3 Replies Latest reply on Nov 22, 2009 2:14 AM by Mylenium

    After Effects and the simple 20 hour render

    Redsandro Level 1

      Hi,

       

      I have this HD scène that is about a minute in playtime. When it was done it rendered out in about 1 hour and 20 minutes on my Intel Quad Core 2.4 GHz. That seems pretty reasonable to me.

       

      I decided to add some lightwrap and edgeblur for some bad matching cg objects. For this I precomposed transformed layers so I had maybe about 20 preComps. For every preComp I added a matte layer, adjustment layer and light layer. So that's 60 layers. Note that all this is divided over about 10 parent comps (shots) so it's not all in the same comp.

       

      Anyway, don't think so much about it, it hardly changed render time in the preview. Every frame still takes about 10 seconds to show up on screen when there's no cache, which is the same as before and seens reasonable.

       

      But after the changes, render time was 20 hours!

       

      This is ridiculous. It has no crazy stuff at all. Any cg was prerendered in other software and they together didn't even take that long.

       

      I remember I had crazy render times some other time when I had a LOT of precomps. But the internal preview worked just fine then also.

       

      It made me think about After Effect's efficiency so I put my CPU monitor gadget on screen (Windows 7 Pro x64) and it shows that After Effects is only doing a half decent job!

       

      AErender.png

      You see that all cores are working. The idle start and first peek is when I loaded the project and started rendering.

       

      Two questions:

       

      Why is After Effects lazily using between 20 - 70 % of my CPU? There is clearly no HD I/O bottleneck involved, because 20 hours is enough to copy the internet as a figure of speech, and how can I force it to speed up?

       

      Can I get a detailed log or something about what is rendered and how long it takes on a per-layer basis so I can see what is the bottleneck?

        • 1. Re: After Effects and the simple 20 hour render
          Todd_Kopriva Level 8

          For general tips about speeding this up, see "Improve performance".

           

          I'm guessing that the 20 lights might have something to do with increasing your render time.

           

          That said, 20 hours is not unusual for a minute of HD material with a bunch of effects and blending and lights. I'm sure that the old-timers on this list would be happy to tell you about their weekend-long renders for SD material.

           

          > Can I get a detailed log or something about what is rendered and how long it takes on a per-layer basis so I can see what is the bottleneck?

           

          See "Information shown for current renders".

          • 2. Re: After Effects and the simple 20 hour render
            Redsandro Level 1

            Thanks for this information.

             

            Though partially misunderstood me, pherhaps I said it wrong. Sorry for that.

             

            I am not having 20 lights. This is a relatively simple 2d composition. I added lightwrap: a copy of the background over the middle- and foreground with some glow and holdout to pretend the subject fits in better.

             

            I do a lot of compositing, cg and rendering, and anyone in my shoes would agree one maybe two hours is a reasonable render time for what I am doing. The preview time remained the same or increased by a neglitable amount, but the final render time increased 10 times. That strikes me as odd to say the least.

             

            I have to examine the More Information note from "Information shown for current renders" to see if I can get per-layer rendertimes but it is not mentioned. I will check that on my next render.

            • 3. Re: After Effects and the simple 20 hour render
              Mylenium Most Valuable Participant

              Do you use MP rendering? If so, you may have created yourself a pinch by using a specifc non-MP-safe effect or output format. In essence it would go into attempting to load certain things forever in the background, then fail (without proper warnings), only to attempt the same again after a few microseconds. If this goes on forever, the only remaining procerss that actually renders (the foreground instance), would also be impaired because it needs to throw a lot of resources on managing the badly behaving BG instances....

               

              Mylenium