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From computer's perspective, 3D stands for three dimensions, defined as images that having the perception of depth. Besides of x and y axis, 3D images will have depth which is the z axis. Emerged from 3D images, sets of 3D images that created to be interactive with users and provide the real-time experiences in some specify environments for users are called as virtual reality. 
In order to view and interact with the 3D images in our computers, we usually need to install a special plug-in or viewer in the Internet browser. Virtual reality will require additional equipment sometimes to provide better experiences for users. 
2.2 3D Images Creation
Creation of 3D images basically can be divided into three stages, which are tessellation, geometry and rendering. The creation of 3D images usually will consume some time to create in detail. 
Tessellation Stage 
Models of the individual objects will be created based on some linked points which are made into a number of tiles, which also called as polygons.
Geometry Stage 
The tiles or polygons will be transformed in various ways in this stage. Meanwhile, the lighting effects will be applied in this stage.
Rendering Stage 
In rendering stage, the image transformed in the last stage will be render into objects with a very fine detail.
3. Virtual Reality
3.1 What is Virtual Reality?
Virtual reality, is a technology that integrating computer hardware and software to make user to be fully immersed into a real-time 3D virtual environment that which is computer-generated. The participant will be able to see, listen, control, interact, speak and even smell if that is possible in the environment. A virtual reality may either a networked or stand-alone. 
According to whatis.com, virtual reality is an artificial environment that created with software, and presents to users in a way that user suspends belief and treats it as a real-time environment and scene. 
In a single computer, a virtual reality is basically experienced through sight and sound. At a personal computer, a simplest look of virtual reality is formed by 3D images that can be explored by users interactively. It can be controlled or manipulating in a simple way, which is by keys on keyboard, and also the mouse. The image will be moving in some designed view, scenes, direction and it may navigate to be zoomed in and out. 
Figure 1: A Virtual Reality View
Takes From http://youreyeonthefuture.files.wordpress.com
3.2 Different Types of Virtual Reality
There are different schemas that classify the various types of virtual realities. Between these schemas, there is: 
Jacobson (1993a) suggest four types of virtual reality 
Immersive virtual reality
Desktop virtual reality
Projection virtual reality
Simulation virtual reality
Thurman and Mattoon (1994) have presented a model to differentiate the types of virtual reality, it is based on how closely the virtual reality is corresponding to the real life 
Figure 2: Thurston and Mattoon's verity scale for virtual reality .
Brill (1993; 1994b) delineated another classification schema for virtual reality. 
Immersive First Person
Through the window
Cab simulator environment
The research later on will be focused on Brill's classification for types of virtual realities.
3.2.1 Immersive First Person
Immersive virtual reality is providing immediate, first person experience in certain environment to user. Usually there will be computer interface devices such as position tracking devices, head-mounted display (HMD), audio systems providing 3D (binaural) sound, and also fiber-optic wired gloves in an immersive virtual reality. 
Figure 3: Immersive first person virtual reality
takes from: http://www.streamhead.com
3.2.2 Augmented Reality
Augmented reality is a variation version of immersive virtual reality. In Augmented reality, there is a see-through later of computer graphics which superimposed over the reality in order to highlight certain features and hence enhance the understanding within the environment.
One of the augmented reality applications is aviation where some of the controls can be highlighted. Controls which needed to land the airplane are one of the examples. Besides of that, many medical applications are also one of the augmented realities. 
3.2.3 Mirror World
Mirror world is one of Projected Realities, which contrast with the types mentioned before this. It provides a second person experience while immersive providing first person. In mirror world, user stand outside of the imaginary world, but can communicates with the objects in the imaginary world. Differ from immersive virtual reality, mirror world system use video camera as its input device. 
In the mirror world system, users will see their own images superimposed on or merged together with a virtual world, which will presented on a large video monitor or maybe a video projected image. The computer will then processes user images and then capture their movements, positions, or even the number of fingers raise. 
Mirror world system normally will be cheaper than total immersion systems, and users are not encumbered by wired gloves, head gear, and other interfaces. Example of Mirror World virtual reality is Myron Krueger's 'artificial reality' system such as VIDEOPLACE. 
Figure 4: Mirror World Virtual Reality
3.2.4 Through the Window
This kind of virtual reality is also known as desktop virtual reality, which the users navigate and view the 3D environment through the computer screen and devices. This type of virtual reality provides a first person experience, which is a variation from immersive virtual reality. One example of this type of virtual reality is the 3D architectural design planning tool, Virtus Walkthrough. 
3.2.5 Waldo World
Waldo World is a type of virtual reality application that involving real time computer animation. It is a form of digital puppetry. "Waldo" name is drawn from a fiction story by Robert Heinlein (1965). In Waldo World system, users wear electronic mask or some body armor installed with sensors to perform motion detection which is a puppeteer controls. In real time, computer animation figure will be generated on the screen or the motion will be performed by robot. 
As an example of Waldo World system, the Virtual Actors TM which developed by SimGraphics Engineering (Tice & Jacobson, 1992) are animated characters that generated by computer. These characters are controlled by human actors in the real time. In Virtual Actor, an actor will wears a "Waldo" which will keep track of the actor's eye brows, head, cheek, lip, and chin movements, and so allowing them to control the computer generated character with their own movement. 
3.2.6 Chamber World
Chamber World virtual reality is a small virtual reality projection theater which controlled by several computers. It provide the sense of freer movement to user within a virtual world more than the immersive virtual reality system and thus user can gain a better feeling of greater immersion. 
In Chamber World system, images will be projected on all of the walls that can be viewed in 3D with a HMD and show a seamless virtual environment. The CAVE is the first of these systems, developed at Electronic Visualization Laboratory at the University of Illinois. 
Cyberspace is a global artificial reality which can be visited simultaneously by lots of people via networked computers. Cyberspace is where we hooked up to a computer network or an electronic database, or talking on the phone. 
3.2.8 Cab Simulator Environment
Cab Simulator Environment is another type of first person virtual reality technology. It is essentially extended from traditional simulator. Lots of cab simulators applications are focused in entertainment and training. As example, AGC Simulation Products had developed a training system for police offices to be practiced in the environment which driving under high speed and dangerous condition. 
Figure 5: Example of Cab Simulator Environment, a Flight Simulation System.
3.3 What Virtual Reality helps?
Virtual Reality is being used in many fields now. It included educational, training, business, entertainment and even gaming. From entertainment perspective, virtual realities are always treating as a better environment for gaming and entertainment. Virtual realities providing a real time 3D environment, which users will preferred for entertainment.
Meanwhile, in real life situation, virtual realities are often used for training and educational purpose. There are virtual realities which simulating some environment that carried high risks to those trainees whose under training. For example, astronauts and pilots are using virtual realities to simulate the actual environment for training purpose before they are going for the real-life environment.
3.4 Software to Create Virtual Reality Effect
In the market there are some popular products that enable us to create some virtual reality effects on our own computers. The following products are popular among the market:
Ray Dream Studio
3D Studio MAX
4. Web3D and VRML
4.1 What is Web3D?
Web3D is neither a format nor a standard, but it stands for a concept of interactive 3D content through the Internet or also called as World Wide Web, with the objective of increase user's experience on browsing through the web content. Web3D merge the intuitive human sense of space and time towards the interaction of user interface and also the programming language integration for the purpose to produce a fresh and challenging technology among the World Wide Web.
4.2 What is VRML?
VRML stands for Virtual Reality Markup Language, a type of file format which describing interactive 3D objects and virtual worlds. Basically, VRML is designed to be used on a local system, networked system or distributed system, such as Internet or Intranet. Intention of VRML is to be a global interchange format for intergraded 3D graphics and multimedia systems.
Besides that, VRML have been used as one common type in variety of application areas, for example educational, engineering and scientific visualization, multimedia presentation, gaming and entertainment, virtual worlds and also in web pages. VRML authoring tools that used to create VRML files are currently available for many different platforms. Besides of VRML, OpenGL and Inventor are some other format which also used for 3D file formats.
4.2.1 History of VRML
VRML 1.0 Specification 1995
VRML 97 / 2.0 Specification 1997
X3D (and Java3D) Specification (in development)
3DMLWÂ (3D Markup Language for Web)
4.2.2 VRML Design Goal
Typically, VRML is designed to meet the following requirement as its goal:
Capable of create, edit and maintain VRML files in development of computer programs.
It serves as a automatic translation programs for converting other 3D formats into VRML files.
This describes the ability of making use and merges the dynamic 3D objects within the VRML world.
The ability to import a new object or instance type which is not defined in the VRML explicitly.
Be capable of implementation
The capability of implementation the VRML on wide range of systems.
Performance emphasizes the scalability and interactive performance of VRML files on a wide variety of computing platform.
Arbitrarily of a large and dynamic 3D virtual world.