25 Halloween 3D prints you can design yourself (with the prompts)

Model sites are full of Halloween STLs: skulls, bats, ghosts, the same articulated dragon in fifty colours. They are great when any skull will do. They stop being great when the decoration has to fit something: your tea lights, your front door, your fence post, the name of your kid, the costume belt that is 38 mm wide. That is the part of Halloween you can design yourself, in minutes, on the phone you are reading this on.

Below are 25 ideas in six groups. Each one says the measurement that matters, and the ones marked by hand you can shape for free with the hand tools; the others are a sentence to the AI. Every prompt in this post opens in the editor already typed.

Light: lanterns and tea light covers

1. Jack-o'-lantern cover for an LED tea light. Measure the tea light (most are 36 to 38 mm across) and ask for a hollow pumpkin with triangle eyes and a toothy grin that drops over it. How to size it.
2. A square lantern, by hand. The open box shape with 1.6 mm walls, two triangle eyes and a mouth cut through one wall with Cut's polygon, a name in Text on another. Print it as it comes, turn it over the tea light. Free, download included.
3. A ghost luminary. A tall rounded ghost, 2 mm walls, open at the bottom, two oval eyes cut through: the LED glows through white PLA.
4. A row of bat cut-outs for a string of fairy lights, each with a 5 mm hole for one bulb.
5. A lithophane-style name plate in front of an LED: thin (0.8 mm) letters engraved into a 2 mm white plate glow brighter than the rest.

PLA softens around 60 °C. LED tea lights only, never a real candle, in any of these.

Doors, walls and the front yard

1. A "Trick or treat" sign, by hand. The plate shape, 160 x 60 x 4 mm, raised Text 10 mm high, two holes for a ribbon. Free.
2. An over-the-door hook sized to your door. Measure its thickness (interior doors are usually 35 mm, front doors 45 mm) and ask for a 2 mm strap that still lets it close. More on hooks and mounts.
3. Gutter or fascia clips for light strings, sized to the lip of your gutter.
4. A fence post bracket for a skeleton or a sign, built around the post's real width.
5. Replacement ground stakes for an inflatable whose plastic stakes snapped, in PETG.
6. A house number with a bat on it, raised digits on a plate with screw holes.

Kitchen and party table

1. A cookie cutter with your kid's name, or a bat, a ghost, a pumpkin. Cutting edge, height and food safety.
2. Pumpkin carving stencil holder: two pins and a frame that hold a paper template on a curved pumpkin.
3. Drink markers: clip-on rings for a 7 mm wine glass stem, each with an initial or a small shape.
4. Name place cards standing in a slot, one per guest, by hand with Text.
5. A candy bowl divider that fits the bowl you already own, measured across the rim.
6. A cupcake topper base with a 3 mm peg.

Costume and cosplay

1. A belt buckle for the width of the costume belt (25, 38 or 50 mm). Costume parts that fit.
2. A headband mount for horns or ears, clipped on a 10 to 20 mm band.
3. LED eye holders for a mask: two 5 mm sockets on a curved strip.
4. A name badge or a sheriff star, raised text, a slot for a safety pin.
5. A clip that holds a phone torch on a costume strap, for walking at night.

Fix and store

1. The battery cover your animatronic lost, copied from the one that is left on its twin, or from a photo next to a ruler.
2. Spools for light strings: a reel with a slot for the plug, so next October starts untangled.
3. A storage box for the small decorations, inside size to what goes in it.

Why design rather than download?

A downloaded decoration is a fixed size. Scaling it in the slicer scales the hole for the tea light, the slot for the ribbon and the wall thickness with it, so the part that "almost fits" never quite does. A part built from your numbers keeps the fit and only changes what you ask: wider, taller, another hole. That is the whole idea of SpeakCAD: the most intuitive CAD for 3D printing, for people who own a printer and need a part that fits something they have.

How long, how much

A lantern or a sign by hand takes five to ten minutes on a phone. With the AI, the first version usually renders in a few minutes and each change in one to three. Shaping a part by hand (a hole, a cut, an added shape, text, rounded corners, a shell, every size typed in millimetres) is free, and so is downloading what you shaped. With the AI, a new part or a design change spends 3 credits, a small change 2 credits and a quick edit (a changed size or number) 1 credit; downloads are included in every plan, 4 credits without one. A new free account also gets its first AI part free (not offered in every country): some accounts get the credits right away, others confirm with a card first (a free trial, nothing charged that day); downloading the part spends 4 credits without a plan, like any AI work (every plan includes downloads).

G-code comes sliced with the official OrcaSlicer profile of one of 380+ printers, or download the STL or 3MF for your own slicer. No printer? Get it printed and delivered: about 2 to 3 weeks, so order before the last week of October.

The Halloween code: SPOOKY40

40% off your first month of any plan with the code SPOOKY40, until 2 November (first subscription). It applies itself at checkout when you came through one of these Halloween pages, and you can type it on the payment page too. Start with Maker: 50 credits a month for $7.99, cancel anytime. The hand tools, and the download of what you shape with them, are free without it. Every Halloween part and its prompt on one page: Halloween 3D prints.