Rendering in After Effects

[Mutedblaze]

I'm rendering a pretty large project in After Effects CS3. However, whenever i render using full quality i get an error that disrupts the process. I'm rendering the project uncompressed and i've tried both the lagarith and AE default codec.
After Effects error: unable to allocate space for a 16608 x 19941 image buffer.
You may be experiencing fragmentation. In the Memory & Cache Preferences dialog box, try decreasing the maximum RAM cache size value and selecting the enable disk cache option, increasing maximum memory usage, or both.

I know why this occurs. Some of my scenes are very complex and use relatively large "motion tile" effects. However, reducing these effects is not an option so i was hoping someone knew a way to fix this. I'm able to render the project in half quality, but of course I need it at full quality. I've also tried the suggestion that the error message gives me, but i got confused and may have done it incorrectly. So anyone, who has had this problem before or happens to know how to fix it, PLEASE HELP!

[Zarxrax]

After effects is running into memory issues because your scene is too complex. Are you using any exceptionally large resolution images or layers in your video?
If you have multiprocessing turned on in the preferences, try disabling that and see if it helps.
If you have many layers onscreen at once, you could try prerendering a video of some of them, then import it back into your timeline in place of the original layers.

[BasharOfTheAges]

If that fails try getting more RAM on the system if that's an option.

[blabbler]

generally there are a couple of ways to get around this. the first thing i would suggest is always render out image sequences, it's silly to render video out of ae in most circumstances.

to your specific problem, if you hold shift and click edit>preferences you will get the 'secret preferences' tab (in cs3&4 anyway). in here you can set "purge cache every xx frames". i wouldn't tick any of the boxes though.

try purging every 20 to start with. the lower the number the more likely you are to avoid memory errors, but the longer the render will take.

anyway, if you were rendering an image sequence, you could just pick up and continue rendering from the last good frame in the sequence

[Mutedblaze]

After some tweaking, i managed to get blabbler's idea to work. Never knew about that secret tab. I'm sure prerendering would work too, but that would have taken longer to do. I used a couple of high resolution images, but it seemed to have a much harder time rendering out some complicated motion graphics. Thanks a lot for the quick help.
I have a follow up question though. I'm using 4 GB of RAM on a 64 bit OS, but by default AE uses a maximum RAM cache size of 60%. I thought i remember reading on creative cow that increasing this value could have negative effects, but i can't remember for certain or if i just made that up. Do you know if increasing it could help or speed up renders?

[blabbler]

increasing the ram preview cache size only allows you to store more preview frames in memory. how useful this is depends on the nature of your project. with motion graphics stuff where an object may be on screen most of the sequence, if you were to make any changes to that object, all subsequent frames would need to be rendered again. So even though the ram cache may have been holding most of the frames from your last preview, almost all frames would probably be discarded every time you change a parameter.
also, if you increase ram given over to previews, you take it away from the render engine.

leave it at 60/120, it's probably managed dynamically anyway.

[Mutedblaze]

Thank you. That was a lot of help!