Compositing large renders in After Effects

#1

I’ve been struggling with a 7200x4800px 32-bit EXR with all Vray channels in the single file. Total size is ~800MB and it slows AE CS4 to a halt on my Mac Pro quad2.66 with 7gb ram.

I’m using extractor to chop up the channels within AE. I’ve realized that extracting the Z channel won’t work with lens blur, even if I drop the project to 16/8bit. I’m wondering if extracting channels is pulling to much memory and if it’s better off to break up the EXR into separate files when working this large.

As far as AE settings, I’ve tried enabling multiprocessors, messing around with the memory to leave for other apps and enabling the disk cache. Right now I’ve got a 15gb cache available and I can’t manage to send out a full size EXR or TIFF for the life of me. I’ve tried the ‘save to anywhere except your boot drive’ trick and it hasn’t worked so far for my final comp.

#2

The only way to handle this in AE is to use a proxy. You can create a low re proxy in photoshop and reference it or you can try to render out a proxy out of AE but with something that size it will most likely fail. Because AE does not have a scanline render like Nuke or other apps it layers on everything in the frame and runs out of memory. I have huge problems with this getting memory buffer underrun error all the time or something to that effect. Once you set up your scene and do all your comping and effects the proxy will be replaced at rendertime.

I would do a test before all your work to make sure that AE can still handle it when its changed to a proxy.

Rob

#3

Thanks Rob. I ended up getting it out by breaking the comp in half for that job. AE with an 800MB file was a nightmare to say the least. I’ll look into Nuke.

As far as the channeled EXRs - would comping one channeled EXR use the same amount of memory as having those channels separated into different files?

#4

Im at work so I cant check it out but EXR has a fairly good compression, unlike something like a tiff which has not ad takes into account every layer and every pixel. HD res RGBA tiff = 16M or 4096K / layer.

So I think if you need those layers anyways it is not going to make a difference if it is in seperate files or in the same one. I know that in the memory settings you have to have the max memory set over 100% and the other setting in there deals with the size of the chunks it allocates for memory. so you can set that one lower like 20-30% chunck so you dont max out so quickly.

its like you can set it higer if you know you wont run out and AE will spead through the render, but if you need it to be lie a small tank and at least try to make it through make set that other setting a bit lower, it will take longer to render but may not crash.

Your best bet really if you want to use AE is to look into using proxy files. Its still going to be more manageable then splitting up the files, frames or channels. Only deals with the large file at render time so you do have to worry about it.

…Or better yet changing to nuke for the big stuff. I still use AE for motion graphics and quick effects. Ive used 30000X20000 matte painting with nuke and had no problems…it will get slower but can handle the big stuff for sure.

Rob

#5

Thanks Rob. It’s too bad I didn’t realize the limitations of AE until I was in the final stages of comping this job. Oh well.

#6

i had some 6k images scanned from some paintings . and i was suppose to color correct them etc … but AE wouldnt even load them up . i got so F’n pissed off . AE is like my wife i love that bitch to death … but i had to cheat on her when i found she would only do some dirty things and not all
my mistress now is got fusion 6 … but i allways go home to my wife ( AE ) lol

#7

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