5 Tetrahedrons and a Dodecahedron geometric model - straw construction

5 Tetrahedrons and a Dodecahedron Geometric Model. A straw craft project with 3D printed connectors.

Also known as Compound of Five Tetrahedrons is a very difficult model to assemble. A Dodecahedron is added and this makes the model so much easier to assemble. Have fun !

Files for Dodecahedron vertex –
D-1mm 1 x
20-D-1mm 20 x

Files for Tetrahedron vertex –
T-1mm 1 x
20-T-1mm 20 x

The diameters are 1mm and can be scale to any diameter. Eg – if a diameter of 4.8mm is required, just scale the part to 480%.

A Dodecahedron has 20 vertices and 30 edges. I use black color straws for this model and the internal diameter of the straw is 5.1mm. The length of the straw to make the edge is approximately 27mm. If the assembly with the Tetrahedron is too tight then increase the length or vice versa.

A Tetrahedron has 4 vertices and 6 edges. This model consists of 5 Tetrahedrons. A total of 20 vertices and 30 edges. I used colored straws for this model and the internal diameter of the straw is 5.6mm. The length of the straw to make the edge of the Tetrahedron is 82mm.

Straws come in many sizes and variations of the diameter. We will need some trial and error to get a good fit.

From the assembly it can be seen that every vertices of the Dodecahron and the Tetrahedrons are aligned. So the length of the straw that form the edge of the Tetrahedron is adjusted to maintain this alignment. Assemble the Dodecahedron first.

Link to 3D viewer for the complete assembly -
https://grabcad.com/library/5-tetrahedra-and-a-dodecahedron-geometric-model-1

This is printed in PLA with support. Scale accordingly and print one piece to test the fit.

Full disclosure: Straw connectors and geometric models are not my own original idea. The concept exists (or has existed) commercially, and there are many people tinkering with this on Thingiverse.