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Becoming a repository of "cut" operators in OpenSCAD -- if your print bed is not large enough
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examples Added a round-box example that uses LeftRight directly Apr 16, 2019 More copy editing Apr 14, 2019


The problem

You have a beautiful 3D part that you would like to print. It is too big for your printer. What now?

The solution

Cut the part into several pieces, and print them separately!

But how?

But even once you printed the pieces seperately, how do you put them back together into that beautiful part? How do you align the pieces properly? And wouldn't it be better if the pieces were holding together with more than just glue, too?

Let's cut in a more ragged line! A Zigzag line would be great for alignment. Or maybe a cut in the shape of puzzle pieces, so we might not need any glue at all!

Sounds complicated? It could be. But here is a bit of OpenSCAD code that makes it simple: This is what it does:


  • A collection of pre-defined OpenSCAD "modules" that can take any 3D part defined in (or imported into) OpenSCAD, and cut it into two parts that can be printed separately.
  • Different cuts are available:
    • The Comb cuts rectangular notches into one of the pieces, and extends matching rectangular fingers on the other.
    • The ZigZag makes a zig-zag line from isosceles triangles.
    • The Puzzle makes, you guessed it, the typical puzzle piece form where the two pieces can be snapped together.
  • All settings have defaults, and you can override them, to define things such as:
    • the size of the box, triangle etc elements (height, width, etc)
    • the number and location of them, so you can pick the best place for them given the particularities of your beautiful 3D part.
    • the fit is configurable as well, so the parts snap together well given the particularities of your printer and filament.
  • In the simplest case (if you use the defaults), you just need to add 3 lines of code to your model:
    • At the beginning of the file, add a use ... statement to import the module defining the code you want to use.
    • The declaration of the cut, in front of your model, such as: Comb() {
    • Then ending } right after. This turns your part into two, separated by some distance and with the cut you chose.

Here's the best part:

  • You can define and use your own shape of cut, and it's almost as simple. All you need to do is define the shape of cut as an OpenSCAD 2D shape, and pass it into a module called LeftRight. This is how all the cuts we have predefined work.
  • Don't like our puzzle shape? Want something goofier? Define it as a 2D shape, and pass it it. The library will do the cutting for you.

How to get started

  • Check out this git repo.
  • In OpenSCAD, open up file examples/box-example.scad. This cuts a simple box into two parts.
  • NOTE: The OpenSCAD "preview" may mess things up. You need to perform a full rendering.
  • Then, open the same file in a text editor. There is a bunch of commented-out code. Uncomment one at a time, to see different kinds of cuts.
  • File examples/surface-example.scad cuts a more complicated part whose surface is generated from a data file (that is generated with a piece of associated python code -- you can ignore that). The image above on this page shows this example.

How to define your own cut:

Just look into comb.scad for an example. All you need to do is to define your cut as a 2-D object (we will extrude it suitably for you) and pass it in with your part into the LeftRight module as the second part.


  • Thingiverse user Rich Olson created a PuzzleCut OpenSCAD library here on Thingiverse, which inspired how to do some of this more simply than I could think of myself.
  • OpenSCAD forum user Jordan Brown helped in the OpenSCAD forum getting around some non-obviousness in the way OpenSCAD children() does (or perhaps does not) work.
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