$fn=64;

// --- Parametric Variables ---
disc_diameter = 100;     // Outer diameter of the insert disc
disc_thickness = 3;      // Thickness of the grid plate
grid_spacing = 8;        // Distance between grid lines (hole size)
grid_width = 2;          // Width of the grid lines
foot_height = 8;         // Height of the standoff feet for drainage
foot_diameter = 6;       // Diameter of the standoff feet

// --- Main Assembly ---
union() {
    // Outer support ring
    difference() {
        cylinder(h=disc_thickness, d=disc_diameter);
        translate([0, 0, -1])
            cylinder(h=disc_thickness + 2, d=disc_diameter - grid_width * 2);
    }

    // Perforated raised grid pattern
    intersection() {
        cylinder(h=disc_thickness, d=disc_diameter);
        
        // Generate intersecting grid lines
        num_lines = ceil(disc_diameter / grid_spacing) + 1;
        start_pos = -(num_lines * grid_spacing) / 2;
        
        union() {
            for (i = [0 : num_lines]) {
                // X-axis bars
                translate([0, start_pos + i * grid_spacing, disc_thickness / 2])
                    cube([disc_diameter + 10, grid_width, disc_thickness], center=true);
                // Y-axis bars
                translate([start_pos + i * grid_spacing, 0, disc_thickness / 2])
                    cube([grid_width, disc_diameter + 10, disc_thickness], center=true);
            }
        }
    }

    // Standoff feet to elevate the disc and improve aeration
    translate([0, 0, -foot_height]) {
        // Center foot
        cylinder(h=foot_height + 0.1, d=foot_diameter);
        
        // Perimeter feet
        num_feet = 8;
        radius = (disc_diameter / 2) - foot_diameter;
        for (i = [0 : num_feet - 1]) {
            angle = i * (360 / num_feet);
            translate([radius * cos(angle), radius * sin(angle), 0])
                cylinder(h=foot_height + 0.1, d=foot_diameter);
        }
    }
}