Our friend off another yacht was suffering with his prescription sunglasses, as the rubber pads that protected his nose from the metal frame of the bridge had perished and collapsed. I was able to identify the shape of the metal pads and designed a shape that I thought could be made on the printer with the soft flexible TPU filament. I wrote a module to make the shape of the metal pad, and then made the shape by (in the 3D CAD software) rubbing a sphere around the outside of the pad shape.

$fn=90;
module elipse() {
    scale([1.8,1,1]) cylinder(1.1,3.4,3.4);
}

difference() {
    minkowski() {
        elipse();
        sphere(1.2);
    }
    elipse();
    translate([0,-2,0]) cube([15,4,1.5]);
}