VRML

VRML is abbreviation for Virtual Reality Modelling Language. It lets you put three dimensional, interactive worlds on web pages. VRML is, in the words of the VRML Consortium, "an open standard for 3D multimedia and shared virtual worlds on the Internet", is a scene description language that describes the geometry and behavior of a 3D scene or "world". Web3D is the new name for VRML.

VRML was recognized as an international standard (ISO/IEC-14772-1:1997) by the International Organization for Standardization (ISO) and the International Electrotechnical Commission (IEC) in December, 1997.

VRML worlds can be single files or groups of files that load at the same time. They can range from simple objects to very complex scenes, scripted in a plain UTF-8 or ASCII (a subset of the UTF-8 character set) text file. A VRML file may be compressed using gzip, a freely available utility, and may be created, viewed, and edited in any plain text editor.

Vertices and edges for a 3D polygon can be specified along with the surface color, UV mapped textures, shininess, transparency, and so on. URLs can be associated with graphical components so that a web browser might fetch a web-page or a new VRML file from the Internet when the user clicks on the specific graphical component. Animations, sounds, lighting, and other aspects of the virtual world can interact with the user or may be triggered by external events such as timers. A special Script Node allows the addition of program code (e.g., written in Java or JavaScript (ECMAScript)) to a VRML file.

The MIME type of a VRML file is "model/vrml", although some servers may deliver it as the older MIME type "x-world/x-vrml". The spec requires VRML browsers to support both MIME types. If you administer a web server, you should use the official type, not the older "x-" type.

VRML files are commonly called "worlds" and have the *.wrl extension (for example island.wrl). Although VRML worlds use a text format they may often be compressed using gzip so that they transfer over the internet more quickly (some gzip compressed files use the *.wrz extension). Many 3D modeling programs can save objects and scenes in VRML format.

The plug-in to view these is widely available in many platforms.

Features of VRML (as specified on 1.0 version)

• Standard objects (cube, sphere, cone, cylinder, text)
• Arbitrary objects (surfaces, linesets, pointsets)
• Ability to fly through, walk through, examine scenes
• Lights
• Cameras (viewpoints)
• Textures on objects
• Clickable links
• Define and reuse objects

Altough VRML 1.0 worlds are static, with introduction of VRML 2.0 worlds can move and interact with the visitor to those worlds.

VRML 2.0 Features:

• Animated objects
• Switches
• Sensors
• Scripts (Java or JavaScript) for behaviors
• Interpolators (color, position, orientation, etc.)
• Extrusions
• Background colors and textures
• Sound (.wav and MIDI)
• Animated textures
• Event routing
• Define and reuse objects and behaviors and effectively add new nodes to the language with PROTO and EXTERNPROTO

Another very important difference is that VRML 97 is an international spec approved by the International Organization for Standards: ISO/IEC-14772-1:1997.

The first line of every VRML 97 file starts with:

      #VRML V2.0 utf8

and the first line of every VRML 1.0 file starts with:

      #VRML V1.0 ascii

Many, but not all, VRML 97 browsers will read and properly render VRML 1.0 files. No VRML 1.0 browser will read and properly render VRML 97 files. Furthermore, VRML 97 becomes VRML 2.0 standard.

Here is the sample of VRML script...

#VRML V2.0 utf8
# Red cone

Shape {
appearance Appearance {
 material Material {
   diffuseColor 1 0 0
 }
}
geometry Cone {
 bottomRadius 0.75
 height 1.6
}
}

VRML Specification is available from http://www.vrml.org/Specifications/. For more information, visit VRML FAQ @ comp.lang.vrml

Please note that VRML is obsolete standard and now has been superseded by X3D (ISO/IEC 19775-1)

Internet Filter

Internet filtering is the process by which some websites or applications that use the internet are allowed to work, whereas others are not. For example, many organizations tend to block access to a variety of websites, such that anyone attempting to go to these websites will not be able to do so. Other organizations may block services they feel are inappropriate or waste resources, such as online gaming, peer 2 peer file sharing, voice over ip, or other protocols.

A large and growing number of organizations choose to filter their user’s access to the internet. In the united states, this is especially prevalent in schools and libraries, as there is a federal mandate that requires schools and libraries to filter their user’s internet. If a school or library chooses not to filter, they risk lose federal finding, Although filtering is required by schools, there are no specific standards as to what must be filtered. Some schools don’t really want to filter, whereas others take charge and filter more than is required by law.

Many workplaces choose to filter internet access to shield themselves from liability, to reduce non-productive personal internet usage, or to reduce the usage of expensive internet bandwidth. Sometimes internet service providers (isp’s) choose to filter internet access. This usually happens for one of two reasons. First, it could be at the request of the customer, who does not want their children viewing inappropriate material on the internet. AOL’s parental controls are an example of this kind of filtering. The second common kind of ISP filtering is known as packet shaping. What this does is slow down or block access to certain protocols on the internet, rather than blocking particular websites. This is especially common in colleges and some cable modem networks, where peer 2 peer file sharing can consume large amounts of expensive internet capacity.