Fluid simulation unstability. Crashes, broken baking and system freezing.

Welcome everybody.

I would like to do some serious fluid simulations but fluid sim in newer Blender versions(2.57b + various graphicall builds) seems to be more buggy than in previous. Before I start working on real sims, I would like to do some stability/speed tests.

I bought a quite powerful pc some time ago, spec:

  • INTEL Core i7-2600k 3,4GHz 8MB LGA1155 (PCU)
  • ASUS P8P67 PRO rev3.0 (Motherboard)
  • GIGABYTE GTX570 1280MB DDR5 2xDVi/1x miniHDMI (Graphics Card)
  • 8GB DDR3 KINGSTON HyperX Genesis 1600MHz (RAM Memory)
  • OCZ 700W StealthXStream 2 (Power Supply)
  • SAMSUNG 500GB HD502HJ 16MB cache SATAII (Hard Drive)

System: Windows 7 Home 64bit

Some time ago I did a lot of fluid sim tests on my crappy almost 5 years old laptop (dual core 1.6 GHz, 2.5GB RAM 667 MHz, integrated graphic card). Even on this old and unsuitable for fluid sims machine I could bake fluids with resolution over 200/250 maybe more. Sometimes it crashed but it was quite stable.

Now on my much better pc I have a lot of crashes. I spotted several situations:

  • simulation resolution set over 200, sometimes even over 100
  • Blender can crash, freeze operating system (no reaction) or bake only part of frames correctly

I’d like to do bug(s) report and think about fundraise to polish fluid simulation if devs would be interested (preferably Daniel Genrich and/or Miika). I also tested graphicall builds with OpenMP (for multithreading) but with poor results. It is much more painful as I’ve got a 4 core CPU now (and I know a lot of people have much more powerful PCs).

I attach my test sceene made in official Blender 2.57b 64bit. I used “make fluid” operator and tweeked settings. I also applied scale to domain object, but tried without this also. If You could test and confirm bugs/system freeze it would be cool. Remember to set correct path to bake directory.

Write what You think about fundraising for simulation polishing (I know about gsoc but It would have quite different goals).

Best regards, Dawid. Sorry for my poor English.


fluidofficialtest.blend (440 KB)

Remember this…When Blender runs out of memory it crashes. So you are running out of memory.

Really, a final resolution of 350? Try a lower number.

Often, the fluid simulation work-flow is to calculate a lower final resolution, then apply a subsurf modifier to the resulting mesh to smooth it out. This is more memory efficient and can allow you to actually complete your work.

Write what You think about fundraising for simulation polishing
If you are serious about putting up money and you really do a lot of fluid work, why not just purchase or rent Real Flow?

Also, have you stress tested you new PC? Sometimes, even if you purchase an off-the-shelf PC it has been overclocked to meet it’s target specs. Heavy calculations over a long period of time can cause over-clocked computers to crash of fail.

Of course I know about Real Flow, Houdini fluids (now have 3 different types: grid based like elBeam in Blender, particles, and hybrid). There is also Naiad, ICE fluids (Lagoa) etc.

I’d like to use Blender fluids for now, and I don’t said that I don’t like to use other solutions/software because I already test Houdini, Cinema, XSI and Max. I don’t mind putting up money for software and I bought some (I do some coding too, and I know that developers have to eat and pay bill too. I know this can surprise many people, joke) but price tag is currently to high for me for software such as Real Flow or Houdini. I’m not complain, that’s fact.

I also think that if let say 50 people would be willing to spent e.g. 50$ this could be wise used by developer(s) to work on polishing this area of Blender. Of course those numbers are totally random. I have to email some developers and ask If They would eventually be interested in this project first. I don’t expect to get fluids capabilities like Real flow or even close but some bugfixing and speeding up by multithreading would be nice. Now we have a nice simultor but I’ve seen only several real use of it (I remember some commercial by Matt Ebb team, and russian fruity drink ad).

About my PC, I don’t think that Blender used all my RAM (with 350 res, certainly not with 200 res), and If i remeber right people used quite high resolutions (e.g. wave flooding city sceene). I know that good simulation isn’t only setting resolution as high as possible, but I could bake 200 res sim on my old crappy laptop and I can’t now with much better PC. I didn’t overclock my CPU and tested it using various software. It can have some flaws (I’ve heard about some problems with CPU model I own) but it is hard to belive that this could be only reason for incorrect Blender work.

About subsurf solution, of course I know it, but results are not so good. Thanks You for response.

Best regards, Dawid.