So for this example, let's say there is a red circle and a blue circle. The red circle moves in a circular movement. Example here is the red circle moving by itself: https://i.imgur.com/DVwlKzN.mp4 What I want to happen is that the blue circle moves towards the red circle every frame. What I don't want is the blue circle to mimic the red circle's movement like so: https://i.imgur.com/TaOpZnA.mp4 Is there some type of clamp I can use to execute this? (I'm no expert in python, so is there an easier way to do this?)




View from top - Ortho view

An empty is placed at the center of the red circle's intended orbit and rotates. The circle is parented to this so it rotates around the empty.

A narrow and invisible plane is added and has it's pivot point set to it's upper end. This is then located at the red circle's center (SH-S) and will act a leash.

The leash is scaled in length and rotated so it's other end is at the stationary blue circle.

The blue circle is then parented to the leash choosing the "Vertex" option. (child = blue circle)

The leash's two end-vertices (at the blue circle) are then shapekeyed to shrink the leash over the same number of frames (minus a few) as it takes the red circle to make one orbit. You can have this happen (the intercept) much sooner or over several orbits if you wish.

When played the red circle does it's orbit and the leash is forced to follow and rotate with it. At the same time shapekeys are shrinking it's length, automatically making it close in on the red circle.

Chase on leash

By adjusting the leash's shape key F curves in the Graph editor, the nature of the intercept can be varied to suit.

leash adjusted through f-curves


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