why is AE rendering with RAM – and what can i do when AE stops rendering because of RAM capacity overload?

[Christian Tanner]

thanx dave!

…but apparently i haven’t explained my problem well enough:

in the render cues heading (upper left corner of the window) AE states “start render time”, “total time elapsed” etc… plus “RAM” used. i now was wondering (when i add stuff to my render que that is) why AE would use RAM to render.

so – unless adding stuff to the render que via “composition > add to render que” isn’t a render but a ram preview… i shall still be looking for an answer 🙂

my question by the way, is not just because of my problem – but because i was under the impression that rendering only uses the engines processor, nothing else. is that correct at all?

christian

[Christian Tanner]

thanx again dave!

the original question still remains though:

why does AE stop rendering (or in other words, output a file that hasn’t been rendered all the way) when that RAM gets used up?
and what can i do to prevent that?
would it help to pre-compose nested comps? is there another way? what’s other AE users procedure on that?

i get the point of what you said about AE using RAM for very large comps etc. my comp is normal pal size. lots of nested comps though. motion blur as well. but still – AE should render that just slower, not stopping in the middle of the render, right?

thanx again!
christian

[Darby Edelen]

[christian tanner] “i now was wondering (when i add stuff to my render que that is) why AE would use RAM to render. “

I’m going to use a lame analogy:

RAM = Short Term Memory

When After Effects renders things it tries to remember as much as it can about the layers in the rendering composition from frame to frame (this is called the image cache). The benefit is that if nothing is changing about a layer, AE can simply recall the layer’s last state from its Short Term Memory (RAM) without actually having to render anything. As AE remembers more and more about the layers in your composition it uses more and more RAM, however you can set a limit to the amount of RAM available for AE in the Preferences > Memory & Cache preferences window. Look for the field titled “Maximum RAM Cache Size,” generally a value between 40-60% works well here (if the value is too high then AE can suffer from memory fragmentation, if it’s too low then your renders will take much longer as AE can’t ‘remember’ as much).

Darby Edelen
Designer
Left Coast Digital
Santa Cruz, CA

[Darby Edelen]

[christian tanner] “why does AE stop rendering (or in other words, output a file that hasn’t been rendered all the way) when that RAM gets used up? “

How are you sending things to the render queue?

Darby Edelen
Designer
Left Coast Digital
Santa Cruz, CA

[David Bogie]

q[tanner] “i was wondering why after effect uses RAM to render. (says so on the render que info – where it also shows the RAM’s capacity).

plus: if that RAM opperates at its full capacity – after effects stops rendering. “

I was avoiding trying to answer this till I had a chance to figure out what the question really was.
when i send something to the Render Queue, I do not see RAM in the render queue info. But I use composition>Make Movie to get to the Render Queue.

bogiesan

This is my standard sigfile so do not take it personally: “For crying out loud, read the freakin’ manual.”

[Christian Tanner]

hey darby!

i send things to the render que via the menu “composition” then “add to render que” – or by using the short cut ctrl+shift+\

christian

[Christian Tanner]

hey david!

there isn’t an obtion to post a screen shot here is there?
anyways: by using the path “composition” and then “making movie” i think you might not be able to use all the render ques obtions – at least that was what AE was telling me with a funny pop-up when i used that obtion the first time.

@darby: thanx for the input man. that made perfectly sense. apart from the RAM fragmenting thingy of course, if the cach is set too high in the preferences…

ah – and let me just stress that last question about the nested comps one more time…
is anyone pre-composing nested comps in order to save time/maximise system performance?

christian

[Christian Tanner]

i forgot…

thanx dave for that “purge ram tip” – i might just try that sometimes…

christian

[Darby Edelen]

[christian tanner] “ah – and let me just stress that last question about the nested comps one more time…
is anyone pre-composing nested comps in order to save time/maximise system performance? “

It will only help performance if you pre-render the pre-comps, which is sometimes good to do if you know there won’t be changes to the pre-comp… but it obviously limits the changes you can make to that footage.

I’m curious about the phenomenon you describe of the render ending. Does AE give you an error? Does it say it completed the render successfully? The % RAM used should never reach 100% (unless you have terribly bad Memory & Cache settings)…

Darby Edelen
Designer
Left Coast Digital
Santa Cruz, CA

[Christian Tanner]

hey darby!

my RAM’s pretty crappy: 2G. (that planed upgrade is long overdue…)
my max RAM cache size is 60%
maximum memory usage is 120%

apparently still the default values 🙂

and no – AE doesn’t give me an error.

ah, and by the way – i get the RAM-fragmentation now. It’s the same as with a hard drive – doh – simple as that…

i guess i leave it at that and will pre-render my pre-comps if that problem keeps reoccuring. or i might try davids idea.

christian