[Manuel Moellmann]

what kind of error do you get? and what does ‘take the value of the last keyframe and continues’ mean? continues to take the value of the last keyframe? thats what usually happens if its tge last keyframe 😛

[Manuel Moellmann]

I think thats what you are basically looking for:

https://community.adobe.com/t5/after-effects-discussions/keyframe-less-position-animation-trying-to-use-multiple-interpolation-expressions-in-one-property/m-p/12462964

[Manuel Moellmann]

hey, one easy thing to do that i use to use a lot of times, is to remap a simple kf animation to in and outpoint.

something like this:

valueAtTime(key(1).time+time-inPoint) else if(effect("Checkbox Control")("Checkbox") > 0){ valueAtTime(key(1).time+outPoint-time)} else value 

here a little demo to show what I actually mean 😛

https://docs.google.com/uc?export=&id=1pVEv77rk1DAcwINbuiHCuaNih_k6sBpl

Ofcourse the expression itself is kind of basic, but its easy to use for all kind of properties.