There is one Complex answer.
The core idea is using Camera > Z Clip options
If you finished the 3D stroke Settting, then duplicate the layer.
And Put 'upStroke'layer on 'IMAGE layer', Z Clip front to 0, Z Clip back to 'distance - Camera to IMAGE layer'
And then, Put 'downStroke'layer down 'IMAGE layer', Z Clip front to 'distance - Camera to IMAGE layer', Z Clip back to just 30000...
If you want to animate your camera, the 'distance - Camera to IMAGE layer' can be expressed by Expression~.
length(thisComp.layer('IMAGE layer Name').transform.position, thisComp.layer('Camera 1').transform.position)