Hi,

I am working on a simple FLIP sim. When I simulate with Particle Separation set to 0.1 (11k particles at the start), it caches all 500 frames without any problems. However, when I lower the Particle Separation to anything lower, Houdini gets hung at some point. With Particle Separation set to 0.05 (88k particles), Houdini hung at frame 23 and with 0.02 (1.4m particles) it got hung at frame 19.

The scene doesn't really contain anything special, just a few static geos for collision. Any idea what could be causing the issue?

This is on a Quad Core machine with 8G of RAM.

What do you expect with only 8 gigs of ram. Instead of trying to cache the whole sim to ram write it out to disk.

Rob

I am writing it out to disk using ROP Output Driver in SOPs…that's when it's getting hung

Your post mentions nothing about writing to disk using the ROP output driver. I am rendering and writing to disk high res FLIP fluid sims as I write this with no problems at all. Using H12.0.586 & 48 gigs of ram & X 2 xeon 2.4GHz 6 core processors.

rob

I would try rendering via command line, no guarantee its gotta solve your problem - but worth a shot. Good luck!

eitht.

circusmonkey
Your post mentions nothing about writing to disk using the ROP output driver. I am rendering and writing to disk high res FLIP fluid sims as I write this with no problems at all. Using H12.0.586 & 48 gigs of ram & X 2 xeon 2.4GHz 6 core processors.

rob

Yea sorry I forgot to mention that. Any ideas what could be causing the problem with my sim?

P.S. : Tried using HBATCH and render and the process still got stuck.

Is the process getting stuck, or are you running out of memory?

Run “top” in a shell (or if you're on Windows, do Ctrl+Shift+Esc to run the process monitor) and watch as you're running the simulation. If the Houdini process gets to within 10% of your physical RAM then you're likely running out of RAM and the machine is in swap. It's not actually stuck, it just means you need more RAM

Cheers,

PEter B

Hi Peter,

The TOP info at the point the sim get's stuck -

top - 19:34:07 up 2 days, 1:12, 1 user, load average: 2.28, 2.24, 1.84
Tasks: 231 total, 2 running, 229 sleeping, 0 stopped, 0 zombie
Cpu(s): 25.0%us, 0.2%sy, 0.0%ni, 72.3%id, 0.0%wa, 2.6%hi, 0.0%si, 0.0%st
Mem: 8178492k total, 7380152k used, 798340k free, 73236k buffers
Swap: 1952760k total, 387088k used, 1565672k free, 4900028k cached

PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
2716 i7959201 20 0 2766m 1.3g 72m R 100 16.3 45:18.27 houdini-bin

I am not sure about running out of memory because I believe I should be able to simulate more than 10k particles without running out of memory, especially since I am not caching to memory but to disk. Do you think there is something wrong with my file?

Nope, you're running out of memory

However, you can try turning off the Cache to Memory on the Dopnetwork, and write to disk solely…

Hi, thanks.

I am only writing to disk and the enable cache option on the dopnet is disabled.

Guess you need more RAM then, or less particles

I've gone as low as 80k particles and it still hung which led me to believe there was some other problem which I couldn't figure out.

Ah fair enough. I would suggest submitting to SESI's support then!

Ok, thanks I'll do that.

One thing that I've noticed is that it always gets stuck while evaluating GAS_Advect; irrespective of the frame. Sometimes on frame 19, 21, 22 or 25.

FIXED: For some reason the Wind force was causing a problem. When I tried caching to disk after disabling it, it worked perfectly.