(Solved) Need help understanding Phoenix + TyFlow interaction
#1
I did a simple smoke sim with a moving sphere in PhoenixFD, called Phoenix mp4.

I wanted to convert the smoke movements into particles, I've been trying many things but I can't seem to get it. Birth fluid with Fluid Force, Birth Flow with Flow update, nothing really works. I tried going back to PFlow with Phoenix birth and Phoenix Force, and it works immediately.

Am I missing something really basic? I don't understand how to get it to work... I output every single thing in my phoenix source in case I need the data, but it seems that I don't, I don't know how to utilise it. Tyflow version doesn't seem to be moving at all, seems more like it's producing new particles only. Replace option in Fluid Force rollout made it move but it doesn't exactly follow the smoke movement.

I am using Phoenix 3.12. tyFlow 57 build. Any help is appreciated.


Attached Files
.mp4   Phoenix.mp4 (Size: 2.28 MB / Downloads: 7)
.mp4   PFlow.mp4 (Size: 2.22 MB / Downloads: 3)
.mp4   tyFlow.mp4 (Size: 1.3 MB / Downloads: 3)
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#2
Looks like you forgot to output the Velocity channel in your Phoenix sim. It's required for particle advection, and off by default.
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#3
Thanks for the reply. I have velocity channel, but I am still in confusion over how to use it properly. I tried turning it on in the birth fluid channel, and the result is tyflow fill the whole phoenix simulation box with particles, so I assumed it was superfluous data.

I am attaching the scene file here, if you'd like to take a look.


Attached Files Thumbnail(s)
   

.max   SmokeSim.max (Size: 948 KB / Downloads: 0)
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#4
Oh, it might be the Phoenix version itself. Please update to 3.14 Smile
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#5
(11-10-2019, 05:49 PM)tyFlow Wrote: Oh, it might be the Phoenix version itself. Please update to 3.14 Smile

Noted, will do. Thanks for the help! I'll post here again if it still doesn't work.
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#6
Updated the Phoenix to Nightly Build, 3.14. Redid the simulation, with all outputs checked just in case. Input grid channel is Smoke+Velocity, but the same behavior still happens. Once Velocity is ticked in Birth Fluid, the whole Simulation Grid is filled with Tyflow particles. I'm quite unsure what I am doing wrong at this point.

If you would like to replicate it, I just create a sphere, clicked on the shortcut to create large scale smoke sim, animated the sphere to move forward in 50 frames. Then using the result in birth fluid and fluid force.
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#7
Really not sure what is the problem. 
I did it now really quickly, and everything is working. 

ALL I did is checked "velocity" in Phoenix output... everything else, I didn't changed anything. 
Added fluid birth - picked container, added fluid force - picked container... and it works. 

Attaching you file... just re-sim (it's simple, low res sim), and it should work. 

Make sure you download the latest Tyflow (from today), because I did that, before doing this test.


Attached Files
.rar   Phoenix_sim_velocity_ty_flow_2017.rar (Size: 177.92 KB / Downloads: 2)
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#8
(11-11-2019, 10:25 AM)d4rk3lf Wrote: Really not sure what is the problem. 
I did it now really quickly, and everything is working. 

ALL I did is checked "velocity" in Phoenix output... everything else, I didn't changed anything. 
Added fluid birth - picked container, added fluid force - picked container... and it works. 

Attaching you file... just re-sim (it's simple, low res sim), and it should work. 

Make sure you download the latest Tyflow (from today), because I did that, before doing this test.

Thanks for the help. I'll try it out.
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#9
Yours works, and I think I understand where we differ. But I am not sure if my understanding is correct. Feel free to correct me.

Looks like the primary reason why my simulation doesn't work with tyflow is because I was simulating something that was moving in time, and I parented the sim grid to the sphere while it is moving, and the grid keeps expanding over time. I did this because it will be pretty fast to sim at the beginning frames before it started expanding. For illustration purposes, imagine my sphere is 50cm, and moving forward for 1000cm. and I created a grid of 70x70x70 cm instead of something like.. 70x70x1100 cm.

Tyflow produced particles correctly but as soon as it left the initial grid (since the grid is moving forward together with the sphere, even though technically the grid itself is adaptive and therefore expanding), it loses the fluid force influence and it is stuck moving in 1 axis only.

After gaining this knowledge, I tried creating a grid that encompasses my whole animation path, and did not allow it to move with my sphere, essentially covering the whole path with the sim grid. Adaptive grid disabled.

Voila, it works perfectly, and I am still using version 57.

So, can I assume that anything that uses adaptive grid, and when the particle left the initial grid size, is ignored by tyflow fluid force calculation?

Also, what's the use of velocity channel input in the birth fluid? It still fills my whole grid with particles that's not part of the smoke. I did the velocity output in the sim, but looks like tyflow detected those automatically, so there's no need to tick the velocity channel in birth fluid. The documentation stated that anything with velocity above 0 will spawn particles, Does that mean the whole grid has velocity above 0?
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