Virtual reality explain


What is virtual reality?
Virtual reality (VR) means experiencing things through our computers that don’t really exist. From that simple definition, the idea doesn’t sound especially new. When you look at an amazing Canaletto painting, for example, you’re experiencing the sites and sounds of Italy as it was about 250 years ago—so that’s a kind of virtual reality. In the same way, if you listen to ambient instrumental or classical music with your eyes closed, and start dreaming about things, isn’t that an example of virtual reality—an experience of a world that doesn’t really exist? What about losing yourself in a book or a movie? Surely that’s a kind of virtual reality?

If we’re going to understand why books, movies, paintings, and pieces of music aren’t the same thing as virtual reality, we need to define VR fairly clearly. For the purposes of this simple, introductory article, I’m going to define it as:


Putting it another way, virtual reality is essentially:


We can see from this why reading a book, looking at a painting, listening to a classical symphony, or watching a movie don’t qualify as virtual reality. All of them offer partial glimpses of another reality, but none are interactive, explorable, or fully believable. If you’re sitting in a movie theater looking at a giant picture of Mars on the screen, and you suddenly turn your head too far, you’ll see and remember that you’re actually on Earth and the illusion will disappear. If you see something interesting on the screen, you can’t reach out and touch it or walk towards it; again, the illusion will simply disappear. So these forms of entertainment are essentially passive: however plausible they might be, they don’t actively engage you in any way.


Types of virtual reality
“Virtual reality” has often been used as a marketing buzzword for compelling, interactive video games or even 3D movies and television programs, none of which really count as VR because they don’t immerse you either fully or partially in a virtual world. Search for “virtual reality” in your cellphone app store and you’ll find hundreds of hits, even though a tiny cellphone screen could never get anywhere near producing the convincing experience of VR. Nevertheless, things like interactive games and computer simulations would certainly meet parts of our definition up above, so there’s clearly more than one approach to building virtual worlds—and more than one flavor of virtual reality. Here are a few of the bigger variations:

Fully immersive
For the complete VR experience, we need three things. First, a plausible, and richly detailed virtual world to explore; a computer model or simulation, in other words. Second, a powerful computer that can detect what we’re going and adjust our experience accordingly, in real time (so what we see or hear changes as fast as we move—just like in real reality). Third, hardware linked to the computer that fully immerses us in the virtual world as we roam around. Usually, we’d need to put on what’s called a head-mounted display (HMD) with two screens and stereo sound, and wear one or more sensory gloves. Alternatively, we could move around inside a room, fitted out with surround-sound loudspeakers, onto which changing images are projected from outside. We’ll explore VR equipment in more detail in a moment.


What about “virtual world” games like Second Life and Minecraft? Do they count as virtual reality? Although they meet the first four of our criteria (believable, interactive, computer-created and explorable), they don’t really meet the fifth: they don’t fully immerse you. But one thing they do offer that cutting-edge VR typically doesn’t is collaboration: the idea of sharing an experience in a virtual world with other people, often in real time or something very close to it. Collaboration and sharing are likely to become increasingly important features of VR in future.
