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add spiral_plate

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Justin Lin
2021-03-24 10:51:42 +08:00
parent b7a2d4a3e7
commit 98bbc03988
1 changed files with 49 additions and 0 deletions
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examples/spiral_polygons/spiral_plate.scad Normal file
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use <ellipse_extrude.scad>;
use <util/sum.scad>;
beginning_radius = 15;
fn = 5;
number_of_polygons = 10;
layer_height = 1.5;
spiral_plate(beginning_radius, fn, number_of_polygons, layer_height);
module spiral_plate(beginning_radius, fn, n, layer_height) {
theta = 180 / fn;
y = beginning_radius - beginning_radius * cos(theta);
dr = y / cos(theta);
pw = pow((beginning_radius + dr) * sin(theta), 2);
function a(ri, ro, i) = acos((pow(ro, 2) + pow(ri, 2) - pw * pow(0.985, i)) / (2 * ro * ri));
module drawPolygon(r) {
circle(r, $fn = fn);
}
rs = [for(i = [0: n - 1]) beginning_radius + i * dr];
as = [for(i = [1: n - 1]) a(rs[i - 1], rs[i], i) / 2];
difference() {
h = layer_height * (n + 1);
translate([0, 0, h])
rotate(sum([for(j = [0:n - 2]) as[j]]))
mirror([0, 0, 1])
ellipse_extrude(layer_height * (n + 5), h)
drawPolygon(rs[n - 1] + y);
translate([0, 0, layer_height * 1.01]) {
rotate(-as[0])
linear_extrude(layer_height)
drawPolygon(beginning_radius);
for(i = [1:n - 1]) {
translate([0, 0, layer_height * i])
rotate(sum([for(j = [0:i - 1]) as[j]]))
linear_extrude(layer_height)
drawPolygon(rs[i]);
}
}
}
}