$fn = 64;

/* [Display Settings] */
// Number of display rows
num_tiers = 4;
// Width of the slots (60mm fits vertical ID cards, 90mm fits horizontal)
tag_width = 60;
// Thickness of the slots (allow extra clearance for easy insertion)
tag_thickness = 2.5;
// How deep the tag sits in the slot
slot_depth = 12;
// Tilt angle of the tags (degrees leaning back)
slot_angle = 15;

/* [Base Dimensions] */
// Depth of each step
tier_depth = 25;
// Height difference between steps
tier_height = 20;
// Height of the lowest step
base_height = 20;
// Thickness of the side walls
wall_thickness = 5;

// Calculated overall dimensions
overall_width = tag_width + (wall_thickness * 2);
overall_depth = num_tiers * tier_depth;

module id_tag_display() {
    // Note: The model is left solid. For 3D printing, it is highly recommended 
    // to print with low infill (e.g., 10-15% gyroid) to save material while 
    // avoiding the need for internal bridging supports that a hollow shell would require.
    
    difference() {
        // Main Body (Stepped Stand)
        union() {
            for (i = [0 : num_tiers - 1]) {
                translate([0, i * tier_depth, 0])
                    cube([overall_width, tier_depth, base_height + (i * tier_height)]);
            }
        }

        // Subtracted Tag Slots
        for (i = [0 : num_tiers - 1]) {
            tier_z = base_height + (i * tier_height);
            
            // Center the slot on the tier's depth
            translate([wall_thickness, (i * tier_depth) + (tier_depth / 2), tier_z])
                rotate([-slot_angle, 0, 0])
                // Translate down into the body, and center the thickness
                translate([0, -tag_thickness / 2, -slot_depth])
                // Make the cutter extra tall to cleanly break the top surface
                cube([tag_width, tag_thickness, slot_depth * 3]);
        }
    }
}

// Render the model
id_tag_display();