$fn = 64;

// --- Parameters ---
outer_radius = 50;       // Radius from center to outer hexagon points (approx 100mm wide)
total_height = 5;        // Total height of the coaster
rim_thickness = 3;       // Thickness of the outer wall
base_thickness = 2;      // Thickness of the bottom surface

// Calculate inner radius to maintain uniform rim thickness on the flat sides
// The angle for a hexagon is 30 degrees from corner to flat center
inner_radius = outer_radius - (rim_thickness / cos(30));

// --- Model ---
difference() {
    // Main outer hexagon body
    cylinder(r=outer_radius, h=total_height, $fn=6);
    
    // Inner cutout for the beverage area
    // Shifted up by base_thickness, made taller to prevent Z-fighting
    translate([0, 0, base_thickness])
        cylinder(r=inner_radius, h=total_height, $fn=6);
}