i wonder does your stars lose energy somewhere? because my stars just fly around forever and it seems a bit unrealistic, they never seem to find their equilibrium which i hoped would be a pretty galaxy like yours. yours seem more dense packed than mine
Is it a 2D or 3D simulation ? I'm working too on a cosomoligcal simulator, for now I'm still in the 2D configuration, but I don't get any main rotational behaviour like yours, even with collision handled with SPH. I use the Barnes Hut algorithm to accelerate gravity computation. Could you give some details about your implementation ? Thanks.
@VelRyphon It's 3D simulation, based on the model specified @ Nvidia's Nbody Paper (Google for the PDF and source code). It's quite a simple and naive simulation. (Uses no data structures simplifications, nor collision detection). I'll say your simulator is way more complex and interesting, in that sense.
I initialize my particles inside a two ellipsoid constrained space, and specify a speed vector in such way they all orbit in the same direction, to create the spiral rotation behavior.
@rdelcueto Ok thank you. I saw this NVidia paper. Indeed it's quiet a simple model. you're swirling rendering comes from your initial conditions, having already an orbiting rotation before you lauch it. I'm trying to get that rotation from scratch, with 0 velocity at beginning, only random positions in a sphere which induce gravitation interaction...
Is there a black hole in the middle, or are you just doing the n^2 operations? Also, How come there are no wild slingshot particles (when 2 particles get really close together).
@TheJesseLenney There's no black hole in the simulation, just the n^2 interactions between the n particles. To prevent the "wild slingshots", a smoothing factor is used, so that particles are never TOO close, and you can control the "slingshot" speed. Without it, you get a very erratic behavior, were most particles fly away from the galaxy center and never come back.
how big is the diffrence between the smallest mass and biggest mass?
ColacX 1 year ago
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i wonder does your stars lose energy somewhere? because my stars just fly around forever and it seems a bit unrealistic, they never seem to find their equilibrium which i hoped would be a pretty galaxy like yours. yours seem more dense packed than mine
ColacX 1 year ago
Comment removed
ColacX 1 year ago
Is it a 2D or 3D simulation ? I'm working too on a cosomoligcal simulator, for now I'm still in the 2D configuration, but I don't get any main rotational behaviour like yours, even with collision handled with SPH. I use the Barnes Hut algorithm to accelerate gravity computation. Could you give some details about your implementation ? Thanks.
VelRyphon 1 year ago
@VelRyphon It's 3D simulation, based on the model specified @ Nvidia's Nbody Paper (Google for the PDF and source code). It's quite a simple and naive simulation. (Uses no data structures simplifications, nor collision detection). I'll say your simulator is way more complex and interesting, in that sense.
I initialize my particles inside a two ellipsoid constrained space, and specify a speed vector in such way they all orbit in the same direction, to create the spiral rotation behavior.
rdelcueto 1 year ago
@rdelcueto Ok thank you. I saw this NVidia paper. Indeed it's quiet a simple model. you're swirling rendering comes from your initial conditions, having already an orbiting rotation before you lauch it. I'm trying to get that rotation from scratch, with 0 velocity at beginning, only random positions in a sphere which induce gravitation interaction...
VelRyphon 1 year ago
@VelRyphon MASSIVE BUMP but it looks like a good source of inspiration is youtube com/user/Nbodyshop
they have "big-bang" style starts, along with some SPH stuff to accurately model gasses.
DKM101 7 months ago
@VelRyphon Have you had any success implementing Barnes & Hut algo?
tclyue 1 month ago
Is there a black hole in the middle, or are you just doing the n^2 operations? Also, How come there are no wild slingshot particles (when 2 particles get really close together).
TheJesseLenney 1 year ago
@TheJesseLenney There's no black hole in the simulation, just the n^2 interactions between the n particles. To prevent the "wild slingshots", a smoothing factor is used, so that particles are never TOO close, and you can control the "slingshot" speed. Without it, you get a very erratic behavior, were most particles fly away from the galaxy center and never come back.
rdelcueto 1 year ago
i dig this nice question and nice answer was having problems figuring this out
ColacX 1 year ago
Is this video in real-time, or did you speed it up?
SomeHelpNeeded 1 year ago
@SomeHelpNeeded No realtime here (8192 particles). =)
On my Intel i7 @ 1.6, using 4 threads, it renders @ ~1fps.
rdelcueto 1 year ago
AWESOME!! xD
rojebrio 2 years ago