Thanks a lot for your input Yoan!
Your first mentioned solution sounds logical. I have two questions about it:
1. Within expressions: how do you indicate which values (either the expression- or keyframe-based) the property should adhere to? I have never applied that method before. Could you show me an example of what such an expression would look like?
2. Using that method: would it be possible to exercice control over the transition between the last ‘generated’ position value, and the new ‘set’ (keyframed) position value? The way you describe it makes it sounds as if the shape only switches between which ‘source’ the values come from (either an expression or a keyframe), but that there isn’t any interpolation between these two values. I’m hoping that it’s possible to apply different kinds of easing when switching between these sources.
Secondly: If you’re willing to elaborate on Dans solution a little bit more, which you mentioned should also work, I would really appreciate it. I can see the logic in it, but can’t wrap my head around how that would work, for I’ve also never applied sliders or slider controllers much in my AE projects.
Looking forward to your answers. Thanks a lot again! ?