Preview is very slow I can't find what to change to fix it

[Orangegabriel]

I've just started using After Effects, and am unable to find what it is i need to change to stop that slowing down. My available is ram for this and Premier Pro is 10GB, even with pro closed it still does this. I have tried increasing the 100GB available for the max disk cache (i doubled to 200) that did not solve anything. I just would like to be able to view the changes i'm making without having to export the whole file. I tried rendering the video, to see if that would help, no change. I'm rather stumped actually. Any help is greatly appreciated. I'm on a 2013 IMac with a 3.5GHz Intel Core i7, and can give other info as needed.

[Rick Gerard · Accepted solution]

Check the User Guide. If you are new you need to spend some serious time learning the basics.

Previews are based on available resources, free ram, comp frame size, comp resolution, comp frame rate, the Preview Panel settings, and everything that is going on on every layer in your timeline. After Effects is NOT a video editing app. It specifically designed to create composites, visual effects, animations, and motion graphics you cannot create in an NLE like Premiere Pro.

You need to adopt what I call the Pencil Test, Ink - Paint workflow. Traditional animators and 3D animators like the folks that work at Pixar and Disney always set up the staging and action in a shot or short sequence by using low-resolution images or 3D models. Animators do Pencil sketches and then preview those to make sure that the timing, framing, and staging is correct.  You do that in After Effects by setting the Comp resolution to Auto, the Magnification Ratio to 50% or less, making sure motion blur is off, maybe set Fast Previews to Fast Draft, and keep all color correction, lighting, and other effects turned off. If needed set the Preview Panel to skip 1 or 2 frames but always leave the Preview Panel frame rate set to Auto. 

When you have the shot or scene working turn on the effects, add motion blur, lights, and everything else you need to finalize the shot. Set the Comp Magnification ratio to 100% and pick out a few hero frames so you can adjust the final look of the scene. If you do need to preview something, you have to be satisfied with just a few frames, because previews can take a very long time to render. I start redesigning my compositions when render times start approaching 4 or 5 minutes per frame. You read that right. 

If the pencil test is ok, and your hero frames look good, it's time to render and move on to the next comp. That's how they do it at Pixar and Disney and they have got a lot better equipment than mere humans can afford, but they don't have the time or the inclination to preview things over and over again at full resolution with full effects because even the media giants don't have that much time or money to waste.

[Orangegabriel]

Thank you very much, that makes much more sense, it is now obvious that I was looking at the application expecting it to be for a different purpose. Thank you very much once again for spending the time to eplain that!