$fn=64;

// --- Parameters ---
tray_length = 180;        // Overall length of the tray
tray_width = 140;         // Overall width of the tray
tray_height = 35;         // Overall height of the walls to contain dice
wall_thickness = 4;       // Thickness of the outer walls
base_thickness = 3;       // Thickness of the bottom base (flat for felt application)
corner_radius = 20;       // Radius of the tray corners

// --- Modules ---
module rounded_box(length, width, height, radius) {
    hull() {
        translate([-length/2 + radius, -width/2 + radius, 0])
            cylinder(r=radius, h=height);
        translate([length/2 - radius, -width/2 + radius, 0])
            cylinder(r=radius, h=height);
        translate([-length/2 + radius, width/2 - radius, 0])
            cylinder(r=radius, h=height);
        translate([length/2 - radius, width/2 - radius, 0])
            cylinder(r=radius, h=height);
    }
}

// --- Main Geometry ---
difference() {
    // Outer body
    rounded_box(tray_length, tray_width, tray_height, corner_radius);

    // Inner hollowed area for rolling
    // Z is translated up by base_thickness to create the flat floor
    // Height is extended slightly to ensure a clean cutout at the top
    translate([0, 0, base_thickness])
        rounded_box(
            tray_length - (wall_thickness * 2),
            tray_width - (wall_thickness * 2),
            tray_height, // Extends past the top
            max(1, corner_radius - wall_thickness) // Maintain uniform wall thickness
        );
}