The Technology Behind Athena, An Immersive VR Rifle Controller

Ilium VR
3 min readDec 19, 2016

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One of the most important parts of any VR experience is perfect tracking of the hardware. For Athena and any other gun controller this mostly affects aiming, which is by far the most critically important aspect.

In the 2 years that we have been developing controllers we’ve tried a bunch of solutions to solve the problem of positional tracking, some internally developed, and some off the shelf solutions. After the release of the Vive and adding Vive support to our Persuader Developer kit, we knew that the Lighthouse system is the best tracking tech available right now.

Lighthouse technology

As of now Athena is the one of the only 3rd party peripherals with Lighthouse technology built into the product. It allows us to have near-perfect tracking and software support for pretty much any game on the SteamVR platform.

The Lighthouse system was internally developed by a team at Valve led by Alan Yates. Once the technology was far enough along, it was licensed to HTC to develop the Vive headset and controllers. Now they have opened up the license to a bunch of other companies to develop 3rd party hardware, including Ilium VR.

How it works

In the Lighthouse system the 3 main components are the tracked object, the Base station, and the computer.

The tracked object is usually a Headset or controller. In this case it is Athena. Athena has a gyroscope and accelerometer, and a couple dozen infrared sensors placed all over it’s surface. These sensors detect infrared lasers emitted from the Base Stations.

The Base Stations are mounted on opposite sides of your play space and emit sweeping laser lines across the room. Athena records the specific time that each sensor detects those laser lines, and sends that data to your computer.

Along with the infrared sensor data, Athena sends the motion data from the gyroscope and accelerometer. Your computer and the SteamVR software take all of this data, put it through some complex calculus and trigonometry, and figure out the position of the controller. The sensors and lasers are calibrated so precisely that the position is accurate to under a millimeter.

That level of accuracy is incredibly important for all VR experiences, and especially peripherals like Athena.

SteamVR

SteamVR is the software platform that supports all of this. It serves as the glue between the physical devices and the games that use them. The device interface to SteamVR is pretty generic. It only needs to know how many sensors there are and where they are, as well as a 3D model to represent the controller in game.

Once all of that information is plugged in the SteamVR driver does all of the hard work of making Athena compatible with any SteamVR game out there. Athena provides all of the inputs that a regular Vive controller does, so at a basic level all of the same interactions will work.

With a small amount of software, which Ilium VR provides, Game studios can support all of the additional features that Athena’s hardware has built in.

You can find out more about Athena and our Indiegogo campaign to launch this controller here: https://www.indiegogo.com/projects/athena-by-ilium-vr#/

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Ilium VR

Ilium VR builds products to put the virtual world in your hands.