openscad/dotSCAD
1
0
Fork 0
mirror of https://github.com/JustinSDK/dotSCAD.git synced 2025-09-01 10:42:57 +02:00
Code Issues Releases Wiki Activity

add string_tetrahedron

Browse Source
This commit is contained in:
Justin Lin
2019-09-19 10:10:32 +08:00
parent 4914dda1ac
commit 4c7ef79c17
1 changed files with 94 additions and 0 deletions
Download Patch File Download Diff File Expand all files Collapse all files

94
examples/string_tetrahedron.scad Normal file
View File

@@ -0,0 +1,94 @@
include <hull_polyline3d.scad>;
leng = 50;
thickness = 5;
segs_per_side = 20;
line_fn = 5;
model = "Tetrahedron"; // [Tetrahedron, Base, Both]
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);
for(i = [0:len(pts1) - 1]) {
hull_polyline3d(points = [pts1[i], pts2[i]], thickness = thickness);
}
}
function height(leng) =
leng * sqrt(1 - 4 / 9 * pow(sin(60), 2));
function vts(leng) =
let(
half_leng = leng / 2,
vt1 = [half_leng, 0, 0],
vt2 = [0, leng * sin(60), 0],
vt3 = [-half_leng, 0, 0],
vt4 = [0, half_leng * tan(30), height(leng)]
) [vt1, vt2, vt3, vt4];
module string_tetrahedron(leng, thickness, segs_per_side, line_fn) {
$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 base(leng, thickness, line_fn) {
vts = vts(leng);
r = leng / 4;
half_th = thickness / 2;
difference() {
sphere(r, $fn = 48);
translate([0, 0, -r])
linear_extrude(r)
square(r * 2, center = true);
translate([0, 0, height(leng) + half_th])
rotate([0, 180, 0])
translate([0, -leng / 2 * tan(30), 0])
hull() {
translate(vts[0])
sphere(half_th, $fn = line_fn);
translate(vts[1])
sphere(half_th, $fn = line_fn);
translate(vts[2])
sphere(half_th, $fn = line_fn);
translate(vts[3])
sphere(half_th, $fn = line_fn);
}
}
}
if(model == "Tetrahedron") {
string_tetrahedron(leng, thickness, segs_per_side, line_fn);
} else if(model == "Base") {
base(leng, thickness, line_fn);
} else {
translate([0, 0, height(leng) + half_th])
rotate([0, 180, 0])
translate([0, -leng / 2 * tan(30), 0])
string_tetrahedron(leng, thickness, segs_per_side, line_fn);
base(leng, thickness, line_fn);
}