a new file. https://blender.stackexchange.com/a/91102/2214 – vklidu Jul 21 '20 at 20:10
  • Thanks a lot again! I just looked for a way to make the particles visible again, instancing is a good way, that I didn't know before.., but it really slow down the computer, but anyway it works! – Ale Jul 22 '20 at 11:21
  • @Ale - its the same system of instancing particle as object, so calculation should be heavy at very similar level ... but you mind want to render particles as Halo material? That is gone be a good Q :) you can ask a new one. It was easy to do in 2.79, but Im not sure about 2.8x. I wanted to assign particle system to these vertices without physics so there would be a particle stick to every vertex to render as Halo, but it doesn't work for me ... – vklidu Jul 22 '20 at 11:58
  • @Ale This might be an alternative to Halo? Check this answer, part - point cloud https://blender.stackexchange.com/questions/45481/halo-particles-dont-render-in-cycles – vklidu Jul 22 '20 at 12:09
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The duplicating and rotating is no problem, just copy the domain with Shift + D. But the time offset is a different thing. Let's say your simulation goes from frame 1 to 50. If you want to duplicate it with an offset of 10 so that it runs from frame 11 to 60 you have to duplicate the cache folder, rename the data file suffixes from _0001 - _0050 to _0011 - 0060 and then tell your domain that it should use this cache folder instead of the original one. You also have to adjust the "Frame Start" and "End" to 11 and 60.

Gordon Brinkmann
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  • Thanks! This means I will have 10 cache folders and I have to bake 10 simulations before I can render the animation. I'm looking for a workaround to have one single cache folder and refer the other 9 to the first. – Ale Jul 06 '20 at 09:29
  • Well, if you duplicate and rename them you will still have 10 cache folders, but you only have to bake once. Depends on how long the bake will take which is more suitable, renaming or rebaking. – Gordon Brinkmann Jul 06 '20 at 09:39
  • yes this makes sense! I'll try, but how do I rename the suffixes automatically? Is it blender intern or extern? I save the bakes in openVDB. – Ale Jul 06 '20 at 09:42
  • I use a freeware tool where I can drag and drop the files that should be renamed and give rules how they should be renamed. – Gordon Brinkmann Jul 06 '20 at 10:05
  • @GordonBrinkmann When I offset baked sim (by renumbering) and play anim it keeps last (or random) state of sim on beginning of anim (instead of first frame or nothing). Worst it renders solid block of domain in these offset frames. Any tip for preview or render then animate visibility? Thanks – vklidu Jul 06 '20 at 16:45
  • Hm, well that's always a problem if you animatie longer than the simulation, even without duplication/offsetting - the domain has no data what to do frame 51, when simulated up to frame 50. Keeping the last state could be desired as some kind of resting point. It depends on how you want the simulation to disappear? Simply vanish from one frame to another? Than maybe setup the domain material with a Mix Shader and connect a Transparent Shader to the second input. Animate the mix factor so it switches from 0 to 1. But if you want liquid or smoke to correctly flow away, you have to simulate more. – Gordon Brinkmann Jul 08 '20 at 06:17