Say you’re using After Effects to animate five balls flying into a wall and bouncing off. Normally, you’d have to keyframe the instance of impact on an exact frame, before changing the direction of the ball’s position path to bounce off… which wouldn’t really have any kind of qualitative disadvantage if it was just one ball. But when there’s five of them, and all of them end up having the moment of impact occur exactly on a frame, it might feel “not chaotic & organic enough”. Or just plain unrealistic if it’s a visual effects shot… if you were to shoot video of five baseballs being thrown against a brick wall, only maybe one or two would have the concise moment of impact occur exactly during a video frame. For most of them, there’d be a slur of motion blur denoting that the impact was occurring either slightly before or after an exact frame. If the balls were composited in and all had the moment of impact synch exactly to frames, then it can kinda read subconsciously as synthetic to the viewer.
This principle – that action does not naturally unfold synchronized perfectly to the occurrence of a particular framerate – can easily be applied to animation, if your project has need for such a thing. I totally just scored major snob-dawg points with that last sentence.
- For sake of example, say you’re using After Effects. Put your animated layers in a precomp that has triple the framerate as your main comp… ie. if your main comp is 29.97 fps, then make your precomp 89.91 fps.
- Animate the layers moving/colliding/bouncing/etc in the tripled (89.91) framerate precomp.
- In your main comp, you should see that the moments of change/impact/etc are sometimes occurring at a moment in time that’s between discreet frames.
- Moving any keyframes in the precomp by one or two frames allows you to put those moments of impact on or off “the temporal grid” of the main comp.
- Be sure to use the phrase “temporal grid” around your coworkers to look pretentious. Err, I mean classy. Classy and sophisticated. You know, like how James Bond is.
Of course, if needed you can up the framerate of the precomp to whatever if you need more chaos/realism in the timing array of impacts.
I first came up with this when working on the project pictured below, needing smaller units of time to distribute the keyframed squares that comprise the flame movement. Since then I’ve used it on VFX-ish compositing shots for the reasons I noted above.