[Buddy Giguere]

conceptually it seems feasible, but only if I can reference the position values of the nulls over time to drive the start keyframe and end keyframe values of the motion path so the path will update as time goes on but the keys that build the path stay at frame zero and frame 20 (for example)

buuuuut, i dont know to make that happen, or if its even possible to write within AE

[Buddy Giguere]

I believe I have a similar inquiry but haven’t got the knowledge of the AE expression language to make it happen.

I am trying to use motion paths with Trapcode Particular. I have a good understanding of particular and its limitations with motion paths but… here’s where Im stuck and I think you might be able to sort me out…

Im exporting nulls for 2 objects from a c4d scene

I want the first keyframe of my motion path to be driven by the position of object #1 and the second key frame of my motion path to driven by the position of object #2

so that over time the start and end positions of the motion path are attached to the nulls of the 3D objects so that particles and be emitted between them and controlled (somewhat) dynamically

Below is my best guess at what I might be shooting for based on your script for Jonathan

newV1 = parseInt(thisComp.layer("Null 1").position);
newV2 = parseInt(thisComp.layer("Null 2").position);
v1 = valueAtTime(key(1).time);
v2 = valueAtTime(key(2).time);
{
v1 = newV1;
v2 = newv2;
}