$fn=64;

// --- Parameters ---
columns = 3;
rows = 2;
total_width = 150;      // mm
total_depth = 100;      // mm
height = 40;            // mm
wall_thickness = 2;     // mm
bottom_thickness = 2;   // mm
corner_radius = 4;      // mm

// Calculated dimensions
comp_width = (total_width - (wall_thickness * (columns + 1))) / columns;
comp_depth = (total_depth - (wall_thickness * (rows + 1))) / rows;
inner_radius = max(1, corner_radius - wall_thickness);

// --- Modules ---
module rounded_box(w, d, h, r) {
    hull() {
        translate([r, r, 0]) cylinder(r=r, h=h);
        translate([w-r, r, 0]) cylinder(r=r, h=h);
        translate([r, d-r, 0]) cylinder(r=r, h=h);
        translate([w-r, d-r, 0]) cylinder(r=r, h=h);
    }
}

// --- Main Geometry ---
difference() {
    // Outer Shell
    rounded_box(total_width, total_depth, height, corner_radius);
    
    // Inner Compartments
    for (c = [0 : columns - 1]) {
        for (r = [0 : rows - 1]) {
            x_pos = wall_thickness + c * (comp_width + wall_thickness);
            y_pos = wall_thickness + r * (comp_depth + wall_thickness);
            z_pos = bottom_thickness;
            
            // Subtraction with +1 height to prevent Z-fighting at the top
            translate([x_pos, y_pos, z_pos])
                rounded_box(comp_width, comp_depth, height + 1, inner_radius);
        }
    }
}