frogurt Posted August 9, 2014 Share Posted August 9, 2014 Hello everyone, I'm pretty new here, asking this to more experienced users hoping to find a fix. Basically I am running a FLIP sim on Houdini build .376, ocean simulation with a boat geo. The container is quite big in width and length, 3 units deep and the particle separation on splashtank is currently set to 0.04, at this value already my RAM is almost completely taken, i tried to untick allow caching on the DOPnet and resetting sim with no luck, as soon as I dive into the DOPnet my RAM fills up to about 31GB, I currently have 32GB total. I've read in another thread that this might be related to the TBB allocator on Windows, which I am using, but seems like this issue has already been fixed with a previous release. Haven't tried the other solution yet, trying to overwrite the .dll file of H13 with the one coming with H12.5, wondering if meanwhile anyone feels kind enough to tell me what i'm missing here, cause surely i am Quote Link to comment Share on other sites More sharing options...
danw Posted August 9, 2014 Share Posted August 9, 2014 (edited) It may be a bit unhelpful, but it may just be because fluid sim takes up a huge amount of RAM. Boats-on-oceans is about the most demanding type of fluid sim you can attempt, and there's a lot of work that goes on trying to work out how to scale it up without it becoming unworkable. You can trim your ram usage to the bare minimum by pre-caching all SOPs that are sourced into the DOPs network to disk. Emission, collisions, sinks, etc. Make sure you only have File nodes reading straight from disk and passing straight into the sim. As a general rule, save RAM by ensuring that any parts of your scene using SOPs make gratuitous use of the Unload flag. A good general rule is, if a SOPs node is feeding its output data to two or more downstream nodes, leave it loaded, otherwise it'll cause the network above to cook twice... select all nodes that only pass down to one other node, hit "t", and then tap in the column that looks like a recycling symbol (three arrows in a circle), and those nodes will now always immediately release any RAM they were using the moment their cooked data has passed downstream. With all the memory usage trimming done, you'll still hit 32GB of RAM at some point above maybe 40-50 million particles (depending on the resolution of the underlying field data too, as that also takes a pretty large chunk of memory). At that point you have to start looking for ways to use that limit more effectively for your specific shots, as there's really no other way beyond installing more RAM. (and even that has a limit to effectiveness... at sim that takes up 128GB of RAM would probably be taking a week or more to sim on even the mightiest of workstations) (Also as a general rule - if you make any optimisations, or just before you kick off caching any sim out to disk... save your scene (with Manual mode on, so nothing bakes on scene-load), close everything down, load the file fresh, and hit go. Once Houdini hogs up some ram, it doesn't always give it back until you load up again, even if you made the changes to stop it) Edited August 9, 2014 by danw Quote Link to comment Share on other sites More sharing options...
frogurt Posted August 10, 2014 Author Share Posted August 10, 2014 Thanks danw, I'll definetly use those advices, as an unexperienced user I'm still looking for useful hints on how to speed up your scene and global tricks in Houdini. It impressed me moving from 3GB to 31GB of RAM just for cooking the particle separation on frame one and having it on viewport! Will keep on tweaking though, thanks again for your reply! Quote Link to comment Share on other sites More sharing options...
LukeLetellier Posted February 10, 2015 Share Posted February 10, 2015 I'm having similar issues; except for me the RAM totals are starting out medium sized & building up with each frame that's simulated; so over the course of 100 simulated frames I might accumulate an extra 25 GB of RAM that's just sitting around. If I save the scene & restart Houdini, I can pick up right where I left off with minimal RAM filled. If I don't do that, and all of my RAM fills up Houdini will just shut down automatically. Is there a script of some sort that I could use during my simulations so that the RAM cache is flushed after every X frame? Or something that would allow me to run a sim overnight without filling up & forcing a shut off after a few hours? Quote Link to comment Share on other sites More sharing options...
danw Posted February 12, 2015 Share Posted February 12, 2015 (edited) For heavy FLIP sims, you really need to explicitly disable caching on the FLIP object. I think caching still needs to be left on for the main DOP network to operate correctly, but you can tell the FLIP object specifically to skip caching - go into the DOP network, select the FLIP Object node, select the Creation tab, and untick "Allow Caching" This of course assumes you don't want to interactively play back the sim, and that you're caching it all out to disk. It may not entirely solve your memory issues, but it should go some way to reduce them. If you want to reduce further, look at pre-caching any SOP sources and loading them from disk straight into the sim (as per my tips earlier in this thread) Edited February 12, 2015 by danw Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.