I presume the points of your polygon are represented by actual 3D Nulls ?
You’d want to create a comp-size solid, apply a ‘beam’-filter to it, and give it these settings: length 100%, adjust color, and width to taste.
the start and endpoints should both get this expression:
l=thisComp.layer(“1”);
l.toComp(l.anchorPoint)
(in my example the nulls ware simplu called “1” to “4”)
Now just change the name of the layer in the first line of the expression to draw a line from null 1 to null 2, change the expression of the endpoint to:
l=thisComp.layer(“2”);
l.toComp(l.anchorPoint)
Now add copies of the beam, make sure you enable “composite on original” in the beam effect (otherwise only the last beam gets rendered, and we want to see all of them), and change the expression to draw additional lines from 2 to 3, from 3 to 4, from 4 to 1, etc.