You open the door and step into an empty room. Within moments, you find yourself immersed in a far away world - in a jungle on the other side of the world, or on another planet. This Star Trek "holodeck" fantasy may sound far fetched, but it's getting much closer to reality than you may think.

With the booming popularity of the Oculus Rift, and virtual reality technology in general, it makes sense that the long-term vision of VR developers would be the sort of complete and total immersive environment made possible by the holodeck concept.

So what is the current state of technology when it comes to virtual reality rooms, and what breakthroughs and innovations are necessary to get us from here to a Star Trek world where you can slip away on an adventure, simply by walking through a doorway in your own house?

Whole-Room Projections

Is modern technology capable of producing a Star Trek holodeck experience? Sort of.

While it still isn't possible to materialize objects that you can touch and feel, right out of thin air, it is possible to trick your brain into thinking that you're having a truly immersive and semi-real experience, simply through projection.

One such project is the IllumiRoom idea under development by Microsoft for the past few years.

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This proof of concept system casts projections onto the walls near your TV screen in order to expand the experience of game-play outside the boundaries of the TV display itself.  On its project website, the team explains the concept as follows:

"IllumiRoom uses a Kinect for Windows camera and a projector to blur the lines between on-screen content and the environment we live in allowing us to combine our virtual and physical worlds. For example, our system can change the appearance of the room, induce apparent motion, extend the field of view, and enable entirely new game experiences."

The team was already able to produce effects like falling snow in a room that responds to the direction your vehicle is facing in a game, or a simulation called "Bounce", where researchers produced a "grenade" that rolled out of the TV set and bounced around the living room.

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The idea here is that a separate projection box would sit in the center of the room and project images onto and around the area where your TV is located. It isn't a very big stretch of the imagination to see how such a projection concept could be used on all four walls of a room.

However, even just the current IllumiRoom idea of the game images filling the entire peripheral view of your game experience is a pretty cool concept that will most likely make it to store shelves in the near future.

http://www.youtube.com/watch?v=re1EatGRV0w

This is all well and good, but it's all visual. A true holodeck would not only allow you to sit and play a game from the comfort of your couch, but it would also allow you to get up, walk around, and explore a virtual environment.

Walking Without Moving

In a room that's only 10 feet wide or 10 feet long, how are you supposed to explore a full virtual world without running into the walls?

Some of the more advanced research that took place within the past decade on this issue came from none other than the U.S. Army Research Lab.  More and more, military training involves the use of virtual reality systems, and part of the U.S. Army's development of those systems included the development of an omnidirectional treadmill.

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In 2011, researchers at the University of Louisiana who had worked with the Army on a "CAVE-like" virtual reality system, described the omnidirectional treadmill (ODT) in the following way:

"The ability of physically walking and running is accomplished through the incorporation of an omnidirectional treadmill (ODT) system as the floor of the CAVE. The ODT enables walking in all directions that is, users are able to walk in circles if they so desire to explore the virtual space."

A similar technology was produced by a combination of German, Italian and Swiss scientists who produced a giant omnidirectional treadmill system called CyberWalk.  The technology allows for 2D motion by combining an array of synchronous treadmill belts that can move in perpendicular directions. Diagonal motion combines the movement of the two belts at once.

http://www.youtube.com/watch?v=Af0Skxi4ftw

Watching the video is very impressive. The treadmill utilizes control algorithms that incorporate how the user changes speed and direction, modifying the motion of the treadmill to keep the user as close to the center of the platform as possible.

Yet another interesting solution is the technology developed by a company called Virtusphere.  The concept? Imagine a big bubble that you walk or run inside of, and it rolls around to accommodate your motion. I know, you're thinking it must be like one of those gerbil treadmills, right? You wouldn't be wrong.

http://www.youtube.com/watch?v=NmpOQZgHUMo

It's an idea that is really best suited for use in combination with Oculus Rift, but one could envision modifying the sphere concept with projections of the virtual world inside of it, without the use of a big, cumbersome headset.

One of the most recent VR motion systems is a product called Omni, by Virtuix.  It utilizes a technique that's a bit different than all of those discussed so far. The system isn't exactly a treadmill - it's a low-friction surface that works in combination with special shoes that have a sole configured to slide over the radial grooves in the curved floor of the device.

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It isn't quite the solution produced by omni-directional treadmill researchers up to this point, but the non-moving parts of Omni, combined with the smaller form-factor, make it a practical solution for the home. When placed in the context of a virtual reality "holodeck" room, it isn't clear whether a technology like Omni would be a solution, but it could be.

Interacting With a Virtual World

A true holodeck will need to be able to fool the human senses. So far we've discussed vision and motion, but what about touch? If you are exploring a virtual world, and you put your hand against a virtual tree, what kind of system would be able to make it feel like you're touching a real tree?

Some researchers are working with special electroactive polymers [Broken URL Removed] that can be used in gloves or fabrics to apply pressure on fingertips or other areas of the skin, simulating the feeling of touch. There is some promise there for entire outfits that may simulate touch over the entire body.

What about fabricating entire solid objects on-demand? Earlier this year, researchers at the University of Tokyo's Institute of Technology were able to use sound waves to suspend and manipulate small particles in mid-air.

http://www.youtube.com/watch?v=odJxJRAxdFU#t=20

Given, in this research the particles were extremely lightweight, but by creating what researchers called an "ultrasonic focal point", researchers were able to actually levitate and move objects in the air.

This is probably the earliest and most speculative technology that could influence technological innovations for a future holodeck experience. Still, it's not too difficult to imagine the type of experience that would come from the combination of real-time particle manipulation with a "touch" simulator bodysuit.

Using Holograms for a Holodeck

These are only the tip of the iceberg when you explore emergent technologies surrounding the development of the virtual reality experience.  In some cases, the technology isn't even emergent, it's simply available for anyone ready to integrate it into the development of a holodeck room. One example of this is the touchable hologram, developed by researchers at the University of Tokyo in 2009.

Developers of the projector called it an "Airborne Ultrasound Tactile Display", which combined the hologram light projector with acoustic pressure to give the user the sense that holographic raindrops were actually landing on the user's hands.

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If you think holograms have no place in a future holodeck, think again. In April, Apple announced that it had patented an "Interactive three-dimensional display system" that allows users to manipulate a hologram with touches and gestures.

All of these technologies collectively form the building blocks of what could become a Star Trek holodeck in every home. Will this ever become a reality, or will gamers and adventurers forever be regulated to experiencing virtual reality with a massive display strapped to their heads?

Share your own thoughts and ideas of what a future holodeck will look like!

Image Credits: Wyatt Wellman Via Flickr, U.S. Army Research Lab's ODT with CAVE Graphics from PD-USGOV, Omni VR Motion System via Virtuix