i tried with rectangle than added object (circle in my case) comp them and add feedback.
but only rectangle is affected by feedback
Looks like a feedback loop like here: https://www.youtube.com/watch?v=yBbgkk5cGyA (but directed inwards).
The influence of the 3d body is probably made by a added/overlayed/over/under of the edges of the body.
Try to grab the edges with the edgeTOP directly after the render (or your circle) and pipe that into the feedback too.
Should do the trick…