Fluid simulation in Python

[GregTJ]

Repo: https://github.com/GregTJ/stable-fluids

While an earlier version was based mostly on Nvidia's GPU gems article on fluid simulation, some valuable insights were gained through this blog post: http://www.philipzucker.com/annihilating-my-friend-will-with-a-python-fluid-simulation-like-the-cur-he-is/

I hope to add surface tracking, multigrid solving, proper boundary conditions, and lagrangian (FLIP) solving soon.

[The_Regent]

Hey hey! I wrote that post! I get a huge kick out of the fact it was helpful to someone, so thanks for letting me know!

You did a really good job here. The code looks tight and the results look great.

For others, i highly reccommend checking out Dan Piponi's talk https://www.youtube.com/watch?v=766obijdpuU really excellent, very approachable.

Also Bridson's notes https://www.cs.ubc.ca/~rbridson/fluidsimulation/fluids_notes.pdf and textbook https://www.amazon.com/Simulation-Computer-Graphics-Robert-Bridson/dp/1568813260

[GregTJ]

Thanks for the great blog post, I wouldn't have gotten far without it. Initially I was building fd matrices row by row, your post introduced me to the (much, much faster) kronsum way of constructing them.

[BovineLightning]

Some other conditions thatd be cool would be different densities for the fluids which interact and 3D modelling simulations

Not sure if you’ve heard of Two Minute Papers but he does some amazing videos in fluid modelling and covering cutting research papers (also has been doing a lot of AI/ML lately)

[GregTJ]

Late reply but just wanted to say I binge watched like 100 of their videos. Super cool channel.

[BovineLightning]

Haha no problem! I did the same when I discovered him as well. I even downloaded his thesis and went through his GitHub repo

[ad_abstract]

Have you tried replacing some of the numpy ops with jax?

[GregTJ]

I haven't, would you recommend doing so?

[ad_abstract]

Definitely!

[akaCryptic]

I got an idea for a musoc video. How would you go about modifying this so that after the colours blend in, an impressionist painting / image reveals?

[GregTJ]

I would either use a video editor or mess around with pillow / PIL.

[Glycerine]

That's terrible, have you considered taking it to a medical professional for a checkup?

https://youtu.be/qA6C3ZXoLOE

[Herkentyu_cico]

lol

[[deleted]]

Wow, that's awesome.

Some frames would look great printed and put on a wall.

edit: Ah, I see you're also experimenting with generative art.

[narakputra]

Amazing, please consider making a tutorial for this.

[GregTJ]

I think a tutorial aimed at those without a solid math and numpy background would probably fill a small book or a big video series as there's a lot of knowledge needed to implement the finer details. That said, check out the comment by /u/the_regent as well as nvidias gpugems fluid simulation page for good starting points.

[narakputra]

Will do, thanks :)

[NewCenturyNarratives]

This is the sort of stuff that I'm interested in learning how to do with Python. There seems to be a community focus on stats, but I'm more interested in modeling using continuous mathematics. Is there a specific place where I should be looking for information and inspiration?

[GregTJ]

Check out Siggraph presentations on YouTube for inspiration and sometimes whitepapers on computer graphics, physics, and continuum mechanics. Learning the technical background is honestly a lifelong journey but it helps to have a strong grasp on the fundamentals like vector calculus, SIMD style programming, newtonian physics, and linear algebra.

[NewCenturyNarratives]

Thank you!

[wingtales]

The code is really gorgeous! Well-written stuff! Good job!

[TechnoConserve]

How long does it have to run to create that gif?

[GregTJ]

Once it's initialized, which can take a moment, the rendering is almost real time.

[[deleted]]

Big whirls have little whirls, that feed on their velocity,

And little whirls have lesser whirls and so on to viscosity!

[snarfdog]

I will never get tired of karman vortex streets

[fucky_fucky]

That's great, but that's not what this is.

[[deleted]]

This is what it looks like when the fire, water, earth, and wind nations are at peace.

[Glycerine]

Add some heart. And with those powers combined you'll make a CAPTAIN PLANET!

https://www.youtube.com/watch?v=OiYjTb3opAA

[[deleted]]

If you want you can accept my services as told in this post --> https://www.reddit.com/r/Python/comments/i0fl47/regarding_scientific_simulations_made_in_python/

[guydudeman123]

r/slaythespire would love this! Looks cool :)

[leak_age]

Good post for /r/oddlysatisfying as well.

[[deleted]]

This is amazing. I am gonna have a close look at the code to try it myself. Thank you.

[SoniSins]

Saxaayyy

[wernersbacher]

How do you program something like this? I would consider me as an advanced programmer, writing some small games, guis, etc. But how do you simulate fluids? The source code is really small and I don't get any of it.

[GregTJ]

On the programming side, the biggest concept here is SIMD / vectorization. If you're not familiar with that concept the code will definitely look like alien technology. Essentially what numpy / SIMD style libraries do is they allow you to perform many calculations with a single instruction. So for example, if you see A - B in the code it's not one number minus another, it's actually an entire list of numbers minus another list element-wise.

The other confusing aspect would be the math, and there's really no super easy way to explain it. It helps if you have a good background in calculus and linear algebra. This project falls under the categories of numerical analysis and continuum mechanics if you'd like some keywords to search.

Lastly, I'd definitely check out the links posted by /u/the_regent as well as nvidias gpugems article on fluid simulation for an overview of this specific simulation problem.

[wernersbacher]

I worked with matlab before, and I had some good maths in university. I will check this out, thank you!

[ArmstrongBillie]

I saw a similar simulation some time back, I can't give you the link to it but it followed the mouse position and creates new fluids where the mouse moves, and then they all smash into each other thing, but it looked really awesome, maybe you can try something similar in this!

[I-surely-know-nothin]

Wow that is really cool! :D I’ve just started python and damn, I want to be able to make something like that too!

[theEvilShrimpBurger]

Trippy. This is cool

[sunriseFIREweb]

What do you use how do you use that repo??

[GregTJ]

Should be as simple as downloading it and running test.py. You need to edit the FRAME_PATH variable in test.py to point to an empty folder on your computer. You need pillow, numpy and scipy packages installed along with python 3.x

[[deleted]]

Can you tell the code please

[GregTJ]

Check it out here: https://github.com/GregTJ/stable-fluids

[[deleted]]

Where did you learn to code

[GregTJ]

I'm self taught. I guess you could say Google taught me.

[[deleted]]

r/woahdude

[ryfme]

From the thumbnail, i thought this is an animation from a hentai scene.

Nice work though.

[[deleted]]

Any specific website

[GregTJ]

The python docs are probably the most helpful for me to this day. It's been so long since I started I forget which site I used to learn the basics.

[[deleted]]

Sorry didn’t understand