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41 lines
1.0 KiB
OpenSCAD
41 lines
1.0 KiB
OpenSCAD
use <shape_circle.scad>;
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use <polyline_join.scad>;
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use <util/sum.scad>;
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beginning_radius = 10;
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line_width = 2;
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fn = 3;
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number_of_polygons = 10;
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height = 2;
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linear_extrude(height)
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spiral_polygons(beginning_radius, line_width, fn, number_of_polygons);
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module spiral_polygons(beginning_radius, line_width, fn, n) {
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theta = 180 / fn;
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y = beginning_radius - beginning_radius * cos(theta);
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dr = y / cos(theta);
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pw = pow((beginning_radius + dr) * sin(theta), 2);
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half_line_width = line_width / 2;
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function a(ri, ro, i) = acos((pow(ro, 2) + pow(ri, 2) - pw * pow(0.985, i)) / (2 * ro * ri));
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module drawPolygon(r) {
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pts = shape_circle(radius = r, $fn = fn);
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polyline_join([each pts, pts[0]])
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circle(half_line_width, $fn = 12);
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}
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rs = [for(i = [0: n - 1]) beginning_radius + i * dr];
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as = [for(i = [1: n - 1]) a(rs[i - 1], rs[i], i) / 2];
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rotate(-as[0])
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drawPolygon(beginning_radius);
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for(i = [1:n - 1]) {
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rotate(sum([for(j = [0:i - 1]) as[j]]))
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drawPolygon(rs[i]);
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}
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} |