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add string_tetrahedrons

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Justin Lin 2020-09-22 13:40:26 +08:00
parent 182c6369d5
commit cfe8b04f64
1 changed files with 108 additions and 0 deletions
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examples/string_tetrahedrons.scad Normal file
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use <hull_polyline3d.scad>;
level = 1;
leng = 50;
thickness = 5;
segs_per_side = 10;
center = false;
module string_tetrahedron(leng, thickness, segs_per_side, line_fn) {
module lines_between(side1, side2, thickness, segs) {
function pts(p1, p2, segs) =
let(
p = p2 - p1,
dx = p[0] / segs,
dy = p[1] / segs,
dz = p[2] / segs
) [for(i = [0:segs]) p1 + [dx, dy, dz] * i];
pts1 = pts(side1[0], side1[1], segs);
pts2 = pts(side2[0], side2[1], segs);
leng = len(pts1);
hull_polyline3d(points = [pts1[0], pts2[0]], thickness = thickness);
for(i = [1:leng - 2]) {
hull_polyline3d(points = [pts1[i], pts2[i]], thickness = thickness);
}
end = leng - 1;
hull_polyline3d(points = [pts1[end], pts2[end]], thickness = thickness);
}
function height(leng) =
leng * sqrt(1 - 4 / 9 * pow(sin(60), 2));
function vts(leng) =
let(
half_leng = leng / 2,
center_y = half_leng * tan(30),
vt1 = [half_leng, - center_y, 0],
vt2 = [0, leng * sin(60) - center_y, 0],
vt3 = [-half_leng, -center_y, 0],
vt4 = [0, 0, height(leng)]
) [vt1, vt2, vt3, vt4];
$fn = line_fn;
half_leng = leng / 2;
vts = vts(leng);
vt1 = vts[0];
vt2 = vts[1];
vt3 = vts[2];
vt4 = vts[3];
lines_between([vt1, vt2], [vt3, vt4], thickness, segs_per_side);
lines_between([vt2, vt3], [vt1, vt4], thickness, segs_per_side);
lines_between([vt3, vt1], [vt2, vt4], thickness, segs_per_side);
}
module string_tetrahedrons(level, leng, thickness, segs_per_side, center) {
function height(leng) =
leng * sqrt(1 - 4 / 9 * pow(sin(60), 2));
if(level == 0) {
string_tetrahedron(leng * 2, thickness, segs_per_side, 6);
}
else {
half_leng = leng / 2;
center_y = half_leng * tan(30);
translate([0, center_y * 2])
string_tetrahedrons(level - 1, half_leng, thickness, segs_per_side, center);
translate([half_leng, -center_y])
string_tetrahedrons(level - 1, half_leng, thickness, segs_per_side, center);
translate([-half_leng, -center_y])
string_tetrahedrons(level - 1, half_leng, thickness, segs_per_side, center);
translate([0, 0, height(leng)])
string_tetrahedrons(level - 1, half_leng, thickness, segs_per_side, center);
if(center) {
rotate(60)
string_tetrahedrons(level - 1, half_leng, thickness, segs_per_side, center);
a = atan(height(leng * 2) / (2 * center_y));
for(i = [0:120:240]) {
rotate(i)
translate([0, -center_y * 2])
rotate([a, 0, 0])
translate([0, center_y * 2])
rotate([180, 0, 0])
scale(0.9427)
string_tetrahedrons(level - 1, half_leng, thickness, segs_per_side, center);
}
}
}
}
string_tetrahedrons(level, leng, thickness, segs_per_side, center);