Just have to do the trig right, and remember that rotate() does the
rotation around X, then Y, then Z.
First, here's a general rectangular-to-polar conversion function:
function topolar3(p) = [
norm(p),
atan2(p.y, p.x),
atan2(norm([p.x,p.y]), p.z)
];
and now we'll use that to get the angles in a form for rotation:
function getangles(p1, p2) =
let (polar = topolar3(p2-p1))
[
0,
polar[2],
polar[1]
];
and finally we'll demonstrate:
p1 = [5,8,2];
p2 = [-20,-10,-10];
translate(p1) sphere(d=2);
translate(p2) sphere(d=2);
translate(p1) rotate(getangles(p1, p2)) cylinder(h=100, d=1);
Note: This works if you have a symmetrical object like a cylinder. If
it's not symmetrical and so you care which way it's rotated along its
new axis, that'll take another rotate, applied inside the rotate shown.
(It can be combined into that rotation, but it hurts my head to figure
out the resulting 3D rotate when you want to rotate around Z first.)
Just have to do the trig right, and remember that rotate() does the
rotation around X, then Y, then Z.
First, here's a general rectangular-to-polar conversion function:
function topolar3(p) = [
norm(p),
atan2(p.y, p.x),
atan2(norm([p.x,p.y]), p.z)
];
and now we'll use that to get the angles in a form for rotation:
function getangles(p1, p2) =
let (polar = topolar3(p2-p1))
[
0,
polar[2],
polar[1]
];
and finally we'll demonstrate:
p1 = [5,8,2];
p2 = [-20,-10,-10];
translate(p1) sphere(d=2);
translate(p2) sphere(d=2);
translate(p1) rotate(getangles(p1, p2)) cylinder(h=100, d=1);
Note: This works if you have a symmetrical object like a cylinder. If
it's not symmetrical and so you care which way it's rotated along its
new axis, that'll take another rotate, applied inside the rotate shown.
(It can be combined into that rotation, but it hurts my head to figure
out the resulting 3D rotate when you want to rotate around Z first.)
