dotSCAD/docs/lib-rotate_p.md

rotate_p

Rotates a point a degrees around an arbitrary axis. The rotation is applied in the following order: x, y, z.

Parameters

• point : The point [x, y, z].
• a : An array [deg_x, deg_y, deg_z]. The same as the a parameter of the built-in rotate.

Examples

You can use the code below to create a line.

hull() {
    sphere(1);
    rotate([0, -45, 45]) 
        translate([20, 0, 0]) 
            sphere(1);   
}  

The following code has the same effect.

point = [20, 0, 0];
a = [0, -45, 45];

hull() {
    sphere(1);
    translate(rotate_p(point, a))    
       rotate(a)  
           sphere(1);   
}  

The rotate_p function is useful in some situations. For examples, you probably want to get all points on the path of a spiral around a sphere.

radius = 40;
step_angle = 10;
z_circles = 20;

points = [for(a = [0:step_angle:90 * z_circles]) 
    rotate_p(
        [radius, 0, 0], 
        [0, -90 + 2 * a / z_circles, a]
    )
];

// Once you get all points on the path, you can place anything at each point.
// I just place a sphere as a simple demonstration.
for(p = points) {
    translate(p) 
        sphere(1);
}

%sphere(radius);