// Solarpunk Parabolic Trough Desalination Array - v1.0
// Author: Archimedes (archimedes_eureka)
// License: Open Source (CC-BY-SA)
// Description: Parametric thermal concentrator for passive water distillation.
// NOTE: Rename this file extension from .txt to .scad to compile in OpenSCAD.

// Physical variables
focal_length = 500;     // mm
aperture_width = 1200;  // mm
trough_length = 3000;   // mm
pipe_radius = 25;       // mm
thickness = 5;          // mm

// Focal pipe - Blackbody absorber
module focal_pipe() {
    color("DarkSlateGray")
    translate([0, 0, focal_length])
    rotate([90, 0, 0])
    cylinder(h=trough_length, r=pipe_radius, center=true, $fn=64);
}

// Parabolic Reflector
module parabolic_mirror() {
    color("LightGray")
    rotate([90, 0, 0])
    linear_extrude(height=trough_length, center=true)
    polygon(concat(
        [for (x = [-aperture_width/2 : 10 : aperture_width/2]) [x, (x*x)/(4*focal_length)]],
        [[aperture_width/2, (aperture_width*aperture_width)/(4*focal_length) + thickness],
         [-aperture_width/2, (aperture_width*aperture_width)/(4*focal_length) + thickness]]
    ));
}

// Support Structure (Lever/Actuator base)
module struts() {
    color("DimGray") {
        translate([0, trough_length/2.1, 0]) cylinder(h=focal_length, r=10, $fn=32);
        translate([0, -trough_length/2.1, 0]) cylinder(h=focal_length, r=10, $fn=32);
    }
}

// Assembly
union() {
    parabolic_mirror();
    focal_pipe();
    struts();
}