The evolution of computer technology enables us to simulate almost every aspect of human life. From science to sports, from education to entertainment, computer has a major impact on human civilization. And computer graphics help us bring those computer generated stuffs closer to reality. The evolution of computer graphics starts with text based computer applications. Then there was Graphical User Interface and 2D graphics. With 2D computer graphics, people can make images or animations that resembles real world objects. 3D computer graphics add the depth aspect to make virtual objects looks more real. To make it even better, people created stereoscopic imaging that create illusion of depth by imitating human eye mechanism. By using two separate images, one for each eye, the image will appears like it pops out our computer screen.

To make something looks real, we must be able to interact with it. Because of that, computer input devices has also evolved to enable user to interact in many ways. Keyboard, mouse, joystick, touchscreen, and motion sensor are some examples of input devices. But most interaction we find in computer games are not real enough. We can kick a ball in a football game with a simple button press, or unleash a powerful Hadouken with a four-button combo. We can't do that in real life.

Virtual reality is a technology that enables user to interact with computer generated objects or environments in such way that it looks or feels real for the user. A formal definition of virtual reality is "A computer generated, interactive three dimensional environment in which a person is immersed". Three keyword for virtual reality is computer-generated, interactive, and immersive.

The most notable example of virtual reality is The Matrix movie. In the movie, human are trapped in a virtual reality by intelligent machines. The virtual reality, called The Matrix, is so real that human thinks it is the real world. In real life, virtual reality used in many applications, such as pilot or navy training, driving or medical simulation, or even in computer games.

Display and input system are the most important components of a virtual reality application. It is common to use Head Mount Display for virtual reality application since it creates better immersion than standard display such as computer screens or projectors. It is also common to use earphones or speakers to create a realistic 3D sound. For the input system, the user needs a more natural way to interact with virtual objects, so they use gloves to receive hand movements or gestures, or some device that imitate real world object such as steering wheel for driving simulations.

Even with the current technology, virtual reality still has weakness. Today's virtual reality applications can't give sufficient feedback to all the five senses of human that can imitate a real feedback of a real object.

Even if the sight sense and hearing sense can be deceived by high tech computer graphics and 3D sounds, the other three senses still cannot be deceived. For our feeling sense, some input device can generate forces, vibrations, or motions to make interactions with virtual object are more realistic, but it still cannot imitate a feel of a real object. Questions like "How can we imitate wet?" or "How can we imitate gravity?" are yet to be answered. Researchers are still trying to find a way to fabricate smell and taste. But until then, we must be satisfied by the virtuality of the virtual reality.