Mix.install([{:smith, "~> 0.2.0"}, {:kino, "~> 0.19.0"}])Before you start
After the plate, compare three ways to make solids: push a ring-shaped sketch into depth, rotate a wall section into a sleeve, and connect two outlines with a loft.
Run cells in order. Lengths are millimeters and modeling angles are degrees. Each 3D preview supports orbit, zoom, and fullscreen.
Draw a ring
Sketches describe one connected planar region, optionally with holes. They can be previewed as faces before extrusion.
alias Smith.{Plane, Sketch}
outline = Sketch.circle(25) |> Sketch.cut(Sketch.circle(15))
Smith.Kino.render(outline, label: "1 · Ring sketch")Extrude along the normal
The normal is perpendicular to the sketch. On the default XY plane, positive extrusion goes along +Z. The flat ring becomes a 4 mm thick washer.
ring = outline |> Smith.extrude(4)
Smith.Kino.render(ring, label: "2 · Extruded ring")Revolve a cross-section
The XZ plane's local Y points along world Z. Keep the section to one side of the rotation axis to produce a hollow sleeve.
sleeve =
Sketch.rectangle(4, 20, align: {:min, :min}, at: {12, 0}, on: Plane.xz())
|> Smith.revolve({0, 0, 1})
Smith.Kino.render(sleeve, label: "Revolved sleeve")Connect sections with a ruled loft
A ruled loft joins each pair of outlines directly. Here two rectangles at different heights make a tapered transition. A smooth multi-section version appears in paths and shells.
transition = Smith.loft([
Sketch.rectangle(30, 20),
Sketch.rectangle(20, 10, on: Plane.xy(z: 30))
])
Smith.Kino.render(transition, label: "Ruled transition")Export the ring
{:ok, result} = Smith.evaluate(ring)
{:ok, volume} = OCEx.volume(result.shape)
true = abs(volume - :math.pi() * (25 * 25 - 15 * 15) * 4) < 1.0e-6
{:ok, files} = Smith.export(result, "output/livebook", name: "ring", on_bed: true)
files