Simulation sizes

[Filip Kaczorek]

Can someone please clarify what's the connection/difference between the:
- up to simulation size at the general tab in grid settings
- up to rendering size at the general tab in grid settings
- memory used / cached during simulation - in the simulation window
- and final frame cache file on HDD

Also which of these do I have to accommodate with RAM - I mean which of these tells me how much RAM I need and if I don't the simulation will crash?

- also what is the difference between a snapshot and "ability to stop/continue"

[Jordan]

The up to sim size is how much ram fumefx would use to sim if it was using all the voxels (ie, with adaptive grid off or with the adaptive grid filling the whole fume grid)
Render size is how much ram needed to render a full grid (will depend on how many channels you save out, eg just smoke will be smaller than smoke and fire and fuel etc.) Handy if you have say a 16gig Sim machine but need to render on 20x 4gig machines or something.
Memory used is just what it is! Dependent on voxel size mainly.
Size on disk will depend on how many channels you save out and and grid size will go to about x10 if you turn on fluid mapping.

Snapshot will just dump a full sim file saving everything needed to continue a sim or do an initial state every 10 frames (or what ever you specify). Dont use it much so could be wrong. Never had much luck with snapshots so have just turned it off to save time and space.
Ability to continue will let you dump one of these files when you press "Stop" rather than cancel while you are simming and then you can change settings and continue if you want.

Look at the "up to simulation size" for your ram usage, dont forget to accommodate for ram used by the OS and Max. If I set it to about 3000 I find it will stay under 4gig OK.

[Filip Kaczorek]

The up to sim size is how much ram fumefx would use to sim if it was using all the voxels (ie, with adaptive grid off or with the adaptive grid filling the whole fume grid)

That's the thing - I set up a simulation that says "up to 80 GB", the adaptive grid fills out the whole fume grid after a couple of frames but the simulation memory usage stays well below my 8GB RAM and it simulates quite fast.

So I was wondering that maybe the up to memory usage was something like per Frame*number of simulation frames.
Espesially that the sim data on hdd for the entire simulation range took about 30GB which is closer

But then I was lost with the rendering "up to" )

I also did some test where I maxed out (99%) my RAM in the simulation window and Task Manager - Fume still didn't crash but the simulation really slowed down (like 10 to 20 times).

I'm trying to find out how to tell that the simulation will crash or stop before I set it up for the weekend ang go home

[Jordan]

So your grid size was about 1300x1300x1300??
If you are running 64bit OS and 64bit max you shouldnt really ever crash, just that if you go into HDD swap then sims will be like 10x to 100x slower!!
Just try to say under the ram you have.

[Filip Kaczorek]

1800x1700x600
I'm working on a huge crash scene and I want small whisps following particles so I can't get away with a lowres cage

[Chris Pember]

if you have access to krakatoa, you could always set up a pflow or tp particle system, drive it with fume sim, then dump out a pile of partitions.. i tend to do that a lot here.. works well for wispy stuff without having to deal with ginormous sims.

c[p]