Jack-o'-Lantern — Hollow Light Shell

Most printable jack-o'-lanterns are solid lumps with the face scratched into the surface. This one

is a shell: a 4.2 mm wall, an open underside, and eyes, nose and mouth cut all the way through into

the cavity. Put a light under it and the face glows. Leave it dark and it is still a pumpkin.

The photos are a real print of this file at 60 % scale — 59.6 × 60.0 × 48.7 mm, about 26 g of PLA.

What is measured, not guessed

- Wall 4.2 mm at the crown of the file, 2.5 mm at 60 %. That is three or four perimeters at a 0.4

nozzle — the shell prints as solid wall, no infill needed.

- The cavity is 208 cm³ in the file. The mesh volume is only 12 % of the bounding box; a solid

pumpkin of this shape would be five times heavier.

- Four openings, cut through — two eyes, nose, mouth. Confirmed on the geometry, not by eye: the

surface has genus 4, which is only possible if four holes pass through it.

- The underside is open. At plate level the clear opening takes a ⌀ 28 mm circle at 100 %, ⌀ 17 mm

at 60 %. Five millimetres up it is already 67 mm wide.

- Watertight — zero open edges, one connected solid, 199 992 triangles. Two non-manifold edges left

over from decimation; every slicer I know of merges them without a word.