/usr/share/openscad/libraries/MCAD/curves.scad is in openscad-mcad 2014.03-1.
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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 | // Parametric curves, to be used as paths
// Licensed under the MIT license.
// © 2010 by Elmo Mäntynen
use <math.scad>
include <constants.scad>
/* A circular helix of radius a and pitch 2πb is described by the following parametrisation:
x(t) = a*cos(t),
y(t) = a*sin(t),
z(t) = b*t
*/
function b(pitch) = pitch/(TAU);
function t(pitch, z) = z/b(pitch);
function helix_curve(pitch, radius, z) =
[radius*cos(deg(t(pitch, z))), radius*sin(deg(t(pitch, z))), z];
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