I'm trying to reproduce David's answer here, and make variations.
When I assign a material other than transparent to the Boolean Difference cutting Cube, as in the attached blend file, the cutting shape stops being invisible.
I would like to have a way to materialize the precise area which is being cut through and keep the Cube invisible: either by representing a "fill" material as in the previous question, or by making the inside edge of the Sphere a different material.
Desired result 1
Desired result 2
Can the "cut" area be materialized with a different material, either the "fill" of the shape receiving the cut or the line along which it is cut?