Connect moving sphere with cube of another scene using a line

[sgeier]

Hi community,

I have been struggling to connect a moving sphere geometry to a cube geometry that lives in another scene. I build it this way because I needed the cube to stay static - it should not move when OrbitControls are moved.
I have everything working except the part where the line vertices are updated and connected to the other scene's geometry.
The connecting line should properly display in space originating from middle sphere to fixed cube (to right corner). The line should constantly connect.

I'd appreciate any help or pointers / ideas. This blocks me currently ;(

Thank you!!

Codesandbox:
https://codesandbox.io/s/react-three-fiber-viewcube-forked-4l0ix?file=/src/App.js