Knowledge about virtual reality

Category: Computer/Network gt; gt; Computer knowledge

Problem description:

I hope it can provide some knowledge about virtual reality, preferably VRML Regarding that, thank you!

Analysis:

vrml virtual reality technology 1

Virtual reality is a more ideal form of human-computer interface between the computer and the user. Usually the user wears a helmet (a head-mounted display used to display stereoscopic images) and holds a sensor glove. As if in an illusionary world, the user roams in the virtual environment and is allowed to operate "objects" in it. Compared with traditional computers, virtual reality systems have three important characteristics: immersiveness, interactivity, and imagination. Virtual reality technology has a wide range of potential applications, such as national defense, architectural design, industrial design, training, and medicine. For example, architectural designers can use virtual reality technology to provide three-dimensional virtual models to customers, while surgeons can also try out a new surgical procedure on three-dimensional virtual patients.

After more than 20 years of research and exploration, virtual reality technology came out of the laboratory in the late 1980s and began to enter the practical stage. At present, a few developed countries in the world have begun to widely apply this high and new technology in the fields of economy, art and even military, and have achieved significant comprehensive benefits. According to foreign media reports, the U.S. Army's "Louisiana 94" combat exercise in 1994 was conducted using virtual reality technology. This exercise not only tested and demonstrated the doctrine, tactics and troop organization formulated by the US Army, making it more in line with the combat requirements of the 21st century, but also saved nearly 2 billion US dollars in exercise funds.

So, what is virtual reality technology? Simply put, it is a new technology in which people use computers to generate a realistic three-dimensional virtual environment and interact with it using sensing devices through natural skills. It is completely different from traditional simulation technology. It combines the simulation environment, visual system and simulation system into one, and uses sensing devices such as helmet-mounted displays, graphic glasses, data suits, stereo headphones, data gloves and foot pedals. Connect the operator with a computer-generated three-dimensional virtual environment. The operator interacts with the virtual environment through the sensor device, and can obtain multiple perceptions such as vision, hearing, and touch, and can change the "unintentional" virtual environment according to his or her own wishes. For example, the computer virtual environment is a building with various equipment and items inside. The operator will feel as if he is actually there. He can walk around the house to view, open and close doors, and move items through various sensing devices; the design of the house If you are not satisfied with the above, you can make changes at will. Obviously, it is much easier and cheaper to use this virtual reality technology to modify the design of buildings, machinery, weapons, etc., and implement technical operation training and military exercises.

Once virtual reality technology was applied, it showed people attractive prospects and was favored by the military circles of various countries. Since the early 1990s, the United States has taken the lead in using virtual reality technology in the military field, mainly in the following four aspects: First, virtual battlefield environment. That is, through the corresponding three-dimensional battlefield environment graphic image library, including combat backgrounds, battlefield scenes, various weapons and equipment, combat personnel, etc., a dangerous and almost real three-dimensional battlefield environment is created for users. To enhance their sense of presence and improve the quality of training. The second is to conduct individual soldier simulation training. Let soldiers put on data suits, helmet-mounted displays and data gloves, select different battlefield backgrounds by operating sensing devices, input different disposal plans, experience different combat effects, and then exercise and improve their technical level, just like participating in actual combat. Quick reaction ability and mental endurance. For example, the flight training simulator developed by the U.S. Air Force using virtual reality technology can produce visual control, process three-dimensional real-time interactive graphics, and have sounds and touches other than graphics. It can not only maneuver and control the aircraft in a normal way, but also process virtual reality. Various situations other than the aircraft, such as the threat of balloons, missile launch trajectories, etc.

The third is to implement joint exercises of various services and arms and establish a "virtual battlefield" so that both parties participating in the war can be in the same place. According to various situations and changes in the virtual environment, they can "dispatch troops", "fight wits and courage", and implement " "Real" confrontation exercises. The fourth is to conduct commander training. Virtual reality technology is used to synthesize a panoramic view of the battlefield based on reconnaissance intelligence data, allowing trained commanders to observe enemy and enemy forces and battlefield conditions through sensing devices in order to judge the enemy's situation and make correct decisions. The "Virtual Ship Combat Command Center" developed by the U.S. Navy can realistically simulate an environment that is almost completely similar to that of a real ship combat command center. The vivid visual, auditory and tactile effects allow trainees to immerse themselves in the "real" battlefield. superior.

Of course, virtual reality is still a young science and technology, and there are still many problems that need to be solved. For example, in a computer-generated virtual environment, every time the operator turns his head, the computer must update the three-dimensional image. Because the updated data is too large, the computer cannot complete real-time calculations. This causes system lag. For another example, there are differences between the visual motion signals generated by the US Air Force's virtual reality simulator and human feelings, which can easily cause headaches, dizziness, etc.

But no matter what, after all, virtual reality technology has opened up a new field full of development potential. It will become more and more perfect as time goes by, and its application in the military field will become more and more extensive, and its role will also increase. will get bigger and bigger.

Vitual Reality World

The emergence of World Wide Web (WWW) produced HyperText

Markup Language (HTML). In this way, text and graphics can be displayed simultaneously

Displayed in the same Page, and CGI (Common Gateway Interface)

can make the Web have stronger interactive functions. With the popularity of WWW and people's increasing awareness of the Web

To meet the ever-increasing demand, new Web languages ??need to be constantly produced.

The emergence of Java allows people to enjoy animations directly on WebPage.

The Java language is oriented to Object language, people can set animations on Page

and use Perl and C programming to generate executable code.

Currently popular text languages ??include HTML and SGML (Standard

Generalized Markup Language). They all use tags to describe

different elements in the data structure.

Recently, new Web languages ??have emerged. VRML (Virtual Reality

Modeling Language). It is a modeling language used to describe how a target object is presented on the Web. Like HTML, VRML is also

A description language that can be interpreted by the browser, but VRML is not described in the format of a

Page, but in the layout of a 3D environment and target.

The difference between HTML and VRML is the same as the difference between the blueprint of a building and its model.

1. What is virtual reality (VR)?

Virtual reality is a computer-simulated three-dimensional environment. Users can walk into this

environment and manipulate objects in the system. The most important and attractive thing about virtual reality

It is real-time and interactive. Through computer networks, multiple users can participate

in the same virtual world. The visual and auditory experience is the same as the real world, or even more gorgeous

Colorful.

What is described above is the future virtual reality world, and the current virtual reality system

is far from meeting people's requirements. First of all, the transmission speed of the network cannot be achieved

p>

Satisfy the real-time transmission of video and data exchange of large amounts of information; followed by virtual reality

The equipment used in reality is in the development stage and is far from being popularized.

2. Hardware equipment required for virtual reality

There is an essential difference between virtual reality and multimedia. Multimedia displays a series of two-dimensional images sequentially on the screen

, while virtual reality uses length, width and height, and

displays its three-dimensional image from all directions. Another important difference between the two is

hardware equipment.

Common computer interaction devices include keyboard, mouse, operating buttons, etc.

A multimedia system (Keyboard, Mouse,

Computer and Mounted Display is composed of a monitor and a speaker) ). There are several types of trackers: mechanical, supernatural, magnetic induction, optical and passive. Their dexterity is far superior to ordinary interactive devices. The "helmet" consists of a display, optical system, stereo sound box and tracking system

Into.

3. Examples of existing network virtual reality systems

1. SIMNET It is a system used for military exercises and is a member of the US military

Created to reduce the cost of training tank units. SIMNET is the first large-scale implementation of networked VR, which can adjust nearly 1,000 full-motion image models. .

2. VR games Many game companies have partially implemented virtual reality in their products

The real environment, especially on the local area network, makes real-time and interactivity a reality

.

4. VR Language

VRML (Virtual Reality Modeling Language) provides specifications for the establishment of virtual

environments and integrates The scene description language of existing 3D software

has the advantages of language. It has basic elements, vertices, line and surface definitions, coordinate transformation

Scaling, Rotation ) and translation,

and has optimized data structure.

5. VRML browser

If VRML is a language, obviously The VRML browser is

its interpreter. Indeed, the main function of the VRML browser is to read the VRML code

file and interpret it into a graphic image.

Currently there are many types of VRML browser software, such as Netscape's

Live3D

(scape/prod/products/navigator/

live3d/index ), WebFX by Paper Sofare

(paperinc/), SGI and Template Graphics

WebSpace by Sofare

(webspace.sgi/WebSpace/WhatsNew/ ),

InterVista Software's World View

(webmaster/vrml/) and Microsoft's

Virtual Explorer

(microsoft /windows/ie/vrml) and so on.

They basically implement the transformation effects of objects, such as lighting, perspective change, blur

blur, cropping, shadow, projection, collision ?觳Badger?

6. Create VRML files

The basic objects of VRML language are: sphere, cone, cylinder, cube

, text, etc. It provides convenience for creating scenes, such as the following example of creating a sphere.

# VRML V1.0 ASCII

Separator {

Material { diffuse Color 1 0 0 }

# the color red

Sphere { }

}

There are many Modeling software that creates VRML files reduces people's fear of the VRML

language, and there are many software that can convert other three-dimensional format files

into VRML files, such as 3DS, RAW etc.

it.sohu/web

course/webmonkey/1multimedia/vrml/