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VRML (Virtual Reality)

VRML (Virtual Reality)


  • VRML Standards
  • VRML Code
  • Viewing VRML
  • Potential Applications

    • VRML Standards

    Virtual Reality Modeling Language is a standard protocol to describe and render three dimensional objects and scenes via the Internet. With VRML, it is possible to represent houses, museums, and other spatial structures. Virtual reality, like our everyday world, allows us to respond to visual and spatial cues such as the location of a light source, the texture of an object, and the speed of an approaching object, while, at the same time, linking to other resources on the internet.

    The draft specification for VRML 1.0 was released in October of 1994; the current standard is VRML 2.0. In addition the creating stationary 3D worlds, the latest version of VRML affords the moverment and sound by allowing designers to script behaviors with Java.

    Standards and Tutorials:

    VRML Code

    Here's a sample bit of code for defining a cube: 
    #VRML V1.0 ascii

    Separator {

    DEF SampleCube Separator {

                    Texture2 {
                            filename "checkerboard.jpg"
                    }

                    Translation {
                            translation 0 0 0
                    }

                    Cube {
                            width 10
                            height 5
                            depth 5
                    }
        }
    }

    • The first line of code identifies what follows as an ASCII VRML file conforming to Version 1.0 specifications. This information is mandatory.
    • The cube is named "SampleCube"; since VRML is object-oriented, once you create an object you can re-use it by refering to it by name.
    • VRML maps its environment onto a three-dimensional grid, defined by an (X, Y, Z) coordinate system (horizontal, vertical, depth). The "translation" values place the image at the origin coordinates: (0, 0, 0).
    • the cube's dimensions, 10 x 5 x 5 in this case, are also defined against this coordinate system. Because of this, VRML lends itself well to producing scale models of real-world environments.
    • the cube will have an image ("checkerboard.jpg") wrapped (or "texture mapped") around it. This is simply a standard .gif or .jpeg that the VRML browser uses to coat the surface of an object. As with Web pages, large numbers of texture maps will increase the file's loading time.
    • a more complex VRML world would consist of numerous nodes similar to this one, all within the same .wrl file. The word "Separator" at the top of the file would partition different groupings of a larger set of objects.

    VRML Authoring Tools:

    Viewing VRML

    VRML files are identified by a .wrl extension (for "world"). When such a file is encountered on the network, your Web browser will launch either its VRML plug-in or the stand-alone browser  defined in Netscape's Preferences.

    The VRML browser performs two basic functions: parsing and rendering. Parsing the .wrl file consists of reading the file's contents and verifying that they conform to the current VRML standard; flawed VRML code will not parse, and results in a blank screen or an error message. Once parsed, the .wrl file is then rendered by the browser, which means it interprets the code's description of the objects and scene, and then displays them graphically for the user.

    Though rendering quality can vary, most browsers present a similar interface. A control panel or dashboard allows the user to navigate in and around and behind objects in the environment. The brower also allows the user to rotate the scene, yielding multiple perspectives. Some browsers also allow the user to adjust the lighting within the environment, and mark favorite perspectives and visual angles.

    VRML Browsers:

    Web Sites using VRML:


    Potential Applications

    VRML may be used to recreate an historical environment. VRML is already being used as a visualization aid in the sciences and applications in the humanities are surely forthcoming. The Language Visualization and Multilayer Text Analysis project at Cornell, for example, draws upon CAD technology rather than VRML, but one can easily imagine VRML being used to produce similar results. Alternatively, VRML can be used to lend a textual database spatial structure, allowing the user to navigate among related constellations of texts.

     
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