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Afterglow
09-17-2009, 09:41 AM
I am at the end of finishing an animation, rendering out all the passes. One of these is an explosion of dust, done with particles.

This is my first time trying to 'cache' particles as I heard it saves the animation and you can scrub through a lot quicker, etc.

However, since caching these particles, it has slowed it down. It seems that once a cache file has been created, it scrubs across at a very slow rate, compared to normally when it runs very fast.

The problem I have is trying to batch render this out. I have rendered a previous explosion fine (did not cache) but there maybe a problem with the amount of particles in this one, as it crashes my machine. I thought that caching the animation would work in a way that I could continue rendering where the machine crashed, but when it is cached, if I go to a part in the timeline, the particles are not there, only when I scrub up to it from the start of the explosion.

Basically, If anyone knows a good tutorial on caching particles so that it actually SAVES the animation, it would be greatly appreciated. I have been stuck on this ****ing thing for 2 months!!!

Thankyou!

-Josh
redpawFX
09-17-2009, 04:13 PM
Its hard to say what is exactly happening with your file. but guaranteed if you're scrubbing thru without cache, its not goign to be the same particle result as if you scrubbed with a cache. and you can't scrub backwards and have it update. thats what cache is mainly for.

Disk cache (assuming regular particles?) as PDC files is usually pretty fast. However if you're pulling the cache off a network that happens to be pretty loaded up it may slow you down quite a bit.

how many particles are you talking about here? 100,000+? how big are your individual pdc files?
If it is network stored, maybe try copying the project locally before you render.

on that same issue. you have to make sure when using cached particles/fluids etc.. to set your render job up to use the proper project file and workspace so that the render knows where to look for your particles..

hope this helps..
efecto
09-17-2009, 08:48 PM
you have "use particle disk cache" turned on in the cache settings right?
Afterglow
09-18-2009, 01:49 AM
All rendering locally, and the project file is setup. No avail...

Cache disk particles is on. As soon as I turn it off, it seems to scrub through much faster. Just not sure why I cant navigate to a frame, and the particles are in mid-explosion. Isnt that what its supposed to do?

Any more ideas would be sweeeett. Thanks.
EightBit
09-18-2009, 02:33 PM
I don't know the whole answer to your problem, but the reason that you can't navigate to a frame without a cache is that the particles must be calculated from the first frame - with the state of the simulation at any given frame built on all the previous frames. The cache is file or set of files that contain all this info - I think its just the numbers of particles and positions, because you can make some changes to the character of the particles without having to rebuild the cache. When cache is enabled, the particle system doesn't calculate the particles, it reads the info from disk. If you need to start with many particles, you can set an initial state and then that part of the calculation doesn't need to be repeated each time.
I'd recommend that you delete the particle cache and rebuild it. You might also lookup a quick tutorial on particles that includes an explanation of the proper use of caching.
Are you using nParticles?
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09-18-2009, 02:33 PM
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