$fn = 64;

// --- Parameters ---
cup_height = 140;           // Tall enough to support long brushes
bottom_outer_dia = 85;      // Wide base to prevent tipping
top_outer_dia = 70;         // Slightly narrower top opening
wall_thickness = 3;         // Sturdy walls for 3D printing
base_thickness = 5;         // Thick bottom for added weight and stability

// --- Main Object ---
difference() {
    // Outer shell
    cylinder(
        h = cup_height, 
        d1 = bottom_outer_dia, 
        d2 = top_outer_dia
    );
    
    // Inner cavity cutout
    // Translated up by base_thickness, and extended slightly past the top for a clean manifold cut
    translate([0, 0, base_thickness])
        cylinder(
            h = cup_height - base_thickness + 1, 
            d1 = bottom_outer_dia - (wall_thickness * 2), 
            d2 = top_outer_dia - (wall_thickness * 2)
        );
}