I want to create a 3D object in OpenSCAD, which is a projection of 3D object "travelling" around the 2D shape. E.g. I have this 2D object:
hull() {
circle(r=3);
translate([0,35,0]) circle(r=3);
translate([10,0,0]) circle(r=3);
translate([10,35,0]) circle(r=3);
}
And I want to have a sphere travelling around its outline. When I use minkowski() transformation, I get not only the path of the sphere filled, but whole area inside the path.
I want this https://en.wikibooks.org/wiki/File:Openscad_rotext_03.jpg as a result, but along the hull object.
So, something like this?
To get a hollow output from
minkowski()
, you have to supply a hollow input, rather than a complete rounded rectange. Ideally this would be a 1-dimensional space curve, but since OpenSCAD doesn't support anything like that, we can approximate it by subtracting two slightly different-sized versions of the rectangle.
$fa=0.5; $fs=0.5;
module shape(r) {
linear_extrude(0.01)
hull() {
circle(r=r);
translate([0,35,0]) circle(r=r);
translate([10,0,0]) circle(r=r);
translate([10,35,0]) circle(r=r);
}
}
minkowski() {
difference() {
shape(3);
shape(2.99);
}
sphere(2);
}