$fn = 64;

// --- PARAMETERS ---

// Flat-to-flat inner size of a single hex cell (mm)
cell_inner_size = 25; 

// Thickness of the divider walls (mm)
wall_thickness = 1.2; 

// Total height of the divider (mm)
height = 30; 

// Outer clearance to ensure it fits easily inside the bin (mm)
clearance = 0.5; 

// --- CALCULATIONS ---

// Distance between centers of adjacent cells
center_pitch = cell_inner_size + wall_thickness;

// Radius to the points of the theoretical hex grid
nominal_radius = center_pitch / sqrt(3);

// Radius of the inner cutouts
cell_radius = cell_inner_size / sqrt(3);

// Offset needed to achieve the correct outer wall thickness minus clearance
outer_offset = (wall_thickness / 2) - clearance;

// --- MODULES ---

// Generates the 19 hex center positions (1 center + 6 inner ring + 12 outer ring)
module hex_centers() {
    for (q = [-2 : 2]) {
        for (r = [-2 : 2]) {
            if (abs(q + r) <= 2) {
                // Pointy-topped hex grid math
                x = q * 1.5 * nominal_radius;
                y = (r + q/2) * sqrt(3) * nominal_radius;
                translate([x, y])
                    children();
            }
        }
    }
}

// --- MAIN MODEL ---

linear_extrude(height) {
    difference() {
        // Outer profile: perfectly merged 19-hex shape, offset for wall thickness and clearance
        offset(delta = outer_offset, join_type="miter") {
            hex_centers() {
                // Small overlap added to ensure a manifold 2D union
                circle(r = nominal_radius + 0.01, $fn = 6);
            }
        }
        
        // Inner cutouts: exactly sized for the 19 individual cells
        hex_centers() {
            circle(r = cell_radius, $fn = 6);
        }
    }
}