Realflow Hybrido - Large Sim Crash out - Panick time?

Discussions about the use of Realflow
rich0550a1
Posts: 19
Joined: Mon Apr 16, 2018 2:23 pm

Realflow Hybrido - Large Sim Crash out - Panick time?

Postby rich0550a1 » Thu Apr 26, 2018 6:17 pm

Hi, out options after days into this project, maybe someone can tell me if I am missing a setting?

Large sim riverbed, going about 150 meters in RF

I get the Hybrido sim about half way down 16 mil particles. then it crashes out, usually on a frame about 800 frames in.

System: Dual Xeon 32 threads, 64 GB Ram, Win 7, No GPU options set, 5TB hard drive.

Scene setup:
K volume
Gravity
3 Three emitters from a dam at the end of riverbed with constant velocity of 3
Collision object: .1 cell size, Riverbed 150 meters long 150, 150k polygon, sd imported, solid body, volume inside (not a shell)
Collision object: Dam .1 cell size

Sim Options:
Substeps: General Steps: 1 min 16 max
Hybrido: Steps 1 min 1 max (also tried 1/150 and 1/2) (also tried (1/300 and 2/2)
Tim scale 1
Frames per second 60

Domain Options
Cell size .16 No particle sampling.

Object Options
Object grid size .1 ( or .16 or .2 )
Viscosity 0 (default)
Density 1000 (default)
Friction (default) 0 depth .1 interaction 1

The simulation continues when i disable the riverbed, when i turn it on again the sim crashes at a particular frame.

so far i have tried
- remodeling and re-importing the geometry as SD and ABC, its all quads ( i looked for overlapping faces in 3dsmax - none)
- deleting the frame 865 vdb and rpc
- clear memory, make initial state, limit and keep all speed to 0 and restart
- changed offsets on riverbed from .1 to .2
- time scale to 1 to .6
- substeps from very high to very low
- backing up 50 frames and starting from there same problem but often worse.

sorry edit trying to shorten


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ChristianZ
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Location: CH
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Re: Realflow Hybrido - Large Sim Crash out - Panick time?

Postby ChristianZ » Thu Apr 26, 2018 7:35 pm

Hi

sorry to hear that hybrido behaves so nasty with this sim. Do you see the same crashes when using the command line mode?

Crashes could be related to sharp changes within the simulation. Maybe adding a drag daemon or increasing the frame per second setting to even higher values could help.
Regarding the river bed object, what matters is that it is a closed object without open polygons (unless you use the shell mode). RF usually requires triangles.
RF10 standard + RFC4D

rich0550a1
Posts: 19
Joined: Mon Apr 16, 2018 2:23 pm

Re: Realflow Hybrido - Large Sim Crash out - Panick time?

Postby rich0550a1 » Thu Apr 26, 2018 9:20 pm

HI thanks I tried 100fps even. using 60fps right now, it seemed to help for a while, no error message in command line window.

not much experimentation with drag daemon will try, the particles are for sure moving pretty fast especially around the corners.

I just made the scene from scratch again just in case. the riverbed is closed. I made it in 3dsmax and zbrush, and then exported as SD file so its would be triangulated. Serveral iterations to make sure its manifold and with very clean topology even though it was orginally DEM data, created from real Lidar scans. Thats another story heh. The no messages about degenerative faces anymore those i thought were the problem was hopefull! but..

Will report back about the use of drag force. I have seen sims with .1 friction but opted not to do that since the river is pretty shallow and might be too many calculations.

Will 20-50 mil be doable would like it to have some detail. Also what options are available after simming. I mean how many things are safe to change without blowing up the sim? Resolution is not changable for sure correct? can i add and subtract kvolumes, collision objects mid sim or do I need to sim again for a couple days?

Sorry lots of questions here... how about Hybrido options like strickness? accuracy? cell transport value? or particle sampling in the domain? so forth.

Edit -- correction the river bed has 376k vertices and 735k faces. maybe too big?

Thanks!

rich0550a1
Posts: 19
Joined: Mon Apr 16, 2018 2:23 pm

Re: Realflow Hybrido - Large Sim Crash out - Panick time?

Postby rich0550a1 » Fri Apr 27, 2018 10:09 pm

trying again with fresh scene, 30k poly for collision object (riverbed)

also a long fill object to kind of prefil the river bed

steps 1 min 150 max general
steps 1 min 1 max Hybrido

and Dragforce Deamon .1 per your suggestion.

25 million so far

rich0550a1
Posts: 19
Joined: Mon Apr 16, 2018 2:23 pm

Re: Realflow Hybrido - Large Sim Crash out - Panick time?

Postby rich0550a1 » Tue May 01, 2018 4:18 pm

30m Particle couple days in now, 20 min a frame

no crashes that drag force may have done the trick. is it better than limit and keep? Thanks for help

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ChristianZ
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Re: Realflow Hybrido - Large Sim Crash out - Panick time?

Postby ChristianZ » Tue May 01, 2018 6:26 pm

It seems to be on a good way, great news!

If drag is better than other strategies, I don't know. It probably always makes sense to limit the use of hardware resources and extreme situations within the simulation. Unfortunately I don't have fast hardware here and so I have not done much with hybrido so far because the sims became way too slow most of the time. Now, I am using much more the RF-Plugin integrated in Cinema4D for small-scale sims with GPU-acceleration (the plugin has no hybrido).
RF10 standard + RFC4D

rich0550a1
Posts: 19
Joined: Mon Apr 16, 2018 2:23 pm

Re: Realflow Hybrido - Large Sim Crash out - Panick time?

Postby rich0550a1 » Wed May 09, 2018 2:29 pm

Update

Thanks for help.
I have a nice long week into this sim again. with no crashes. Now made initial state. I had not saved saved out VDB. But it seems will need that for foam correct?

When I reset to initial state and begin the sim with VDB and RPC checked it is crashing again. Can this be done saving VDB after making initial state?

Is there some things I can drop out in the VDB options that are not needed for HY secondaries ?

Also not sure what is going on but went from 18min a frame with 36m particles to 6 min a frame after resetting to initial state? What gives? Why would the sim time come down its the same HY domain nothing changed same number of particles.

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