////////////////////////////////////////////////////////////////////////////////////////////// // Paraboloid module for OpenScad // // Copyright (C) 2013 Lochner, Juergen // http://www.thingiverse.com/Ablapo/designs // // This program is free software. It is // licensed under the Attribution - Creative Commons license. // http://creativecommons.org/licenses/by/3.0/ ////////////////////////////////////////////////////////////////////////////////////////////// module paraboloid (y=10, f=5, rfa=0, fc=1, detail=44, x, hi){ // y = height of paraboloid // f = focus distance // fc : 1 = center paraboloid in focus point(x=0, y=f); 0 = center paraboloid on top (x=0, y=0) // rfa = radius of the focus area : 0 = point focus // detail = \$fn of cone hi = (y+2*f)/sqrt(2); // height and radius of the cone -> alpha = 45° -> sin(45°)=1/sqrt(2) x =2*f*sqrt(y/f); // x = half size of parabola translate([0,0,-f*fc]) // center on focus rotate_extrude(convexity = 10,\$fn=detail ) // extrude paraboild translate([rfa,0,0]) // translate for fokus area difference(){ union(){ // adding square for focal area projection(cut = true) // reduce from 3D cone to 2D parabola translate([0,0,f*2]) rotate([45,0,0]) // rotate cone 45° and translate for cutting translate([0,0,-hi/2])cylinder(h= hi, r1=hi, r2=0, center=true, \$fn=detail); // center cone on tip translate([-(rfa+x ),0]) square ([rfa+x , y ]); // focal area square } translate([-(2*rfa+x ), -1/2]) square ([rfa+x ,y +1] ); // cut of half at rotation center } } //paraboloid (y=50,f=10,rfa= 0,fc=1,detail=120); paraboloid (y=50,f=10,rfa= 0,fc=1,detail=120);