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I am trying to make a fluid simulation in a very simple dam. I have read tons of documentation, videos and forum posts however I am not able to resolve my problem perhaps because I don't know exactly what to call this phenomenon.

enter image description here

As you can see the fluid is not falling down and is instead in some sort of cube that is non existent. I have messed with tons of settings but I just have no idea what is causing this.

I did use a sphere at first where the same thing happened but after a while the fluid did fall down. However it fell through the effector collision despite having a thickness. That's another problem that might or might not get resolved after this gets resolved.

Is this issue related to the domain? Some folks on reddit already told me to apply transformations to the domain and reset its Origin to Geometry. However both of those didn't do anything.

enter image description here The domain

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    $\begingroup$ Two options - delete all messed liquid sim and start from beginning to be more clear what you are doing. Second upload your simplified file (that still produce issue) via blend-exchange.giantcowfilms.com and paste code into your question to let as check your setup. Thanks $\endgroup$
    – vklidu
    Commented Nov 14, 2020 at 21:33
  • $\begingroup$ @vklidu I'm not sure what you mean with "to be more clear what you are doing.". I already rebaked my sim multiple times. I have tested a simple sim before doing this one and that one worked fine. There's no code involved so I don't really get what you mean with that either. $\endgroup$
    – Aperture
    Commented Nov 15, 2020 at 18:31
  • $\begingroup$ You wrote "I have messed with tons of settings,,,", anyway I m going to check your file ... $\endgroup$
    – vklidu
    Commented Nov 15, 2020 at 19:50

1 Answer 1

Reset to default
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ISSUE - your Effector object uses under Settings > Surface Thickness 10.
It make the distance from liquid.

SOLUTION - reset to default value (with right click) or type zero (or something smaller).

What can be enhanced

  • Your Domain is very large = wasted divisions for nothing, and long calculation time
  • Effector topology necessarely complicated = heavier calculation
  • "Tube" from one container to another container very thin = you will have to increase divisions much higher to get enough details to let flow liquid through this thin part if you imagine grid divisions than will be used in this part.
  • Inflow is very small = take a lot of time to fill container before liquid starts flow into another container
  • Cache set only up to 250 frames = it is not enough frames to get result

Recommendations

  • Create Effector object with clean topology, one sided
  • Let recalculate Normals Shift+N inside (you can re-check with Face Orientation overlay

enter image description here

  • Use Solidify modifier if needed to protect from leaking liquid (Solidify has to be before Fluid modifier) or set some low value for Surface Thickness or set some sub-step, but this increase calculation time
  • Scale Domain as small as possible (just reminder - number of divisions set for domain is represented by small cube in a corner and means how many times is divided the longest edge of domain)

enter image description here

  • Inflow make bigger or increase Initial Velocity

enter image description here

  • Before you are not sure about elementary functionality disable Meshing feature that consume computation time as well (to see if liquid goes in right directions, fills what is needed to be filled in given time, and is not leaking in any part ... the coloured particles are more than enough in Replay mode).

What bothers me is cache that should refresh any time some parametr is changed, but that is not happening. What I do is to change divisions about a step back and forth.

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