Suggestions for working with 4K comps - Can I import at 4k, resize to 1080p and then re-export to 4K

[PetrolMOG]

I appologize if this question has been addressed elsewhere. I'm guessing it has and I'm just searching incorrectly, as I keep finding results that are just to the side of what I'm looking for.

In sum, I have 4k comps that need to be animated (30 of them in total). I'm using a variety of artists to assist with this project. The challenge I'm encountering is that at the 4k size, most everyones machines are being slowed down quite a bit and it's taking a long time to animate and render.

My question is as follows. Can I import my psds into after effects at the 4k dimensions, use a null object to resize all my layers to 50 percent so I can work on it at 1080p, then take my finished comp at 1080p and bring it into a new 4k comp and resize it 200%.

On the surface it seems like it should potentially work given the source assets have 4k worth of information. However, I ask because I'm not entirely clear on the ramifications of this approach or if I'm making some false assumptions. Open to other suggestions if my approach is flawed. Thank you kindly.

[Mylenium]

If you scale assets, you still process the full 4k. You achieve nothing in terms of freeing up memory or other performance gains. Scaling back up a nested composition without quality loss can be done in such a scenario could be done by enabling collapse transformations/ continuous rasterization, as that's one of its oft-forgotten uses, too, but there's a ton of potential pitfalls, since it only applies to the native transforms, could interfere with 3D, masking and other continuous rasterization as is well-documented plus all effects would have to support it elegantly, which isn't even the case, beginning with the fact that most effects use absolute pixel values and in this mess of down- and up-scaling you'd waste a lot of time adjusting values over and over to get the look you want. So from a practical viewpoint your idea has little or no merit at all. The conditions under which it would work are too specific. It would just be a mostly terrible workflow otherwise. So instead focus on optimizing that in otehr ways wherever you can - use placeholders and proxies, use stills as temp footage instead of 4k where possible, convert e.g. processing intensive source formats liek RAW or EXR to more friendly other formats, work in 8bpc and only switch to higher bit depths for final color tweaking and such and of course optimize your hardware setup where possible in terms of cache management and hardware acceleration.

Mylenium

[PetrolMOG]

Thanks Mylenium, appreciate the reply and insights. I had some concerns that resizing the assets wouldn't result in performance gains, but wasn't certain. Thanks for confirming. I hadn't considered the implications it would have on filters and plug-ins. Appreciate the suggestions to try an optimize performance. Thanks again for taking the time to provide some insights.

[Rick Gerard]

The best suggestion I can give you for working efficiently with 4K comps is to set the Comp Resolution to Auto and keep the comp Magnification Ratio to 50% or less when checking the comp for timing and action. It is a good idea only to use full resolution previews to check a few hero frames to ensure the critical parts are working before you send them to be rendered. That's the same way animators have worked for more than 100 years. Pencil tests first, then a few frames with full Ink and Paint, then the whole project is sent out for final "Ink and Paint" or rendering, and finally, the rendered pieces are edited using the most efficient editing tool you have (NLE like Premiere Pro).

If that workflow is good enough for Pixar and Disney, it's good enough. 

[PetrolMOG]

Thanks Rick, appreciate the suggestions. Along with rendering out more intensive sub comps as videos, will try some of these.