» StableFluids
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plugin navier-stokes C++
Credits: Jos Stamhttp://www.dgp.toronto.edu/people/stam/reality/Research/pdf/GDC03.pdf


This project was a research project for the #node17 visuals and wasn't really aimed for production. It quite strictly reproduces the credited paper, since it mainly served as a reference for evaluating other algorithms and implementation attempts. The only deviations are the additional vorticity confinement routines, eliminating the restriction to a square and evenly spaced base grid, and using Jacobi instead of Gauss-Seidel solver in order to benefit from SIMD instructions.

The repo demonstrates one way how to take advantage of c++'s native speed (SSE instructions) in vvvv without the need for two separate dlls and interop.
https://github.com/woeishi/StableFluids for detailed info


all nodes come 2d and 3d versions

  • StableFluid: Creates and holds a fluid simulation space
  • Evaluate: Drives the fluid simulation, giving access to global parameters
  • SetVelocity / SetDensity: Sets the velocities/densities of the entire fluid simulation space
  • AddVelocity / AddDensity: Adds velocities/densities to the entire fluid simulation space
  • AddRadialVelocity / AddRadialDensity: Adds velocities/densities around the given center to the fluid simulation space (think of it as an emitter)
  • AddRadial: Adds velocities and densities around the given center to the fluid simulation space
  • GetVelocity / GetDensity: Returns the velocities/densities of the enire fluid simulation space
  • Split: Returns the velocities and densities of the enire fluid simulation space
please check this list if your cpu is compatible


26.10.17 [13:45 UTC] by woei | 815 downloads
StableFluids_v1.0 x64 avx
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Older Revisions

25.10.17 [12:55 UTC] by woei | 203 downloads
StableFluids_v1.0 x64 avx2

timpernagel 25/10/2017 - 15:06

Nice! (And <3 for using GDI Renderer)

io 26/10/2017 - 11:10

Red "Evaluate" node here and then it crashes within 20 seconds.

woei 26/10/2017 - 11:26

@io thats a bit unspecific. x64 and you processor must support avx extensions. wiki says intel processors since 2008 and amd 2011

io 26/10/2017 - 11:53

This is a i7 Sandybridge with GTX 675xm, 64bit machine and latest 64bit vvvv

woei 26/10/2017 - 12:22

evaluate is red once you open the help patch? does tty say anything?

woei 26/10/2017 - 12:30

ah, might be incompatible with avx2 extensions. let me check, if i can compile with avx only

io 26/10/2017 - 12:32

Red on open.

woei 26/10/2017 - 12:50

uploaded another version which should be compatible for older cpus. check the list though.

io 26/10/2017 - 12:57

Ok working now thanks

kopffarben 07/11/2017 - 18:33

Hi Woei,
on github you write you do this in c++ because it must be unmanaged for SSE/AVX.

Just for info you now this System.Numerics.Vectors?
It provides hardware-accelerated numeric types (SIMD), suitable for high-performance processing and graphics applications.

woei 08/11/2017 - 13:46

@kopffarben: yep, i know.
however numerics apply those instruction on vectors. which in this case is maximum 3. i do that on iteration which maxes to 8.
the cost of this algorithm is not really complicated arithmetics but just running a lot of loops over a lot of arrays. thus unmanaged outperformes .net quite a bit, since there is no boundschecking on array access.
cli would of course also optimize into simd instructions, but only for cases where you exactly loop from 0 to length-1 of the array. and that is nearly never the case here, due to special boundary conditions in the algorithm.

i've also got the same implementation in c# with all the performance optimizations i could think of. still didn't get near the speed of c++

anonymous user login


~1d ago

joreg: infos to join tonights meetup are now here: 7.-worldwide-meetup

~1d ago

david: meetup starting soon. infos coming

~2d ago

joreg: also there is this nuget which sounds like an option: https://www.nuget.org/packages/TidyNetstandard/

~2d ago

joreg: if basic format tyding is enough you can use the XML ToString in VL

~2d ago

mediadog: Thanks @joreg. I really miss Tidy (XML), use it to clean up weather station data for realtime displays, any recommendations?

~2d ago

joreg: @mediadog thanks for the pointer. fixed.

~4d ago

mediadog: Clicking on "Missing in 64 bit builds" goes to page with warning no longer maintained, but betadocs link has no such info.

~8d ago

nanotekt: VL.stride yet again ...this time nonphotorealistic https://youtu.be/_aALr2wcj0Y ...wish evvvveryone to be well!

~13d ago

nanotekt: a brief VL.stride study https://youtu.be/B2Nlz5VZ9lM ...and a massive 'thank you' to the devvvvs!

~7d ago

everyoneishappy: @overtones this would require 4D noise, which is possible but not implemented in Fieldtrip