Relative animations

Report · Mar 16, 2022

One underestimated game changing feature would be a toggle to change a keyframed position or rotation animation from absolute values (ie. from positon XY to positon XY on this comp) to relative values (ie. from X0,Y0 to X200,Y100 from this objects center).

This would enable self made animation presets to be a key component for animators. And would simplify some null workflows.

Report · May 12, 2022

I think I get what you're saying, but that's the way AE already works. Position values are by definition relative to something, some reference point, some coordinate space or other, and Nulls are a necessary (and the most flexible) way to let us place and re-use animations.

Sure, you can animate something (a ball bouncing, say) from [0,0], but now you've got lots of Position keyframes, how do you then tell AE where you want the ball to be bouncing in the frame? You can't use the Position parameter any more as that's where your animation is.

If it bothers you that every new layer you drop into a comp starts with its position set to something other than [0,0], that's because AE is helpfully centering the layer within the comp for you. But you don't have to leave it there if you don't want to:

Create a comp and drop a solid in, then set its position to [0,0].
Now you can animate the object to move, and any animation you create is relative to [0,0] - the centre of the unanimated layer.
You can now copy that layer into any other comp, and the animation will work exactly the same in them. The animations are all based around [0,0] - where the centre of the layer was before it was animated.

They're not in the centre of the composition, though: the layers' animations are all based around the top left of any compositions you copy them into, and that may well not be what you want. Chances are you want the layer to do its animation, but do it somewhere else within the composition's frame.

So you need another Position parameter, a way to tell AE "I want this layer and its animation to start over here, rather than the top left corner"..? That's what Nulls are for. You put the Null where you want the layer to do its thing, link the layer to the Null (holding Shift while you do it so the layer moves to the Null). Now you still have your layer animation, but the Null gives you an extra position control so you have a way to say where in the comp it happens.

Nulls are a necessary part of life precisely because all coordinates are relative. All animations are relative to something, some reference point.

Adobe could have set things up so each layer has two position controls: one to animate local stuff (the bounce of the ball) and another to say where in the comp this particular ball needs to be, but Nulls are just more flexible. Every animation package out there has a similar way of working, though they may call them different things; Nulls, Emptys, Locators, Groups - they're all ways of offsetting things, so you can keep local animation of the thing separate from where to position the thing.

If having lots of Null layers clogging up your timeline bothers you, you can turn on the "Shy" switch on them, then hide and unhide them all in one go with the "Hide Shy layers" switch up above:

(Anchor Points: okaaaay, there is an alternative approach: every layer as an Anchor Point parameter to tell AE where you think a layer's centre should be, and AE sets it automatically for you when you add a layer to a comp. It acts as a position offset for the layer. You could animate that instead of the Position to get your ball bouncing, and that'd leave your Position parameters free for placing the ball where you want it in the comp, but that's likely to get confusing for a number of reasons, and is not a sensible approach for most things. But hey, mentioning it for completeness. Use Nulls 🙂