Half of a 120-cell

Model originally uploaded to Thingiverse at https://www.thingiverse.com/thing:1145123.

This model is featured in figure 3.22 of Visualizing Mathematics with 3D Printing.

This is joint work with Saul Schleimer.

The 120-cell is one of the six regular 4-dimensional polytopes. This is the result of taking the edges of the polytope, radially projecting them onto the unit 3-sphere in 4-dimensional space, then stereographically projecting the result into our 3-dimensional space. We remove the half of the design in the hemi-3-sphere nearest to the projection point, which makes printing the image in 3-dimensional space feasible.

Video: https://www.youtube.com/watch?v=MyUfAs30yZk Shapeways: http://shpws.me/DqGB