###### December 10, 2013

# Using 3D Printing To Visualize Theoretical Physics

**John P. Millis, PhD for redOrbit.com - Your Universe Online**

In my 'Introduction to Astronomy' course, I am often faced with a challenge: Many of the theoretical models that we have created to explain the Universe around us are quite difficult to visualize. This is sometimes particularly difficult for those not studying in a scientific field, but I even find myself struggling under the weight of mathematical constructs where the connection to reality is opaque at best.

Humans, in general, are very visual creatures, and theoretical science can sometimes leave us unsatisfied or confused. While it is not always vital for us to have a visual picture, sometimes it can reveal certain nuances that we would have overlooked simply by studying the math.Now a group of researchers from Imperial College London have created a means by which certain theoretical models can be visualized using a 3D printer. Study co-author Tim Evans shares what sparked this discovery: "The object was a table inspired by the tree-like structures found in nature, which is an example of a branching process that is commonly encountered in complex systems in theoretical physics. This led me to think, what other processes familiar to physics could be turned into a 3D printed object?"

The idea is that each individual point has certain properties, and therefore interacts with the surrounding points as the system continues to build. "The basic idea is simple," continued Evans. "A 3D printer builds up its object in layers. So the height of the object can be thought of as time. Suppose you have a mathematical model [that] defines a flat, two-dimensional picture that evolves in time — typically this will be a grid with some squares full and some empty. The mathematical model will define at each point in time what the printer should print at one height. The next step in the model will then define what to print on top of the first layer, and so forth. The result is a 3D object which shows how the mathematical model has evolved over time."

The team tested their idea by sculpting an algorithm that explains how forest fires spread over time. A somewhat chaotic system, the spread pattern can appear random, governed by individual cell interactions at a purely statistical level. But as a result of the 3D printing, researchers can demonstrate the burn pattern over time.

Now, Evans hopes to extend this study to his own work. "In our own group at Imperial we are trying to explain heartbeat anomalies by looking at simple models for the behavior of individual cells in heart muscle — it's possible that this could be visualized using 3D printing. Most models that represent the spread of disease could also be visualized. There may be many other examples and we just hope our rather literal translation from theoretical model to 3D printer output stimulates others to get creative."