include ; difference() { translate([0, 0, bumper_height / 2]) minkowski() { radius = bumper_diameter / 2 - bumper_edge_radius; height = bumper_height - 2 * bumper_edge_radius; cylinder(r = radius, h = height, center = true); sphere(r = bumper_edge_radius, center = true); } translate([0, 0, lid_height / 2]) cylinder(r = tube_inner_diameter / 2, h = lid_height, center = true); translate([0, 0, bumper_tube_depth / 2]) cylinder(r = tube_outer_diameter / 2, h = bumper_tube_depth, center = true); }