56 lines
1.6 KiB
OpenSCAD
56 lines
1.6 KiB
OpenSCAD
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/*
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* =====================================
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* This is public Domain Code
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* Contributed by: Gael Lafond
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* 24 March 2017
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* =====================================
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*
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* This is my attempt at creating a predictable
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* helix that can be created from any polygon.
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*
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* It works in a very similar fashion to rotate_extrude,
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* with a height parameter.
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*
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* The height of the final object is equal to the
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* height parameter + the height of the provided polygon.
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*/
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module helix_extrude(angle=360, height=100) {
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precision = $fn ? $fn : 24;
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// Thickness of polygon used to create an helix segment
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epsilon = 0.001;
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// Number of segments to create.
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// I reversed ingenering rotate_extrude
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// to provide a very similar behaviour.
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nbSegments = floor(abs(angle * precision / 360));
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module helix_segment() {
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// The segment is "render" (cached) to save (a lot of) CPU cycles.
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render() {
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// NOTE: hull() doesn't work on 2D polygon in a 3D space.
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// The polygon needs to be extrude into a 3D shape
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// before performing the hull() operation.
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// To work around that problem, we create extremely
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// thin shape (using linear_extrude) which represent
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// our 2D polygon.
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hull() {
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rotate([90, 0, 0])
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linear_extrude(height=epsilon) children();
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translate([0, 0, height / nbSegments])
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rotate([90, 0, angle / nbSegments])
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linear_extrude(height=epsilon) children();
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}
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}
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}
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union() {
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for (a = [0:nbSegments-1])
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translate([0, 0, height / nbSegments * a])
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rotate([0, 0, angle / nbSegments * a])
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helix_segment() children();
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}
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}
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