Drawing specific lines

Hello ~
I want to draw a line where the point of contact between the plane and the sphere faces the outside of the sphere, what data do I need to get and how do I calculate it.
Thank you.

Hello :slight_smile:

There are several ways, but since you already binded a mesh (ground) on the surface normal, you could just add a child to it : Playground
(Edited materials just to have it more visible but I let you edit)