## Introduction: Laser-cut 64 Tetrahedron Made Out of Glass

From our previous projects, you might have noticed that we have a fascination for geometric shapes. One shape that had recently caught our eye was the 64 tetrahedron. As the name suggests, the shape is constructed using 64 individual tetrahedrons. A tetrahedron can be considered as a 3D triangle, it has four faces that are equilateral triangles of the same dimension.

The project was built using digitally fabricated parts with the help of a laser cutter and a 3D printer. If you like this project do support it by dropping a vote for it in the "Glass Challenge".

## Step 1: Overview of the Design

As the name suggests the 64 tetrahedron is built using 64 individual tetrahedrons. A tetrahedron is a 3D shape built using 4 equilateral triangles of the same dimensions. (Similar to a pyramid, but 3 sides instead of 4 and a triangular base instead of a square. The 64 tetrahedron can also be considered to be built using 8 larger opposing tetrahedrons that form a star shape and these larger star shapes are built using 8 tetrahedrons each.

We build a 3D model using Autodesk's Fusion 360 to get a better idea of the design. We then used the model to generate the files for laser cutting and 3D printing. The CAD files can be found attached below.

## Step 2: Materials Needed:

There are two approaches to build this project. You can either directly use a thin mirror, but very often for most people handling mirrors might be difficult and dangerous. Or you can use 2mm plexiglass along with a reflective film.

If you decide to use a mirror, you will need:

• A piece of 60x30cm mirror

If you decide to use plexiglass, you will need:

The tools required for this project are:

The total price of the project, excluding the tools is approximately 15\$ if you decide to use plexiglass.

## Step 3: Lasercutting the Pieces and 3D Printing the Guides

The panels that make up the tetrahedrons are laser cut. In total, 64 tetrahedrons are required, and each tetrahedron requires 4 equilateral triangles, which means that we will require 256 equilateral triangles. Depending on the size you want the final product to be you can determine the size of the individual triangles. In our case, we wanted the final product to be approximately 20-25 cms tall, which meant that we required triangles whose edges were 4cm in length.

The complete laser cutting designs can be found attached below.

To help with the assembling of the tetrahedron, we 3D printed a similar-sized tetrahedron to work as a jig. We also 3D printed a tool to help with the spacing while using tape to join the triangles to form the tetrahedrons.

The design of the spacing tool and jig can be found attached below.

## Step 4: Making the Tetrahedrons

Once all the pieces are laser cut, grab 4 of the triangles and use the spacing tool to create a gap between them. Next use clear tape to join the two pieces together. Repeat this process until you have joined all four. Use the 3D printed tetrahedron to form the tetrahedron. Once the shape is achieved, remove the jig and attach the base with some more clear tape. Make sure to align the edges well to get the best effect.

Repeat this process for the remaining 63 tetrahedrons. An extra pair of hands might come in handy for this step.

Refer to the images attached above for a better understanding of the process.

## Step 5: Silvering the Faces

Once all of the 64 tetrahedrons are made, you can begin to silver the faces. Cut the reflective film using an x-acto knife using one of the triangles as reference. Peel the protective covering of the film and align it with one of the faces of the tetrahedron. We recommend using a squeegee tool or an old business card to avoid air bubbles while applying the film. We covered three of the four faces of the tetrahedrons. Do this for all of them.

## Step 6: Building the Opposing Tetrahedrons

The 64 tetrahedron is built from 8 opposing tetrahedrons that form a star shape. These opposing tetrahedrons are built using two larger tetrahedrons that are built using 4 small tetrahedrons. The 8 tetrahedrons can be hot glued together to form the star shape.

You can refer to the animation attached above.

Begin by forming a large tetrahedron using 4 smaller tetrahedrons. Next, fill the "gaps" with four more tetrahedrons to form the star. Repeat this process 7 more times to build the 8 stars to complete the 64 tetrahedron.

## Step 7: Assembling the 64 Tetrahedron

Once he 8 stars are made using the tetrahedrons you can begin the assembly of the 64 tetrahedron. This process might be a little confusing at first but you will soon get the hang of it. Use hot-glue to stick two stars along the bottom left and bottom right of a third star. The joints from a "+" shape. Next, add a fourth star to the top of the central one. With the topmost star in place, you can add the back left and back right stars and finish the 64 tetrahedron with the last star that is attached at the back.

Refer to the animation and pictures attached above in case of doubts.

A nylon string can be attached to the tip of the 64 tetrahedron in case you plan to hang it. If you plan to place it on the table, we recommend that you build a simple stand for it.

## Step 8: Final Results

And that's it - the build is finished!

You can now hang it in a well-lit environment and be mesmerized by the stunning reflections and shadows that it creates against the walls. Apart from hanging it, you could simply place it at your desk or on a display shelf and it will definitely be a conversation starter.

If you enjoyed this Instructables and are inspired to try to make your own, do support us by voting for this project in the "Glass challenge". Feel free to leave any questions, comments, or suggestions about our build. Make sure to also share your own creations that are based on or inspired by ours, we would love to see them.

Thank you, for reading and till next time! :)

Participated in the
Glass Speed Challenge