Moving the last keyframe in time using expressiosn

[Adam Greenberg]

this has been discussed before, here is a link until someone potentially rings in with a more concise answer,

https://community.adobe.com/t5/after-effects-discussions/link-a-keyframe-to-slider-control-without-affecting-other-keyframes/td-p/9887407

[Dan Ebberts]

You can’t really move keyframes with expressions, but you can simulate it with something like this (assumes there are only 2 keyframes):

t1 = key(1).time;
t2 = key(2).time;
tNew = effect("Slider Control")("Slider");
t = linear(time,t1,tNew,t1,t2);
valueAtTime(t)

[Filip Vandueren]

If you want to keep the easing you already have set up between your keyframes and don’t want it to default to the linear() or ease() functions:

(this example has 3 keyframes, and a slider controls how long the animation should last after key#2, disregarding the actual timing of keyframe#3

time_2 = key(2).time;
time_3 = time_2 + Math.max(0,effect("Slider Control")("Slider").value);
if (time < time_2) {
    value;
} else {
    t=linear(time,time_2, time_3, time_2, key(3).time);
    valueAtTime(t);
}

[Ivan de Wolf]

WOW thank you everyone for the fast response! It works perfectly! <3