Pantheon Benchmark: Cursor 3.5 / Composer 2.5

// Pantheon (Rome) — exterior model from ref-front / ref-top images
// Scale: 1 unit ≈ 1 m

$fn = 64;

rotunda_r   = 21.5;
drum_h      = 21;
dome_r      = 21.5;

portico_w   = 15.5;
portico_d   = 7.5;
col_h       = 11.8;
col_r       = 0.75;
col_count   = 8;
col_rows    = 3;
col_spacing = portico_w / (col_count + 1);

block_w     = portico_w;
block_d     = 5.5;
block_h     = drum_h;

entablature_h = 2.2;
pediment_h    = 3.2;
step_h        = 0.35;
step_count    = 3;

c_stone = [0.82, 0.78, 0.70];
c_brick = [0.55, 0.32, 0.22];
c_dome  = [0.62, 0.64, 0.58];
c_roof  = [0.48, 0.30, 0.20];
c_dark  = [0.42, 0.38, 0.34];

module cornice_ring(od, id, h, z) {
    color(c_stone)
        translate([0, 0, z])
            difference() {
                cylinder(h = h, r = od);
                translate([0, 0, -0.05])
                    cylinder(h = h + 0.1, r = id);
            }
}

module rotunda_drum() {
    color(c_brick)
        cylinder(h = drum_h, r = rotunda_r);

    cornice_ring(rotunda_r + 0.35, rotunda_r - 0.25, 0.5,  drum_h * 0.38);
    cornice_ring(rotunda_r + 0.45, rotunda_r - 0.15, 0.65, drum_h * 0.68);
    cornice_ring(rotunda_r + 0.55, rotunda_r - 0.05, 0.8,  drum_h - 0.85);
}

module dome_assembly() {
    step_h_ring = 0.52;
    n_steps = 7;
    z_dome = drum_h;

    for (i = [0 : n_steps - 1]) {
        ri = dome_r + 0.15 - i * 0.92;
        color(c_dome * (1 - i * 0.02))
            translate([0, 0, z_dome + i * step_h_ring])
                cylinder(h = step_h_ring, r1 = ri, r2 = ri - 0.88);
    }

    z_hemi = z_dome + n_steps * step_h_ring;
    color(c_dome)
        translate([0, 0, z_hemi])
            difference() {
                intersection() {
                    sphere(r = dome_r);
                    // keep upper hemisphere only
                    translate([-dome_r * 1.3, -dome_r * 1.3, -0.02])
                        cube([dome_r * 2.6, dome_r * 2.6, dome_r + 0.02]);
                }
                translate([0, 0, dome_r - 2])
                    cylinder(h = 5, r = 4.3, $fn = 72);
            }
}

module rotunda() {
    rotunda_drum();
    dome_assembly();
}

module corinthian_cap() {
    color(c_stone)
        translate([0, 0, col_h])
            cylinder(h = 1.0, r1 = col_r * 1.12, r2 = col_r * 1.4);
}

module column() {
    color(c_stone)
        cylinder(h = col_h, r = col_r);
    corinthian_cap();
}

module portico_columns(y_row_front) {
    z0 = step_count * step_h;
    row_depth = portico_d / (col_rows + 0.3);
    for (row = [0 : col_rows - 1])
        for (i = [0 : col_count - 1]) {
            x = -portico_w / 2 + col_spacing * (i + 1);
            y = y_row_front - row * row_depth;
            translate([x, y, z0])
                column();
        }
}

module triangular_prism(w, h, d, y0, z0) {
    color(c_stone)
        translate([0, y0, z0])
            rotate([90, 0, 0])
                linear_extrude(height = d, center = true)
                    polygon(points = [[-w / 2, 0], [w / 2, 0], [0, h]]);
}

module portico(y_front_face) {
    y_back = y_front_face - portico_d;
    z_cap = step_count * step_h + col_h + 1.0;

    // stepped platform (wide stylobate)
    for (s = [0 : step_count - 1]) {
        shrink = s * 0.4;
        color(c_stone)
            translate([0, y_front_face + 1.0 - s * 0.3, s * step_h + step_h / 2])
                cube([portico_w + 3.0 - shrink, portico_d + 2.4 - shrink * 0.4, step_h], center = true);
    }

    portico_columns(y_front_face - 1.0);

    // entablature (architrave + frieze)
    color(c_stone)
        translate([0, (y_front_face + y_back) / 2, z_cap + entablature_h / 2])
            cube([portico_w + 1.2, portico_d + 0.8, entablature_h], center = true);
    color(c_dark)
        translate([0, y_front_face - 0.15, z_cap + entablature_h * 0.55])
            cube([portico_w + 0.6, 0.35, entablature_h * 0.35], center = true);

    z_roof = z_cap + entablature_h;
    triangular_prism(portico_w + 1.4, pediment_h, 1.4, y_front_face - 0.2, z_roof);

    // pitched porch roof behind pediment
    color(c_roof)
        translate([0, (y_front_face + y_back) / 2 - 0.3, z_roof])
            rotate([90, 0, 0])
                linear_extrude(height = portico_d - 0.4, center = true)
                    polygon(points = [
                        [-portico_w / 2 - 0.2, 0],
                        [ portico_w / 2 + 0.2, 0],
                        [0, 2.6]
                    ]);
}

module intermediate_block(y_on_rotunda) {
    // rectangular connector flush against rotunda (+Y side)
    yc = y_on_rotunda + block_d / 2;
    color(c_brick)
        translate([0, yc, block_h / 2])
            cube([block_w, block_d, block_h], center = true);

    // low secondary pediment on top (visible behind main pediment in ref)
    color(c_stone)
        translate([0, yc + block_d / 2 - 0.5, block_h])
            rotate([90, 0, 0])
                linear_extrude(0.9, center = true)
                    polygon(points = [
                        [-block_w / 2, 0],
                        [ block_w / 2, 0],
                        [0, 2.5]
                    ]);
}

module plinth() {
    color(c_stone)
        translate([0, 8, -0.25])
            cube([rotunda_r * 2.6, rotunda_r * 2.2, 0.5], center = true);
}

module pantheon() {
    plinth();
    rotunda();

    y_rotunda_face = rotunda_r;
    intermediate_block(y_rotunda_face);

    y_portico_front = y_rotunda_face + block_d + 0.15;
    portico(y_portico_front + portico_d);
}

pantheon();