Pantheon Benchmark: Codex 5.5

// Pantheon, Rome - stylized architectural model from front and aerial references.
// Units are arbitrary and chosen for proportion rather than survey accuracy.

$fn = 96;

stone = [0.72, 0.66, 0.56];
warm_stone = [0.62, 0.51, 0.42];
aged_marble = [0.82, 0.80, 0.72];
shadow = [0.13, 0.12, 0.11];
roof_tile = [0.44, 0.32, 0.22];
dark_roof = [0.24, 0.22, 0.19];
plaza = [0.52, 0.50, 0.45];

rotunda_r = 43;
rotunda_wall_h = 30;
dome_h = 28;
portico_w = 67;
portico_d = 45;
front_y = -76;

module triangular_prism(width, depth, height) {
    polyhedron(
        points=[
            [-width/2, -depth/2, 0], [ width/2, -depth/2, 0], [0, -depth/2, height],
            [-width/2,  depth/2, 0], [ width/2,  depth/2, 0], [0,  depth/2, height]
        ],
        faces=[
            [0,1,2],
            [3,5,4],
            [0,3,4,1],
            [1,4,5,2],
            [2,5,3,0]
        ]
    );
}

module rounded_step(radius, height, z, start_angle=0, end_angle=360) {
    color(stone)
    translate([0, 0, z])
        cylinder(r=radius, h=height);
}

module annular_cylinder(outer_r, inner_r, h) {
    difference() {
        cylinder(r=outer_r, h=h);
        translate([0,0,-0.1]) cylinder(r=inner_r, h=h+0.2);
    }
}

module rotunda_wall() {
    color(warm_stone)
    difference() {
        cylinder(r=rotunda_r, h=rotunda_wall_h);
        translate([0,0,-0.2]) cylinder(r=rotunda_r-3.2, h=rotunda_wall_h+0.4);

        // Deep shadowed entrance where the portico attaches.
        translate([-24, -rotunda_r-1, 0])
            cube([48, 12, 25]);
    }

    // Horizontal brick and cornice bands visible around the drum.
    for (z=[4, 10, 16, 22, 28]) {
        color([0.50, 0.40, 0.32])
        translate([0,0,z])
            annular_cylinder(rotunda_r+0.45, rotunda_r-0.35, 0.65);
    }

    color(aged_marble)
    translate([0,0,rotunda_wall_h-1.2])
        annular_cylinder(rotunda_r+1.4, rotunda_r-3.8, 2.1);

    // Small square openings in the ancient brick drum.
    for (a=[18:18:342]) {
        if (a < 210 || a > 330) {
            rotate([0,0,a])
            translate([rotunda_r-0.7, -1.0, 14])
                color(shadow) cube([1.1, 2.0, 3.2], center=true);
        }
    }
}

function dome_z(r, R, H, z0) = z0 + H * sqrt(max(0, 1 - (r/R)*(r/R)));

module dome_shell(R=42, H=28, z0=30, oculus=7.5, shell=1.6, steps=36) {
    outer = [for (i=[0:steps])
        let (r = oculus + (R-oculus)*i/steps)
        [r, dome_z(r, R, H, z0)]
    ];
    inner = [for (i=[steps:-1:0])
        let (r = oculus + (R-shell-oculus)*i/steps)
        [r, dome_z(r+shell, R, H, z0) - shell]
    ];

    color([0.70, 0.67, 0.58])
    rotate_extrude(angle=360, convexity=8)
        polygon(points=concat(outer, inner));

    // Oculus rim.
    color(aged_marble)
    translate([0,0,dome_z(oculus, R, H, z0)-0.9])
        annular_cylinder(oculus+1.4, oculus-0.2, 1.2);

    // Stepped concentric rings on the dome, strongest in aerial view.
    for (r=[13, 18, 23, 28, 33, 38]) {
        color([0.77, 0.74, 0.65])
        translate([0,0,dome_z(r, R, H, z0)-0.35])
            annular_cylinder(r+0.55, r-0.55, 0.55);
    }

    // Radial ribs following the dome curvature, important in the aerial reference.
    for (a=[0:10:350]) {
        rotate([0,0,a])
            curved_rib(R, H, z0, oculus+1.2, R-2.2);
    }
}

module curved_rib(R, H, z0, r1, r2, segments=12) {
    color([0.79, 0.76, 0.67])
    for (i=[0:segments-1]) {
        ra = r1 + (r2-r1) * i / segments;
        rb = r1 + (r2-r1) * (i+1) / segments;
        hull() {
            translate([ra,0,dome_z(ra, R, H, z0)+0.08])
                scale([1.0,0.38,0.28]) sphere(r=0.62, $fn=16);
            translate([rb,0,dome_z(rb, R, H, z0)+0.08])
                scale([1.0,0.38,0.28]) sphere(r=0.62, $fn=16);
        }
    }
}

module column(x, y, h=25) {
    translate([x,y,0]) {
        color(aged_marble) cylinder(r=2.45, h=1.1);
        color(aged_marble) translate([0,0,1.0]) cylinder(r1=1.75, r2=1.55, h=h-2.0);
        color([0.68,0.64,0.57]) translate([0,0,h-1.2]) cylinder(r=2.0, h=0.8);
        color(aged_marble) translate([-2.3,-2.3,h-0.5]) cube([4.6,4.6,1.0]);

        // Dark flutes give the cylindrical columns definition in front renders.
        for (a=[0:30:330]) {
            rotate([0,0,a])
            color([0.38,0.36,0.33])
            translate([1.62,-0.05,3])
                cube([0.08,0.10,h-5]);
        }
    }
}

module portico() {
    // Stylobate and stair platform.
    for (i=[0:3]) {
        color([0.64,0.60,0.53])
        translate([-portico_w/2-i*2, front_y-i*4, -1.2-i*0.45])
            cube([portico_w+i*4, portico_d+i*6, 0.45]);
    }

    // Shadowed interior bay.
    color(shadow)
    translate([-27, front_y+10, 3])
        cube([54, 24, 21]);

    // Rear masonry transition into the rotunda.
    color(warm_stone)
    translate([-30, front_y+24, 0])
        cube([60, 22, 25]);

    // Double column row: eight in front, four inner columns for depth.
    xs = [for (i=[0:7]) -28 + i*8];
    for (x=xs) column(x, front_y+8, 25);
    for (x=[-20,-7,7,20]) column(x, front_y+27, 23.5);

    // Entablature with inscription band.
    color(aged_marble)
    translate([-portico_w/2, front_y+4, 25])
        cube([portico_w, 32, 4.2]);

    color([0.38,0.34,0.29])
    translate([-27.5, front_y+3.75, 27.2])
    rotate([90,0,0])
    linear_extrude(height=0.18)
        text("M AGRIPPA L F COS TERTIVM FECIT", size=2.35, halign="left", valign="center");

    // Triangular pediment and heavy cornice.
    color(aged_marble)
    translate([0, front_y+20, 29.2])
        triangular_prism(portico_w+4, 32, 12);

    color([0.58,0.54,0.48])
    translate([-portico_w/2-2.5, front_y+2, 28.7])
        cube([portico_w+5, 36, 1.1]);

    // Pitched roof running behind the pediment, visible from the aerial reference.
    color(roof_tile)
    translate([0, front_y+43, 29.3])
    rotate([0,0,0])
        triangular_prism(portico_w-4, 38, 9);

    // Low side walls of the portico block.
    color(warm_stone)
    translate([-portico_w/2, front_y+9, 0])
        cube([3, 38, 20]);
    color(warm_stone)
    translate([portico_w/2-3, front_y+9, 0])
        cube([3, 38, 20]);
}

module plaza_context() {
    color(plaza)
    translate([0,-18,-1.8])
        cube([130,135,0.35], center=true);

    // Curved foreground steps/fountain hinted in the front reference.
    color([0.66,0.63,0.56])
    translate([-56, -92, -1.1])
        cylinder(r=19, h=0.55);
    color([0.60,0.57,0.51])
    translate([-56, -92, -0.45])
        cylinder(r=14, h=0.45);
    color([0.28,0.34,0.35])
    translate([-56, -92, 0.05])
        annular_cylinder(10, 6.5, 0.55);

    // Piazza obelisk/fountain visible in the aerial reference.
    color([0.55,0.50,0.44])
    translate([55, -87, -0.3])
        cylinder(r=7.5, h=0.5);
    color([0.46,0.39,0.32])
    translate([55, -87, 0.2])
        cylinder(r=1.1, h=14);
    color([0.43,0.35,0.29])
    translate([55, -87, 14])
        cylinder(r1=1.2, r2=0.1, h=5);
}

module pantheon() {
    plaza_context();
    rotunda_wall();
    dome_shell(R=rotunda_r-1.2, H=dome_h, z0=rotunda_wall_h-0.2, oculus=7.2);
    portico();
}

pantheon();