What is faster? Time remapping or valueAtTime?

[Oleg Pirogov]

So, I’ve made some trim path animation and two comps:
Comp 1: valueAtTime(time-30) for trim path
Comp 2: precomped the layer and shifted both Time Remaping keyframes 30 sec forward.

Render time:
Comp 1: 1:42, 1:41
Comp 2: 0:49, 0:48

So my conclusion would be: WOW, expressions seem to be much slower than time remapping when I expected it to be the other way around.

[Alex Printz]

yes, time remapping will be faster as Oleg showed.

It has to do with how expressions run and how after effects renders; every time an expression is calling another value outside of itself to come in, it requires that property to be calculated prior to coming in. (despite already having been rendered and cached, because properties are not cached across frames, only the visual data of the frame!)

So the first 30 seconds of frames are calculated normally, then after that all frames are going to go back and recalculate the time-30s value of the trim path, then bring them into themselves, then finish calculating their own trim path.

Precomping, on the other hand, is how the frame is rendered. After effects ALWAYS renders all precomps prior to all other calculations to make the frame, and then when it it is ready it pulls that data back in; I think it is somehow remembering the previously-rendered precomp visual data and simply plopping that down, but I’m not entirely sure.

The AE render engine is a weird ad-hoc’d system that added content and processes over years that renders in passes that aren’t obvious; I’ve been spending some time trying to learn it, but there’s a lot to be desired on the documentation end.

Alex Printz
Mograph Designer

[Andrei Popa]

Thank you guys. This is very helpful to me.

Andrei
My Envato portfolio.