Linking keyframes possible?
by Taige Jensen on Jan 3, 2012 at 5:03:53 pm
I'm creating AE "templates" that are sent to other producers, where lots of the work is pre-produced, you just drop in images, and then drag key-frames to adjust timing and things, and it would be so helpful and great if there was a way to link key frames, so when you move one keyframe, it also moved the one its linked (grouped) to.
I feel like this would be such a handy feature that it must exist, but I can't find it.
Re: Linking keyframes possible? by ben g unguren on Jan 3, 2012 at 10:56:53 pm
Command+Opt+A selects all visible keyframes; holding the option key while dragging the outermost keyframe of a selected set does a proportionate scale of the selected keyframe set (I like to call it "accordion scaling").
If you want a single keyframe to retime everything, you can pre-comp the animation, then use time remapping to tweak the group animation to your heart's delight. That's so easy to do it's sickening. You can even do it with 3D layers if you collapse transformations.
There is also a way to do this with expressions, but in most cases it's too complicated to bother with. I've done it in the past when working with 3D motion tracked footage -- I'll track the footage in Syntheyes then export a 3D camera and other 3D nulls into AE. Later, I end up time remapping my footage and need the camera/nulls to speed up/slow down to match the remapped footage, so other 3D elements match with the base footage. (See how complicated it sounds, before we even start writing expressions?) Here's how I do it with the camera, for instance: First, I add Time Remapping to the base footage. Second, I make a copy of the camera -- name one "REF_CAMERA" and the other "REMAPPED_CAMERA." Third, for all animated values of the "REMAPPED_CAMERA" (we'll use Position for the example) I create an expression that, in essence, links the value of the Position of the REF_CAMERA at the Time value represented by the remapping done in the base footage (using "value_at_time"). I don't have the expressions in front of me, but it does take a little while to set it all up. Once you're finished, however, it's pretty cool -- the only thing you change is the time-remapping keyframes for your video (or a precomped layer, or whatever works for you) and a bunch of animated layers are updated accordingly.
But, as I said, in most cases this last option is a complete waste of time.