“option” + drag to duplicate keyframes and layers

Look at Cinema. Time stretch as an actual box. Then option is no longer needed for that so opt+drag can duplicate keyframes. This would also allow us to reverse a group of keys properly.

The behavior definitely sounds useful, and any time we can achieve consistency with other Adobe apps is always nice.

I use alt-dragging (to "accordion" keys) relatively frequently (and also use ctrl+alt+click to toggle Hold fairly frequently), but I feel like I might agree with Steve that Ctrl+Alt+Click might be negotiable. That said, this probably means I'm suggesting changing TWO existing behaviors (alt+drag becomes Duplicate, ctrl+alt+drag becomes "accordion"), which sounds insane.

As I was typing this, I wonder if I've perhaps stumbled onto something - maybe I'm crazy, but would it be possible to hold the D key (for, you know, *D*uplicate) to accomplish this? While the key is different, the behavior is in line with other Adobe apps. As AE is already such a complex program, users are used to getting similar behaviors, but with different hotkeys... (It's probably not possible to separate this from the existing functionality of D to "Scroll to current time," is it? Would this be an easier change to swallow?)

+1 for this needing to work for keys on multiple layers at once.

+1 for being able to add another modifier key to reverse the copied keys.

+1 for being able to force the keys to sit on exact frames.

+1 for a bounding box that allows you to both see what you're doing and intuitively manipulate the group of keys (similar to behavior within the Graph Editor).

I wouldn't mind this.

I'm used to copy-paste but I wouldn't bother changing this for a new feature which is also useful.

Side note. There needs to be a way to put those time stretched keys back on actual frames if you must keep doing that. It causes a lot of problems down the line.

What about a bounding box for the keyframes? That replicates a typical and obvious use case, communicates a clear mode, and allows for even more scaling options (center based).

The bounding box could be constant or a separate mode triggered by a command (Cmd T for transform?). Yes if you’re a constant opt dragger, it’s an extra step but you get more flexibility.

Would it be weird if Opt+Drag worked for duplicating a single keyframe, but when used for multiple keys you would hold Opt and drag from in between keys and a new, subtle UI element would pop up indicating that there will be a duplicate created? Something subtle like th plus icon that gets added to a folder when duplicating in Explorer and Finder.
Or maybe the selected keys would be highlighted in a new way, but only while Opt is held and the mouse is within the bounds of the selects keys, but not over one of them.

I am someone who uses the time stretch option with some frequency and I'd be perfectly fine if that moved to control/command instead of alt/opt. Sure, it'll be annoying for a bit, but I'll get used to it. And, heck, roving keyframes (ctrl+clicking) kinda feel like time stretching in a way, so it fits pretty well.
Copying keyframes while holding alt is something I can totally get behind - especially if it works on multiple layers simultaneously.

Why not command-option? Is that used?

In my view, preferences to allow users to disable new behaviours are usually a good idea (see the backlash to the new Home button, for example). Disrupting muscle memory isn't great, but it isn't the end of the world, especially if it's something less than fundamental and adds a really useful new feature.

I use Option-drag to scale keyframes quite often. Looking at current modifier combo's on keyframes, I think the one I'd miss the least is Cmd/Ctrl + Option clicking (which currently toggles Hold interpolation). Personally, I'd add a new key command for Toggle Hold Keyframe - HH. We're all using TT and UU all the time, why not use a few more double-tap keys? Then have the Cmd/Ctrl + Option drag do the duplicating. Or if people want the duplicate with Option-drag, use Cmd + Option drag for the scaling.

I also want to say that adding an option to drag keyframes to duplicate them 1. Needs to work with keyframes on multiple layers, and 2. Is not sufficient on it's own - we also need the ability to copy and paste keyframes from multiple layers with keyboard commands. Because dragging is not always easy to do with precision, for example if working in long duration comps on a smaller monitor. Pasting multiple layer keyframes to the CTI is, I would say, more important than being able to drag-duplicate them. And it should not require any more than the standard Cmd-C and Cmd-V. I was teaching 3rd year students recently and they find the existing behaviour (layers copying and pasting) bizarre - it goes against the expectations that the rest of AE's behaviours (which are more contextual, based on selection) actually engender.

Personally I prefer it as/is