While it’s a bit awkward (the “right” way to go about it would probably be something like using Box3.getSize and Box3.getCentre, then built your own geometry with them) - Box3Helper is still just a 3d object - and you can extract it’s geometry (helper.geometry).
After you pick up the geometry, your creativity is the limit - mix the vertices with fat lines (both normal and dashed), remap them to a spline, go full Borderlands on the geometry with some custom shader.