Sarah Tew

Virtual reality pioneer Oculus VR doesn't just want to get its products on your head, it wants them in your hands as well.

The headset maker has been quietly preparing motion controllers -- devices that let you drive the action and manipulate objects in games with hand and body movements -- to complement its forthcoming goggles, people familiar with the development process say. The result: a more immersive experience in video games and other simulations.

But it's the implications of this technology that may have broader impact in the real world. By marketing its own motion controllers, Oculus may upset developers on its platform.

More than a half-dozen companies are developing their own motion control devices to compliment Oculus's headset, called the "Rift." Investors, developers and early customers have already sunk millions of dollars into these technologies; meanwhile, the companies have formed partnerships with software makers to include specialized code to support their devices.

Industry insiders say it's natural for Oculus to begin work on motion controls, particularly because they've become popular among the many game developers. But by doing so, Oculus will also effectively compete against accessories makers who are among the most valuable and vocal champions of its products.

"Oculus's responsibility is to consumers at the end of the day," said Julian Volyn, co-founder of Trinity VR, a startup creating motion controllers. Like many other motion controllers being launched, Trinity is turning to users on the crowd-funding site Kickstarter to support its development.

It's unclear when Oculus will reveal its motion controllers to the public. The company has yet to announce a formal launch date for the "Rift" headset, though some industry watchers expect it to arrive next year. Following an agreement to be acquired by Facebook for $2 billion in March, Oculus has said it is creating new prototypes of its products with specialized parts to ensure higher quality.

Oculus isn't the first company to face the potential of creating a product that could hurt some developers on its platform. Apple was at times criticized for integrating popular functionality into its computer operating system that had been developed by outside software makers, effectively killing that third-party business. Microsoft has also been accused of such practices in the past; It recently raised the ire of some computer partners when it launched the Surface tablet, its first PC.

For Oculus, there is a lot of pressure to make the best possible product that attracts customers to its platform, Volyn added. "It makes sense for them to take matters into their own hands."

An Oculus spokesman declined to comment.

A new move

Nintendo popularized motion control technology when it became the primary way customers interacted with its Wii video game console, launched in 2006. In the box was a wand, often called a "Wiimote," and a sensor that was placed above or below a television, translating the remote's movements onto the screen.

Bobby Kotick, Activision Blizzard's chief executive, once recalled in an interview how impressed he was when Nintendo demonstrated a prototype of the Wii controller with a fishing game; players flicked the Wiimote to mimic the real-world movement of casting out a lure.

"The idea was expressed in three seconds with one gesture," he said. The controls and their corresponding games became a cultural phenomenon.

The way motion controls work is deceptively simple.

Developers combine specialized software and hardware to sense each move of a controller with painstaking detail, interpret its meaning, and then turn it into a command in the game. The controllers themselves usually have a compliment of sensors, such as a gyroscope that can understand its position and whether it's laying flat, standing upright or turning in a circle. Some emit light that is seen by a camera that analyzes the intensity, size and other details to determine how close or far a player is from the screen.

The result: Players can imitate motions like swinging a sword or pulling the string of a archer's bow in the real world, and see their movements displayed in the game.

"When you can see your hands in the VR world, and these hands correspond to what your actual hands are doing, it's a very powerful experience," said Jan Goetgeluk, head of Virtuix. The startup makes a platform called the "Omni," which can track players' movements as they walk.

One of the most vexing drawbacks of many motion controllers is their limited field of vision. Since the cameras and sensors often face toward players, the motion controller usually stops working if you turn away.

Oculus currently sells a headset to developers for $350 that includes such a camera. Players position themselves in front of it in order to detect movements such as if they lean in or tilt their body. At least one prototype Oculus has developed attaches a camera to the headset, allowing for greater range of motion, people familiar with the development efforts say.

The company has also researched using magnetic fields, infrared lights and various cameras, all to determine where a player is in a room, as well as where and how their hands are moving, these people add.

In one case, the company researched technology similar to what had been developed by game maker Valve. That company created virtual reality headsets using images placed strategically around a room. A camera and computer would use those images to determine a player's position.

Whatever form Oculus's motion technology ultimately arrives in, many game developers agree it will add an additional sense of immersion to VR-enhanced video games.

"Everyone knows that hand tracking is a component that needs to be there," said Denny Unger, president of CloudHead Games, a virtual reality game maker. "It just has to be there."

For motion control makers on Oculus's platform, there aren't many other options to work with high-end game makers. Sony plans to integrate its own motion controls into its competing virtual reality technology for its PlayStation 4 video game console.

But new opportunities are emerging in the form of mobile devices.

A growing list of hardware manufacturers ranging from smartphone titan Samsung to gaming devices maker Razer have begun research and development of alternative virtual reality headsets, people familiar with the matter say. Many smaller companies are developing headsets to support multiple devices, including Apple's iPhone, as well. And even Google has indicated interest, with the announcement of its Cardboard project.

Some motion control makers say they're already preparing. Virtuix will offer support for mobile devices through a bluetooth connection. And Sixense Entertainment, which makes tools for integrating motion controls into virtual reality, is building support for Apple's iOS and Google's Android software as well.

Mobile devices will be key to the broader success of virtual reality, said Sixense CEO Amir Rubin. Many consumer's first virtual reality experiences will likely happen with a phone inserted into a headset, he added, representing an important opportunity for accessories makers.

"The motion controller that will succeed on mobile will be the default," he said.

Shara Tibken contributed to this report.