3D Printed Models of Crystal Structures

For my spring 2016 course "Rapid Prototyping Technologies", I needed to design a final project using either laser cutting or 3D printing. As a materials science major, we learned a lot about crystal structures (i.e. how atoms are arranged in metals, minerals, etc.), and teachers loved to demonstrate them using molecular model kits. Theoretically, these kits allowed infinite possibilities, but some of the more complex structures, with varying bond lengths and intricate geometries, would be quite hard to build manually, so I came up with this idea of 3D printing crystal structures. This was hardly a novel idea, but the challenge lay in generating an STL file for every imaginable crystal structure, and I was obviously not going to CAD every single one of them in SOLIDWORKS.

Fortunately, crystal structure data are available in the form of CIF (Crystallographic Information File) files, which store the atomic types and positions of a particular crystal structure. My task then became writing a script that takes a CIF file as input and translating that into an STL file. The result looks something like this:

A rendering of CaF2 in Meshlab.

A 3D printed model of CaF2, which is not a diamond.

(Picture from my project page in the course gallery: https://www.cs.cmu.edu/afs/cs/academic/class/15294u-s16/gallery8/rundongj/)