hollow cylinder 3d model

outer_r = 200; // 20 cm inner_r = 174.6; // 17.46 cm height = 200; // 20 cm bottom = 8; // base thickness in mm difference() { // Outer cylinder (open top) cylinder(h=height, r=outer_r); // Inner hollow (open top, sealed bottom) translate([0,0,bottom]) cylinder(h=height-bottom, r=inner_r); }