Pantheon Benchmark: Claude Code 2.1 / Opus 4.7

// Pantheon of Rome - OpenSCAD model
// Approximate proportions based on the real building (units ~ meters).
//
//   +Y  ........ back (apse end of rotunda)
//   -Y  ........ front (portico faces -Y)
//   +Z  ........ up

$fn = 96;

// ============================================================
// Master dimensions
// ============================================================
// Rotunda (drum)
rotunda_r       = 26;          // outer radius
rotunda_h       = 22;          // drum height

// Dome
dome_outer_r    = 26;
dome_inner_r    = 21.5;
oculus_r        = 4.2;
dome_step_count = 7;           // number of horizontal step rings on lower part

// Portico (in front of rotunda, on -Y side)
portico_w       = 34;          // width along X
portico_d       = 15.5;        // depth along Y
portico_floor_h = 1.7;
entab_h         = 3.2;         // entablature
pediment_h      = 6.2;
pediment_thk    = 2.4;         // pediment depth (Y)

// Connecting block ("intermediate block" cella front between portico and rotunda)
inter_w         = 26;
inter_d         = 6;
inter_h_extra   = 4;           // height above pediment apex base (down to drum top region)

// Columns
col_h           = 12.5;
col_r           = 0.9;
col_base_h      = 0.45;
col_cap_h       = 1.0;
n_front_cols    = 8;
front_col_xinset = 1.6;        // inset of outer columns from portico edge

// Front steps
step_count      = 3;
step_h          = 0.25;
step_run        = 0.7;

// Where does the front face of the rotunda sit?
rotunda_front_y = -rotunda_r;                       // = -26
portico_back_y  = rotunda_front_y + 0.6;            // overlap slightly into rotunda
portico_front_y = rotunda_front_y - portico_d;      // = -41.5

// ============================================================
// Modules
// ============================================================

// Corinthian-ish column: base + tapered shaft (entasis) + flared capital + abacus
module column(h = col_h, r = col_r) {
    // Plinth (square base)
    translate([-r * 1.5, -r * 1.5, 0])
        cube([r * 3, r * 3, col_base_h * 0.35]);
    // Torus-like base ring
    translate([0, 0, col_base_h * 0.35])
        cylinder(h = col_base_h * 0.65, r1 = r * 1.35, r2 = r * 1.10);
    // Shaft with slight entasis (slight taper)
    translate([0, 0, col_base_h])
        cylinder(h = h, r1 = r * 1.02, r2 = r * 0.88);
    // Capital - lower bell, upper flare, square abacus
    translate([0, 0, col_base_h + h]) {
        // bell (the acanthus area, approximated)
        cylinder(h = col_cap_h * 0.50, r1 = r * 0.88, r2 = r * 1.15);
        // upper flare
        translate([0, 0, col_cap_h * 0.50])
            cylinder(h = col_cap_h * 0.25, r1 = r * 1.15, r2 = r * 1.30);
        // abacus (square block on top)
        translate([-r * 1.40, -r * 1.40, col_cap_h * 0.75])
            cube([r * 2.80, r * 2.80, col_cap_h * 0.25]);
    }
}

// Front steps - climb up to the stylobate (portico floor)
module front_steps() {
    // Number of climbing steps & layout
    n = 5;
    riser = portico_floor_h / n;     // each step's height
    tread = 0.55;
    sw = portico_w + 5;
    // Bottom step is the widest and extends furthest out
    for (i = [0 : n - 1]) {
        depth = (n - i) * tread + 0.5;  // outermost is largest
        width = sw - i * 0.6;           // slight inset each step up
        translate([-width/2,
                   portico_front_y - depth,
                   i * riser])
            cube([width, depth, riser + 0.01]);
    }
}

// Cylindrical drum (rotunda body)
module rotunda_drum() {
    // Main drum
    cylinder(h = rotunda_h, r = rotunda_r);

    // Two horizontal cornice bands (the real Pantheon has two)
    band(rotunda_h * 0.45, 0.4, 0.18);
    band(rotunda_h - 0.5, 0.55, 0.25);
}
module band(z, h, overhang) {
    translate([0, 0, z])
        cylinder(h = h, r = rotunda_r + overhang);
}

// Stepped exterior dome with oculus
module dome() {
    translate([0, 0, rotunda_h]) {
        difference() {
            union() {
                // Lower stepped section (about 55% of dome height)
                stepped_h_frac = 0.55;
                stepped_top_z  = stepped_h_frac * dome_outer_r;
                for (i = [0 : dome_step_count - 1]) {
                    f0 = i / dome_step_count * stepped_h_frac;
                    f1 = (i + 1) / dome_step_count * stepped_h_frac;
                    r0 = sqrt(max(0, 1 - f0 * f0)) * dome_outer_r;
                    r1 = sqrt(max(0, 1 - f1 * f1)) * dome_outer_r;
                    z0 = f0 * dome_outer_r;
                    z1 = f1 * dome_outer_r;
                    // Flat lip (horizontal step) + sloped riser between rings
                    lip_h = (z1 - z0) * 0.55;
                    rise_h = (z1 - z0) * 0.45;
                    translate([0, 0, z0]) {
                        // Horizontal lip - flat cylinder at radius r0
                        cylinder(h = lip_h, r = r0);
                        // Sloped riser bringing it up to next ring's radius
                        translate([0, 0, lip_h])
                            cylinder(h = rise_h, r1 = r0, r2 = r1);
                    }
                }
                // Smooth upper cap above the stepped section
                intersection() {
                    sphere(r = dome_outer_r);
                    translate([0, 0, stepped_top_z])
                        cylinder(h = dome_outer_r, r = dome_outer_r);
                }
            }
            // Oculus
            translate([0, 0, dome_outer_r - 1.5])
                cylinder(h = 5, r = oculus_r);
            // Hollow the dome (interior sphere)
            sphere(r = dome_inner_r);
        }
    }
}

// Portico: floor (stylobate), columns, entablature, pediment, back cella wall
module portico() {
    floor_top_z = portico_floor_h;
    col_total_h = col_base_h + col_h + col_cap_h;
    col_top_z   = floor_top_z + col_total_h;

    // Stylobate (raised floor)
    translate([-portico_w/2, portico_front_y, 0])
        cube([portico_w, portico_d, portico_floor_h]);

    // Column X positions (8 across front)
    inset = front_col_xinset;
    x_step = (portico_w - 2 * inset) / (n_front_cols - 1);

    // Y positions for three rows of columns
    y_front = portico_front_y + 1.6;
    y_mid   = portico_front_y + 6.0;
    y_back  = portico_front_y + 10.5;

    // Front row: all 8 columns
    for (i = [0 : n_front_cols - 1]) {
        x = -portico_w/2 + inset + i * x_step;
        translate([x, y_front, floor_top_z]) column();
    }
    // Middle row: 4 columns at outer positions (creates 3 aisles)
    mid_idx = [0, 2, 5, 7];
    for (i = mid_idx) {
        x = -portico_w/2 + inset + i * x_step;
        translate([x, y_mid, floor_top_z]) column();
    }
    // Back row: same positions as middle row
    for (i = mid_idx) {
        x = -portico_w/2 + inset + i * x_step;
        translate([x, y_back, floor_top_z]) column();
    }

    // Entablature - three horizontal bands (architrave, frieze, cornice)
    ent_y0 = portico_front_y - 0.3;
    ent_y1 = y_back + 1.6;
    ew = portico_w + 0.8;
    ed = ent_y1 - ent_y0;
    // Architrave (bottom band)
    translate([-ew/2, ent_y0, col_top_z])
        cube([ew, ed, entab_h * 0.35]);
    // Frieze (middle, slightly recessed)
    translate([-ew/2 + 0.15, ent_y0 + 0.15, col_top_z + entab_h * 0.35])
        cube([ew - 0.3, ed - 0.3, entab_h * 0.35]);
    // Cornice (top, slightly overhanging)
    translate([-ew/2 - 0.3, ent_y0 - 0.3, col_top_z + entab_h * 0.7])
        cube([ew + 0.6, ed + 0.3, entab_h * 0.3]);

    // Triangular pediment - on the front face only
    pediment_z0 = col_top_z + entab_h;
    translate([0, ent_y0, pediment_z0])
        rotate([90, 0, 0])
            linear_extrude(height = pediment_thk)
                polygon(points = [
                    [-portico_w/2 - 0.6, 0],
                    [ portico_w/2 + 0.6, 0],
                    [ 0,                pediment_h]
                ]);

    // Cella wall (back of portico, against rotunda) with door opening
    cella_w = portico_w - 6;
    cella_h = col_total_h + entab_h - 0.4;
    cella_y = y_back + 1.2;
    cella_thk = 1.6;
    door_w = 4.0;
    door_h = 9.0;
    difference() {
        translate([-cella_w/2, cella_y, floor_top_z])
            cube([cella_w, cella_thk, cella_h]);
        // Door opening
        translate([-door_w/2, cella_y - 0.1, floor_top_z + 0.0])
            cube([door_w, cella_thk + 0.2, door_h]);
    }
    // Door lintel inset
    translate([-door_w/2 - 0.3, cella_y + 0.2, floor_top_z + door_h])
        cube([door_w + 0.6, cella_thk - 0.4, 0.4]);
}

// Intermediate block (taller cella section between pediment and rotunda)
module intermediate_block() {
    // Top of pediment apex z:
    apex_z = portico_floor_h + col_base_h + col_h + col_cap_h + entab_h + pediment_h;
    // The intermediate block should rise to about apex level, slightly behind pediment
    h = apex_z - 0.5;          // sits on ground
    translate([-inter_w/2,
               portico_back_y - inter_d * 0.4,
               0])
        cube([inter_w, inter_d, h]);
}

// ============================================================
// Assembly
// ============================================================
module pantheon() {
    union() {
        rotunda_drum();
        dome();
        intermediate_block();
        portico();
        front_steps();
    }
}

pantheon();