Rolling cache to avoid disk space limits

Hi all,

I just started playing with Eddy again (finally), trying to dump some dry ice on 1000 frames of horizontal billowing cloth. I approached this by using a Box emitter and letting that emit onto the cloth for a frame, then just letting the smoke spread across until it thins out naturally. Once it’s spread out enough, I use that cache frame in a new element node set to “use initial state cache” for the actual shot duration of 1000 frames.
It’s becoming clear that I need to pre-cache a fair amount of frames to get a good initial state (spread out evenly and thin).
This of course will take a shit load of dick space, even though I’m only after one frame to initialise my final sim.
So I was wondering if it would be a clever feature to have the cache node only cache n amount of frames, then start deleting the oldest ones to guarantee you won’t run out of disk space even if you need to run the sim for a long time.
Obviously the trade off would be that you sim too long and all useful caches are gone, but cool features always come with gotchas :slight_smile:

Any thoughts on this?

Cheers,
frank

Hi Frank,

It sounds like you want to have a lot of pre-roll and only start caching from a certain frame onward. This is currently supported. On the E_Cache node you have a “Use Frame Range” toggle which you can turn on and then define a frame range which will control when to write a cache to disk. If you set the min frame to 100 and execute the node from 1, it will only write a cache starting from frame 100.

This is how you can do a long runup without wasting space writing out frames you will never use.

Cheers,
–Ronnie

1 Like

Ah, obviously misinterpreted those frame range controls. Perfect, thanks.