53 lines
1.6 KiB
OpenSCAD
53 lines
1.6 KiB
OpenSCAD
D=300; // start diameter
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N=1; // number of spirals
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FN=100;
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$fn=FN;
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include <../libraries/path_extrude.scad>;
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/**
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* This approach is the fastest by far (!!!). Unlike spiral_4, this does not adjust
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* the $fn value as the spiral grows in diameter, but simply uses it as a constant
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* for all spirals. This means that the innermost spiral will have n=$fn facets and
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* the outermost facets will have the same number. Need to find a hybrid between
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* this and #4.
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**/
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module spiral (count = 40, start_d = 48, spacing = 2.075) {
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//$fn = 80;
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bottom = 1.2;
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top = .3;
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top_offset = (bottom - top);
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h = 2.2;
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angle_i = 360 / $fn;
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increment = spacing / $fn;
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facetProfile = [[0, 0], [top_offset, -h], [bottom, -h], [bottom, 0]];
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/**
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* Verbose
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spiralPath = [
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//for facet number times "count" or number of rotations
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//create an array containing [ x, y, z] values for path extrude
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for(t = [0 : $fn * count]) {
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[
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//starting radius + (iterator * increment size) * (cosine || sine) of (iterator * fractional angle
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((start_d / 2) + (t * increment)) * cos(t * angle_i), //x value
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((start_d / 2) + (t * increment)) * sin(t * angle_i), //y value
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0 //z value
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]
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}
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];
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**/
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spiralPath = [ for(t = [0 : $fn * count])
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[((start_d / 2) + (t * increment)) * cos(t * angle_i), ((start_d / 2) + (t * increment)) * sin(t * angle_i), 0] ];
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path_extrude(exShape=facetProfile, exPath=spiralPath);
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}
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spiral(N, D); |