I am using the "Responsive Design - Time" functionality for the first time in After Effects and unless I'm misunderstanding the functionality, trimming, rather than time stretching, appears to be broken right now.

I have a composition that contains a video clip that is replaceable via the essential graphics panel. The composition has a protected intro and outro. In the nested composition, I need to be able to extend the composition length via trimming, rather than stretching, in order to preserve the speed of the replaceable video clip contained within it.

According to the help page for the responsive design - time feature, "To trim the in or out point of the layer instead of time-stretching, hold the Option (macOS) or Alt (Windows) key and drag the in and out points."

But when I attempt to lengthen the composition while holding alt, After Effects does not let me. Oddly I can adjust the positions and lengths of the protected portions of the composition by holding alt and dragging them, but I cannot actually figure out if this is affecting anything.

Is this a bug, or am I misunderstanding the functionality here?

Thanks!

I am doing a course on Adobe After Effects and I'm following the instructor exactly... somehow since the release of the course Adobe has found a way to break their program I guess. I am importing a .ai file and somehow the composition is allowing one 1 frame instances of the items. I cannot, as the instructor does, simply drag the layer's objects to have a longer duration. So I am not able to animate the things. After Effects, you have one job right now, which is to be able to take the images and make them have durations longer than 1 frame, and you cannot do it? please help...

For example if you were to use the Point Control in animation you might set it near the knee of the puppet. Then move the knee with the Point Control. However you move the Puppet to another place in the composition the point control would currently stay locked and not move with the puppet. It would still control the knee but it wouldn't be visibly near the knee as it was before. This optional non-fixed position would give the object a hidden AnchorPoint/parenting that meant the the GUI for point control would move with the puppet but values not change until directly interacted with. Another option would be to allow the point control GUI to still be visible when its written expression contains "Value" (self-referential value) so that a user could use expressions to write this feature in themselves and still be able to see the GUI for point control. Currently GUI disappears when an expression is applied even if the expression is just "Value" a.k.a just referring to its own value.

When using a layer that has been copied and pasted into a comp -- in my case, from one comp into another, or from a Premiere timeline into an After Effects comp -- the keyframes become "locked". They aren't marked as locked, but they can't be selected, moved, or manipulated in the Curve Editor. They can be changed by moving the playhead over the keyframe and adjusting the parameter under the Layer Controls, but only then. The exact same assets when dragged into a comp from the Project panel do not have this issue, and this issue is repeatable and constant for me.

Edit to add: version 18.2.1 build 8. Windows machine. This issue is sometimes but not always is accompanied by visual glitches (especially in Graph Editor -- panel pieces disappear to blackness), crashes, and or various errors, particularly "Attempt to get an item address from a position outside of list length (27::15)"

The Offset filter is broken, and has been broken for a very long time. Here's what I wrote about it on creativecow.com back in 2013:

"This filter has been buggy for a while. It seems there’s a “magic line” of approximately 32,769, positive or negative, beyond which the Shift Center To parameter fails to work. I’m in a 1920×1080 comp, with a same-sized Photoshop file, rendering at Full quality. Set keyframes at 40,000×540 and -40,000×540. There will be no movement until the Shift Center To value crosses that 32,769 line. Then it will animate, until it reaches -32,769, at which point it freezes again."

This seems to still be 100% true. Note that you will get PREVIEWS with values beyond that "magic" number, but it won't render.