"apply unary force to moving point" in order to make membrane with kangaroo. how ?

Please check the video to see what is wrong.

https://www.youtube.com/watch?v=6uEk4SGJHB4&feature=youtu.be

I would like to make a membrane as form-finding method using catenary theory of Kangaroo.

This is easy. there's no error in the movie. Kangaroo engine is working correctly.

However, as you see the title , the question is " applying force to moving point" or applying force different position bit by bit.

you can see the moving agent( red cone).

Once I ran the Kangaroo, the unary force is applied the closest vertex(point) in a grid from agent place at first. After that, the force stays to be apply at first place.

This works correctly. But this is not what I want.

It should be applied along moving agent(point).

Any solution for this ? Or it's not possible ?

Thank you.

Yohei Kanzaki.