Making the Template for the 3D puzzle

This is a tutorial on how to make the puzzle in the picture above. You’ll be able to get the dimensions to generate the files for all parts of the puzzle at the end of this tutorial.

Part 1: Dimension Calculation

The most important measurement to keep in mind is the thickness of the material. My acrylic sheet was ½ inch thick, which dictated everything else about this project. Since your project will vary in thickness and spacing preference, sharing my .STL files wouldn’t do much for you.


(Also my puzzles didn’t fit at first, this systematic way to calculate is an afterthought to save you time. …ssshhh)


Consider the following picture, this puzzle consists of 3 pieces with slots cut out to fit the other pieces perpendicularly. I named the pieces based on the shape of the slots. Each square represents a building block of NxNxN.

Each square is N x N, where “N” is also the thickness of your material.

Each square has a margin/gap of “g” which represents the spacing you decide on.

All in all, you need 2 numbers, thickness of the material (“N”) and the amount of spacing between pieces (“g”). Now, figure out the remaining dimensions of your pieces based on the following reference diagram (click to enlarge):


Red shows what’s included

i.e. Max Width = 5 blocks inclusive or 5N + 4g
Min Slot width = 1 block with margins or N + 2g


Part 2: The Inner-Corner Issue

If you are making this project with a CNC laser cutter or a 3D printer, then you can skip this part. For the rest of us using a CNC mill, we know inner corners are limited by the flute diameter.

The following are ways to address that issue:

  • Sharpen the inner corners via post-processing
  • Incorporate air-pockets  in all inner corners
  • Rounding the outer corners, either add fillets in your design or via post-processing


Part 3: Solving the Puzzle

No help from me. Good luck with that! 😉


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