A joint Fermilab/SLAC publication

Developers create virtual CERN


Neng Xu sits in the cafeteria, where he was inspired to create a virtual CERN. Photo credit: Amy Dusto

Neng Xu, a software engineer for the University of Wisconsin-Madison working on the ATLAS experiment, sat drinking coffee in a sunny corner of CERN’s cafeteria when he thought of a challenge. Could he create a virtual version of what he saw out the window: a lawn with cafe tables and a building across the street?

He could, he found, and more. With the help of a colleague, Xu is now growing his virtual CERN into an interactive app that will work across multiple platforms and is slated for a public beta version sometime this fall. Fans of digital art got a preview of the tool at this month's Ars Electronica festival.

For years Xu has been a video game enthusiast. He’d toyed with the idea of making his own but ultimately decided, “Whatever I do, I can’t make better games than game companies.” Then he realized he could use the same type of software to do something different.

Xu used a free online game development tool called Unity to begin construction of the virtual cafeteria lawn and the building across the street, where in reality many physicists working on the ATLAS and CMS detectors have offices. Completing the project took two months of after-hours work. He’d included so much detail that the final file was huge, about 200 megabytes, and took nearly an hour to open.

When he moved on to his next idea, making a virtual model of the ATLAS detector, Xu cut down on the amount of information he included. That project took only half of a month to complete. After finishing it, Xu planted the virtual detector on the virtual lawn in front of the cafeteria to give a sense of the experiment’s enormity.

The ATLAS detector, parked in an usual spot. Image courtesy of Neng Xu

The resources coordinator for ATLAS saw the model. He asked Xu to make something similar that people outside of CERN could access online. Xu agreed. Although he was still working on this project beyond his day job, ATLAS began to provide him with some support. Besides software supplies, perhaps the most valuable asset Xu received was his introduction to fellow modeling innovator Joao Pequenao.

For the last decade, Pequenao has been working on multimedia, images and simulations for the ATLAS outreach office. While an undergraduate physics student in Lisbon, Portugal, he passionately pursued a hobby in graphic design. As the autodidact said, “Some kids play soccer, some kids go home to study [graphics] tools.”

Over the years, Pequenao's work has gained worldwide attention. The logo for this year’s Ars Electronica festival was his 2006 visualization of a proton collision forming a microscopic black hole.

“There was a niche in the market,” he said. ”I’m at the intersection of physicist, computer scientist and designer.”

Xu and Pequenao realized they could help one another. Along with Pequanao's student, Henrique Carvalho, they teamed up to become the first ATLAS group working on interactive multimedia.

Their new project, the ATLAS Virtual Interactive Online Navigator, or AVION, is a Web-based application that will soon be accessible to anyone with a laptop, smartphone, game console or other device connected to the Internet. Still in the alpha phase, AVION allows explorers to take guided tours of the experiment that start in the parking lot and delve underground into the LHC where collisions are occurring, or to examine individual pieces of the detector. Keeping up with Hollywood, the whole thing takes on an extra dimension with a pair of 3D glasses.

AVION takes the tour of CERN underground. Image courtesy of Neng Xu

AVION is designed to operate in a Web browser from any part of the world. Xu and Pequenao have visions of interactive games in the future in which players can build ATLAS and do their own physics analysis. And since the Unity engine is free online, the source files will be available to anyone who wants to download them, allowing users to modify AVION and create their own virtual CERN world.

“Add dinosaurs if you want,” said Xu.

Both he and Pequenao see AVION as a potentially valuable education tool for students and the public. “If you really have to build ATLAS, you will learn a lot,” Xu said.

The team expects AVION will be revealed to the world in the coming months via the ATLAS website.

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