$fn = 64;

// --- Parameters ---

// Inner diameter of the ring (sized for ~76mm / 3-inch nursery pots)
ring_inner_dia = 78; 
// Total height of the main ring body
ring_height = 30;
// Thickness of the outer wall (needs to be thick enough to house the stacking groove)
wall_thickness = 7;

// Width of the bottom inward flange that supports the pot
flange_width = 10;
// Thickness of the bottom support flange
flange_thickness = 2;

// Height of the interlocking V-ridge for stacking
stacking_ridge_height = 2.5;
// Width of the interlocking V-ridge
stacking_ridge_width = 3;
// Clearance for easy stacking
clearance = 0.4;

// Drainage hole parameters
drainage_hole_dia = 6;
drainage_hole_count = 8;

// Grip texture parameters
grip_ridge_dia = 2;
grip_ridge_count = 32;

// --- Calculated Variables ---
r_in = ring_inner_dia / 2;
r_out = r_in + wall_thickness;
h = ring_height;
fw = flange_width;
fh = flange_thickness;
rh = stacking_ridge_height;
rw = stacking_ridge_width;
c = clearance;

// The ridge is centered in the wall. rim_outer is the flat top area outside the ridge.
rim_outer = 2; 

// --- Main Geometry ---
module stackable_pot_ring() {
    // 2D Profile for the ring, revolved to create the perfectly manifold 3D shape
    profile_points = [
        [r_in - fw, 0],                                // 0: Bottom inner flange edge
        [r_in - fw, fh],                               // 1: Top inner flange edge
        [r_in, fh],                                    // 2: Inner wall base
        [r_in, h],                                     // 3: Inner wall top
        [r_out - rim_outer - rw, h],                   // 4: Male stacking ridge inner base
        [r_out - rim_outer - rw/2, h + rh],            // 5: Male stacking ridge peak
        [r_out - rim_outer, h],                        // 6: Male stacking ridge outer base
        [r_out, h],                                    // 7: Outer wall top
        [r_out, 0],                                    // 8: Outer wall bottom
        [r_out - rim_outer + c, 0],                    // 9: Female groove outer base (with clearance)
        [r_out - rim_outer - rw/2, rh + c],            // 10: Female groove peak (with clearance)
        [r_out - rim_outer - rw - c, 0]                // 11: Female groove inner base (with clearance)
    ];

    difference() {
        union() {
            // Main revolved body
            rotate_extrude() {
                polygon(profile_points);
            }

            // Outer grip ridges
            for(i = [0 : grip_ridge_count - 1]) {
                rotate([0, 0, i * 360 / grip_ridge_count])
                translate([r_out - grip_ridge_dia/3, 0, 1])
                cylinder(d=grip_ridge_dia, h=h-2, $fn=16);
            }
        }

        // Drainage holes in the support flange
        for(i = [0 : drainage_hole_count - 1]) {
            rotate([0, 0, i * 360 / drainage_hole_count])
            translate([r_in - fw/2, 0, -1])
            cylinder(d=drainage_hole_dia, h=fh + 2, $fn=32);
        }
    }
}

// Render the model
stackable_pot_ring();