$fn=64;

// --- Parameters ---
num_brushes = 6;
hole_diameter = 12;      // Diameter of the holes for the brush handles
spacing = 20;            // Distance between brush centers
wall = 4;                // Thickness of the walls

// Overall dimensions
holder_width = (num_brushes * spacing) + spacing; 
holder_depth = 35;
holder_height = 80;

// Center line for the holes
hole_y = (holder_depth + wall) / 2;

module brush_holder() {
    difference() {
        // Main solid block
        cube([holder_width, holder_depth, holder_height]);

        // Hollow out the front to create the top/bottom shelves and back wall.
        // Split into two cutouts to leave a center support pillar for easier bridging.
        cutout_width = (holder_width - 3 * wall) / 2;
        
        // Left cutout
        translate([wall, wall, wall])
            cube([cutout_width, holder_depth + 1, holder_height - 2 * wall]);
            
        // Right cutout
        translate([holder_width / 2 + wall / 2, wall, wall])
            cube([cutout_width, holder_depth + 1, holder_height - 2 * wall]);

        // Create holes and indents for the brushes
        for (i = [1 : num_brushes]) {
            hole_x = i * spacing;

            // Top through-holes
            translate([hole_x, hole_y, holder_height - wall - 1])
                cylinder(h = wall + 2, d = hole_diameter);

            // Bottom indents to keep brushes from sliding out
            translate([hole_x, hole_y, wall - 2])
                cylinder(h = 3, d = hole_diameter - 2);
        }
    }
}

brush_holder();