Impossible Passthrough

A twisted bar that screws through a slot that looks too small

One solid body, no colors. Works with every slicer.

Presets
Shape
mm
°

More twist makes the trick harder to see. Shape size times twist can be at most 1145, or the twisted sides overhang too much.

mm
mm

Gap between bar and slot. Raise it if the bar sticks.

Assembled only changes the preview. Downloads always contain the print layout.

Plate
mm
Colors

Two example settings, each from two angles. These are 3D renders of the model this page generates, not photos of prints.

Impossible Passthrough, print layout (3D render)Impossible Passthrough, print layout, closer view from above (3D render)
Print layoutShape: Star · Plate: Keychain · Text on the plate: “TWIST IT”
Impossible Passthrough, heart block (3D render)Impossible Passthrough, heart block, closer view from above (3D render)
Heart blockText on the plate: “FOR YOU”

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About this generator

A fidget that makes people ask how it works: the bar is clearly bigger than the slot, until you twist it through.

How to use

  1. Pick a shape and how much it twists.
  2. Add a name or a word on the plate if you like.
  3. Print the plate flat and the bar standing up, as exported.
  4. Hold the plate, put the bar's end in the slot and turn it while you push.

Printing tips

  • Print the bar standing up: the twist then needs no supports.
  • 0.2 mm layers keep the twisted faces smooth, so the bar turns easily.
  • Use two colors that contrast: the trick shows better on video.

Helpful guides

Frequently asked questions

The bar doesn't go through.

Turn it in the direction the twist runs while you push gently. If it still sticks, raise Clearance by 0.1 mm and print again.

Why does the slot look smaller than the bar?

The slot is twisted through the plate at the same rate as the bar. From above you only see a part of it, so it looks too narrow.

Can I make my own shape?

Pick Letter and type any letter or digit. Holes inside letters such as O or R are filled, so the slot stays one piece.

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