Hello
i just wanted to ask what is the best workflow to cache out particle fluids.
in “Intro_to_Fluids_in_Houdini” ROP is used which is (if i understood correctly)
a new geometry copied from DOP's network result which means that if i wanted to cache out frames 1-200 and my pc crashes ,the electricity is cut off ,the PSU engulfs in flames at frame 100 i can't resume from frame 100.
With a file node i must cache out all the attributes and colliding geometries
which produces really large files.
Is there a workflow in which i could resume the caching when ever i stop it and have specific nodes to cache?
Thank you for your time!

it's a matter of preference really


If you use a file dop, set to automatic, you can set your timeline to play once only, then press play and your simulation will go ahead and cache stuff to disk as it plays.

This way, if you crash, you can also just resume this process simply by opening the file and once again pressing play.

The downside is that it will need to play through your entire dopnet, and read in the cache for all those frames before it can start the new frame where it crashed. When doing a heavy sim, this can mean a lot of wasted time. It also means that you still need to bring it into sops (and probably recache it as .bgeo since reading these files is a bit faster than importing from dops). The plus side is, it's very straightforward and simple.




You could also use a rop geometry node, like I do in the tutorials, and write out your particles (as particles) to the .bgeo format.

In the event of a crash, you'll then take that last .bgeo that was saved, and tell it to be the “SOP Path” in your particle fluid object. The plus side is, that you can now continue your simulation almost instantly because you'll be able to start simulating at frame 1. The downside is it will take a tiny bit of math to make sure that any other cached data you need is being read in at the correct frame as well as needing to make sure that your new .bgeos continue at the correct frame when you write it out to disk.

It might be a slight bit more of a hassle to resume where you left off if you cache to .bgeo, however once you've done it a couple times and know what you're doing the hassle isn't that bad, and chances are you will get it going again in less time than it would have taken for it to read in the .sim files if you were doing a really heavy sim. Another advantage is that you're already in the sop context with your .bgeos in the event that you *don't* crash.

Thank you for your immediate and explanatory reply!
Please keep up all this Great work.