width = 140;
height = 85;

diameter = 120;
shape_length = 50;
vent_length = 18;

wall_thickness = 3;

$fn = 100;

module squareToCircle(width, height, length, diameter, ovalfactor) {
    ovalf_h = 1.15;
    ovalf_w = 0.70;
    hull(){
        rotate([90,0,0])
        linear_extrude(1)
        square(size=[width, height], center=true);

        translate([0, length])
        rotate([90,0,0])
        linear_extrude(1)
        scale([ovalf_h, ovalf_w, 1])
        circle(r=diameter/2);
    }
    translate([0, length+10, 0])
    rotate([90, 0, 0])
    linear_extrude(10)
    scale([ovalf_h, ovalf_w, 1])
    circle(r=diameter/2);
}

module hollowStoC(width, height, length, diameter, ovalfactor, wall_thickness){
    difference(){
        squareToCircle(width, height, length, diameter, ovalfactor);
        translate([0, -0.005, 0])
        squareToCircle(width-2*wall_thickness, height-2*wall_thickness, length+0.01, diameter-2*wall_thickness, ovalfactor);
    }
}

module squareHole(width, height, length, wall_thickness) {
    translate([0, -length/2-1, 0])
    rotate([90, 0, 0])
    difference(){
        cube(size=[width, height, length], center=true);
        cube(size=[width-2*wall_thickness, height-2*wall_thickness, length+0.01], center=true);
    }
}

module diagonalPlate(width, length, thickness){
    difference(){
        rotate([-45, 0, 0])
        cube(size=[width, length, thickness], center=true);
        translate([0, -length*cos(45), 0])
        cube(size=[width+3, length, 20], center=true);
    }
}

module vent(width, height, length, wall_thickness) {
    squareHole(width, height, length, wall_thickness);
    translate([0, -length+1.1, 30])
    diagonalPlate(width, 10, 2);
    translate([0, -length+1.1, 15])
    diagonalPlate(width, 10, 2);
    translate([0, -length+1.1, 0])
    diagonalPlate(width, 10, 2);
    translate([0, -length+1.1, -15])
    diagonalPlate(width, 10, 2);
    translate([0, -length+1.1, -30])
    diagonalPlate(width, 10, 2);

    translate([0, -length, 0])
    rotate([90,0,0])
    difference(){
        cube(size=[width+15, height+15, 2], center=true);
        cube(size=[width, height, 2.01], center=true);
    }
}

hollowStoC(width, height, shape_length, diameter, 1, wall_thickness);
vent(width, height, vent_length, wall_thickness);

// translate([-120,0,0])
// cube(size=[100, 250, 10], center=true);