FLIP Fluids Addon: A liquid fluid simulation tool for Blender


(bernardothecat) #505

I’m going to throw a RX 580 8GB at it until the dust settles a bit. Nvidia RTX cards will not be implemented anytime soon (focus is on 2.8), AMD will release their first pro 7nm card later this year, and Navi is do out next year. I would consider a few Vega FEs if the price is right.

Have fun with your 2950 build!

(lumpyoatmeal) #506

Thanks. I’m back in the waiting game. I’m also waiting to see what AMD does with GPUs this year. And I think it might be prudent to get a motherboard with the upcoming 499 chip rather than the current 399 one.

(RLGUY) #507

Check out our new FLIP Fluids + Fracture Modifier animation and breakdown:

Three days of simulation and eight days of rendering!

And some more progress/testing on the surface tension feature:

Some cool trickling and droplets off the beard happening! Once the surface tension feature is stable, we will begin uploading experimental builds of the next version so that you can try out the latest new features.


Hi, I’m mostly using the FLIP Fluids Addon in Blender 2.79b on Mac OS and Debian Linux.
Lately, I noticed that the baking process gets stuck sometimes. Blender keeps saying „Baking in progress“ but CPU Usage drops down to a few % and no new frames are being calculated.
When I run the simulation from the command line the output looks like this:

12-Oct-2018 07h51m32s COMPLETE    Constrain Velocity Field
12-Oct-2018 07h51m32s BEGIN       Update Marker Particle Velocities
12-Oct-2018 07h51m32s COMPLETE    Update Marker Particle Velocities
12-Oct-2018 07h51m32s BEGIN       Delete Saved Velocity Field
12-Oct-2018 07h51m32s COMPLETE    Delete Saved Velocity Field
12-Oct-2018 07h51m32s BEGIN       Advect Marker Particles
12-Oct-2018 07h51m33s COMPLETE    Advect Marker Particles
12-Oct-2018 07h51m33s BEGIN       Update Fluid Objects
12-Oct-2018 07h51m33s COMPLETE    Update Fluid Objects
12-Oct-2018 07h51m33s BEGIN       Generate Output Data
12-Oct-2018 07h51m34s COMPLETE    Generate Output Data

*** Time Step Stats ***

12-Oct-2018 07h51m34s BEGIN       Generate Surface Mesh
Fluid Particles:   880182
Fluid Cells:       198515

Pressure Solver Iterations: 53
Estimated Error: 2.35271e-07

Step Update Time:   21.413

12-Oct-2018 07h51m35s

Frame: 289 (Step 2)
Step time: 0.00912118 (100% of frame)

12-Oct-2018 07h51m35s BEGIN       Update Obstacle Objects
12-Oct-2018 07h51m35s COMPLETE    Update Obstacle Objects
12-Oct-2018 07h51m35s BEGIN       Update Liquid Level Set
12-Oct-2018 07h51m35s COMPLETE    Update Liquid Level Set
12-Oct-2018 07h51m36s BEGIN       Advect Velocity Field
12-Oct-2018 07h51m40s COMPLETE    Advect Velocity Field
12-Oct-2018 07h51m40s BEGIN       Save Velocity Field
12-Oct-2018 07h51m40s COMPLETE    Save Velocity Field
12-Oct-2018 07h51m40s BEGIN       Apply Body Forces
12-Oct-2018 07h51m41s COMPLETE    Apply Body Forces
12-Oct-2018 07h51m41s BEGIN       Solve Pressure System
12-Oct-2018 07h51m49s COMPLETE    Solve Pressure System
12-Oct-2018 07h51m49s BEGIN       Constrain Velocity Field
12-Oct-2018 07h51m55s COMPLETE    Constrain Velocity Field
12-Oct-2018 07h51m55s BEGIN       Update Marker Particle Velocities
12-Oct-2018 07h51m55s COMPLETE    Update Marker Particle Velocities
12-Oct-2018 07h51m55s BEGIN       Delete Saved Velocity Field
12-Oct-2018 07h51m55s COMPLETE    Delete Saved Velocity Field
12-Oct-2018 07h51m55s BEGIN       Advect Marker Particles
12-Oct-2018 07h51m55s COMPLETE    Advect Marker Particles
12-Oct-2018 07h51m55s BEGIN       Update Fluid Objects
12-Oct-2018 07h51m55s COMPLETE    Update Fluid Objects

This example sat like this for two days. And it always seems to stop after „COMPLETE Update Fluid Objects“.
When I restart Blender I can continue baking but often it gets stuck again after a few more frames.
I reproduced this with plugin Versions 1.0.2, 1.0.3 and 1.0.4a.
I couldn’t reproduce this under Windows yet, but that might be luck because I don’t often use Windows.

This might be an issue with long simulations (10000 frames and more) because this problem didn’t occur when I was doing shorter simulations.

Has anyone else here experienced this or did long simulations without problems?

  • Marco

(vollstock) #509

Does anyboady have an idea of how to create something like this?

I actually need to create an asteroid impact for work. Doesn’t need to look perfekt, it’s supposed to be a freeze frame of the explosion that I can then 3D-Print and place a real meteroid in a museum.
No colour, no white water, just the geometry of the water splash.

(RLGUY) #510

Hi Marco,

Thanks for the report and simulation log. This is a known issue for Linux but we have not had any reports yet of this issue for Mac OS. Is this issue also happening when you are using Mac OS or is this happening on both Mac/Linux?

Unfortunately we are not able to reproduce this issue on our systems, so we have not been able to debug this issue yet. Are you able to attach the scene for us to test? Alternatively, you may send the scene to [email protected].

One method to go about this could be to drop a meteor shaped obstacle into a pool of fluid. I would enable world scaling and set the scale to a large value to create an appropriate size for the physics.

Here is a quick example of what this setup could look like:

(vollstock) #511

That’s exaclty what I’ve done. But however large I set the world, it always looks like something falls into water, not like planetary sized desaster. An explosion thaz size would consist of masses and masses of spray water and you would hardly see any splash at all.

The guy in the video uses a force under water but that is a future feature if I understand correctly.

(lolwel21) #512

Not sure how you’ve been doing it, but most of the sims I’ve seen use a meteor that is going way too slow. The way he does it is likely not supported in Blender, but with Blender Forces (given FLIP supports them) would be a Force Field empty with an animated strength and either spherical or conical falloff.



thank you for your reply!
This issue happened on Debian Linux 9 as well as on Mac OS 10.13.6.
On Mac OS I tried to bake this simulation:
halting_simulation.blend (1.1 MB)

But I have the feeling that the problem occurs more frequently on Linux.
On Mac it’s harder to reproduce. Today I baked the attached simulation to Frame 3500 without any problems whereas it got stuck twice until Frame 2500 yesterday.

I’d be happy to run some tests for you if that helps debugging :slight_smile:
But I can totally understand that you are focusing on developing the addon for Windows. I bet that is much work already.



for me personally, use of fluids looks bad for this sort of vizuals
in high velocity impact, so much energy is released that fluids vaporize :wink: even water at sides would disperse so much that it would look like spray, rather take a loot at the real thing – an A-bomb detonation

(vollstock) #515

I thought the same and started experimenting with a mix of a fluid splash and a smoke sim.

(lumpyoatmeal) #516

All of the youtube tutorials that I could find for Dynamic Paint that use the Surface set to Vertex (as opposed to Image Sequence) used the Blender Internal renderer instead of Cycles. But I found this one and he’s using a fluid simulation’s fluid for the Dynamic Paint brush. I’ve done some minimal experimentation and it seems to work with Flip Fluids if you use the fluid_surface mesh for the Dynamic Paint brush. I found it a little easier to see it painting if I set the brush’s Paint Source to Mesh Volume + Proximity. I’m hoping you guys can come up with some interesting results using this technique.



is it possible to get more in depth instruction on how the ocean modifier can work with flip fluids? it’s been done a couple times – but i still don’t quite understand how the displacement mesh from the ocean modifier loops back in and i think i am missing something with the vertex group on the fluid itself…

this is exciting stuff!

(RLGUY) #518

This looks like a nice resource, thanks for sharing! I have been meaning to experiment with creating wetmaps, but have not had a chance to try it out yet.

This is something we are currently experimenting with for a tutorial. I don’t entirely understand how the method works myself, I’m not very knowledgeable with these features/areas of Blender and have not tried out the method.

So far, these videos/comments are what I have found about the method:

Sorry that I am unable to give more exact details on how this effect is achieved. Perhaps a more experienced Blender would be able to share their knowledge.

And here’s a quick update on the current status of the FLIP Fluids addon! It’s been a while since I have updated in this thread.

New Experimental Build Available Nov. 22nd

We will soon be updating the Blender Market product to include experimental builds of the current state of the next version. This will be to give you access to the latest features! We will be uploading the first experimental build on Thursday. Some exciting new content will include:

Performance Improvements

In version 1.0.4 we added some performance improvements to the surface mesh generator. Since then, these performance techniques have been testing very well on other users’ systems. Lately we have expanded using these techniques to other simulation calculations to boost performance. We have also been carefully looking through the code to see where we can add more multithreading improvements.

We’ve spent the last two weeks heavily optimizing the FLIP Fluids engine, inserting over 50 timing probes to see where we can shave off fractions of a second! After 2500 lines of code added, 1000 removed, check out these incredible CPU and timing improvements:

New Feature: Surface Tension

An exciting new feature is the surface tension solver that we have been working on!

Can you tell us more about what surface tension would be?

Surface tension can be thought of as a force that pulls a mass of fluid inwards. The force acts on only the surface of the fluid and depends on the curvature of the surface. Sharper curvature -> stronger force. If a blob of fluid is left to float in zero-gravity, the surface tension force will eventually pull the fluid blob in to form a perfect sphere.

Surface tension can be imagined as if there is a stretchy thin film wrapping the fluid mass. Suface tension could be viewed like a water balloon where the rubber balloon is the stretchy film pulling the mass of water together. If you throw the water balloon, it will jiggle/oscillate through the air as the balloons tension tries to pull together the mass of fluid.

Surface tension effects in nature such as droplets forming/merging, dripping strands, thin fluid sheets, is more noticable when viewed up-close or in slow-motion. When viewing a liquid from a distance, such as looking at the waves of the ocean, surface tension effects can be less noticable. In simulation, having a surface tension parameter helps improve realism for these small-scale effects. Without a surface tension force, splashes tend to be more chaotic since there is no cohesive force to pull the fluid together, which may not look realistic for a small scale effect.

Within the addon, the surface tension parameter will be located in the World panel under the viscosity setting. The parameter will work similarly to the viscosity setting: there will be a checkbox to enable the surface tension solver and a number parameter to control how strong the surface tension force will be.

Here are some animations/images we’ve created while testing the the new solver:

For the experimental build, we will also be including example .blend files of the animations above to get you started with surface tension.

Minor Tweaks and Features

There will also be included some small bug fixes, tweaks, and features:

Blender Market Black Friday Sale

During November 23rd to 26th, the Blender Market will be having a BlackFriday/CyberMonday sale. A whole tonne of awesome products will be on sale for 25% off, so this is the time to get those plugins/assets you’ve been eyeing!

- Ryan

(IceChest) #519

Wow those are some serious speed improvements! Thank you. Can’t wait to try it out tomorrow :slight_smile:

(RLGUY) #520

I was a bit ahead of schedule and finished the release early about an hour ago. The product has now been updated with the new build. Release notes can be found at the bottom of the product page and descriptions of new example scenes can be found here!

(IceChest) #521

I noticed! Performing some basic speed tests now

(IceChest) #522

I baked the strawberry splash with the same settings of 320 cell resolution and 120 frames. It was 66 minutes total with an i7-8700K at 4.3 GHz

(Klutz) #523

Is there an experimental Linux release as well? If so, where could I download it? (I’m sorry, but I keep forgetting how software updates on the Blender Market work…)

(RLGUY) #524

Since version 1.0.2, Windows and experimental Linux/OSX support have been included all in the same installation file. Linux support is still experimental due to a bug that may cause your simulation to ‘halt’ that we have not been able to solve. Details here: https://github.com/rlguy/Blender-FLIP-Fluids/wiki/Operating-System-Support#linux

You can find links to product downloads in your Blender Market account orders section here: https://blendermarket.com/account/orders

If you purchased the product without creating an account, then you may find links to downloads in the purchase confirmation email. Alternatively, you can also create a Blender Market account using the same email that you purchased with and your account should be loaded with your purchased products.

When updating the addon, make sure to first uninstall the previous version before installing the new version. Installation/uninstallation instructions can be found here: https://github.com/rlguy/Blender-FLIP-Fluids/wiki/Addon-Installation-and-Uninstallation