FLIP Fluids Addon: A liquid fluid simulation tool for Blender



The bubbles that get generated and trail a little underwater when the dolphin lands, is that a FLIP feature as well?

(lumpyoatmeal) #465

(This is not related to octopuscats’ remark.)

Is this a bug? I sometimes see bubbles generated under water where I wouldn’t think it would be possible. Doesn’t the existence of bubbles come from air being pulled into the water?



In layman’s terms…
Air, specifically oxygen, is already within - making the water (H2O). When circumstances are right & energy rises/forces fluid to the boiling point (or lower, if other gases are present ie. CO2) then the state of element changes (fluid to gaseous) & bubbles appear.
Similar magical appearance occurs with water engine propellers - Cavitation (wikipedia).
Know your chemistry & physics :wink:

IDK if this applies to computer models (sims) as i haven’t studied any yet.

(lumpyoatmeal) #467

Thanks. One of the things on my to-do list is to use a cylinder to make something like a drinking glass and have an object at the bottom spinning, at different speeds and with different frictions.

(Grimm) #468

As burnin said there is alway a certain amount of air dissolved in water. Fast motion can release this air hence the bubbles. There was an Israeli company making scuba gear that would extract this air using a centrifuge but I don’t know how well it worked.

(RLGUY) #469

Yes, those generated bubbles are a part of the whitewater simulation feature.

Are these growing bubbles what you mean?:


I suspect that this could be due to how the simulation is computed. The simulator tracks where fluid exists with a set of particles which are also used for meshing. The obstacle object would create a spinning vortex type motion in the fluid as it passes through. If the speed of the vortices are high enough, the spinning fluid particles can start to move outwards due to numerical errors, which are a natural side effect of simulation, creating a cavity in the fluid. Since the mesher generates a mesh based on fluid particle locations, this area ends up empty.

(lumpyoatmeal) #470

Yes, those are the bubbles. They’re getting bigger; the fluid sim is still running, as is the render.

(lumpyoatmeal) #471

Here’s a slightly longer version.


(tomiv87) #472

Hey, just downloaded the demo and installed it, but when I turn flip fluids on to any object it wont give me any settings. Any help?

I’m using blender 2.79b.


(RLGUY) #473

Hey tomiv87,

The FLIP Fluids Demo addon is a very limited version of the full release addon. The demo will only allow you to run predefined scenes at preset resolutions called test cases. The demo will still allow you to playback and render your test case simulation. A download link to the testcase/demo scene files can be found on the Demo Addon Page, or you can use this link directly: flip_fluids_demo_scenes-0.0.4d.zip.

- Ryan


Hello, i got the flip fluids add-on yesterday and I’ve been playing around with it and i made this animation

as you can see there’s a random light flicker, I’m trying to know why that happened so i can avoid it in the future.

all i did was changing the foam material to a simple emission shader


here’s the blend file water spark.blend (5.8 MB)

I also made a reddit post about this issue before knowing about this thread

(RLGUY) #475

Hey ARC9,

First off, that is a nice looking effect/render! My assumption for what is causing the flickering is related to this Reddit comment:

If this is made using the flip fluid addon, and you are emitting using particles from the foam / bubbles, then you will need to re-render the flickering frames. there’s a but that if you have the 3d veiwport open during rendering, some particles wont get rendered.

The 3d viewport can cause odd rendering problems if it is open while rendering large data with Cycles. This workaround often fixes issues during rendering.

As another comment mentioned, I would agree that it is a good practice to render into images rather than directly to video. With large renders, Blender could crash or the GPU could run out of memory which would would lead to a lost video. In the case of problems with individual frames, the images can be re-rendered. If the re-rendered images are consistently rendered wrong, then it is a repeatable bug that could be reported.

- Ryan

(Pavel_Blend) #476

High Viscosity:

(Rikolo) #478

Hi, are you planning on some dedicated forum for the addon? This thread provides useful info, but it’s really hard to digest.

(RLGUY) #479

I have thought a bit about this and it would be nice to have a forum where it is easier to keep track of separate topics. I do not have experience with setting up and maintaining a forum. Ideally, a solution would be simple to set up and not take too much time to maintain so that we can focus our resources on furthering development of the addon.

After some quick searching, it looks like Google Groups could be a solution. A concern that I have is that our userbase might not be large enough to have an active forum and would become stale and unused.

If anyone has any input/suggestions on this, that would be awesome!

(lumpyoatmeal) #480

What about blender.stackexchange.com? You’d have to add a dash for the tag; e.g. flip-fluid.

(lumpyoatmeal) #481

I think this has been brought up before? The fluid volume is decreasing.


Blend file: http://pasteall.org/blend/index.php?id=50335

(RLGUY) #482

Yep, this is a known issue: #326.

Amount of volume loss/gain can be amplified in turbulent flows with fast moving obstacles. If you still have the bakefiles, would you be able to export and attach a CSV of your simulation stats (FLIP Fluid Stats Panel). This will give me more info about how the simulator ran and could lead to a solution to this issue.

(lumpyoatmeal) #483

Here’s the blend file and csv file.


(Pavel_Blend) #484

How are things with variable viscosity?
In which version of the addon is it worth waiting for this opportunity?
And whether it will be possible to create multiphase liquid?
Like here: