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To: "'After Effects Mail List'" <AE-List@media-motion.tv>
Subject: Re: VR Tools GPU/CPU VRAM limitations
Date: Fri, 22 Jun 2018 13:36:36 +0200
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Stephen van Vuuren wrote:

> I can find no useful information on:
> 	* Is there a way to force CPU rendering?
> 	* How much VRAM is required and can you use SLI to split via
multiple=20
> cards as 8+ GB VRAM cards are very expensive.
> 	* What frame sizes does the VR tools support? We have 5600 x 4200
and=20
> 8000 x 8000 - the weird part is simple projects are fine, but bring in
lots of layers, bitmaps and the errors begin.

I guess the VRAM requirements for AE are like the ones for Premiere. =
Quoting
from page 559 in The Cool Stuff in Premiere Pro:

* The approximate amount of GPU memory needed is Width*Height/13107
* An 8K video frame, 8192 =D7 4320 pixels, requires approximately 2.7 =
GB.
* Stills from a Canon EOS 5DS, 8688 =D7 5792 pixels, require =
approximately
3.84 GB, so you need a GPU with at least 4 GB video RAM.

8k x 8k requires about 4.9 GB per layer.

This is per layer, so if you blend two layers of that size, double the
required amount of VRAM to get real-time playback (with GPU-accelerated
effects only). When you run out of VRAM, you'll need to render. The
rendering will use both the GPU and the CPU, unless you choose Mercury
Software Only in Project Settings.

https://premierepro.net/coolstuff/


Brendan Wrote:
> Weirdly, we had other machines with the same graphics card and =
everything
else that couldn't.=20

If the screen resolutions were different, that could explain why this
happened. The GPU is also responsible for pushing pixels to the screen. =
One
of my clients failed to do the math, and bought lots of laptops that =
they
planned to use with two 4k monitors. They had to lower the resolution of
those monitors to HD. There wasn't enough VRAM left for AE and Premiere =
when
they used the 4k resolution.

I have not been able to find any documentation about how much VRAM is =
used
to push pixels to the screen at different screen resolutions. Has anyone
seen something like that?