Setting up a VRML browser as a helper application is not difficult, it just requires a slight alteration to the configuration files of the HTML browser, so that it knows what to do when it encounters a file of the VRML MIME type. For example, to make the VRweb VRML browser a helper application for Netscape on a UNIX system, the following line should be added to the .mailcap file in the user's home directory (or the system wide mailcap file).
x-world/x-vrml; vrweb -URL %u %s
The exact instructions for installing and configuring for a specific browser can be obtained at the site from where the product is downloaded.
i3D is a free VRML browser for the SGI platform. It works by translating the VRML into its own i3D scene description file format. Version 1.0 supports WWWAnchor and WWWInline partially. SGI RGB is the only accepted file format for texture images. Gzipped files are decompressed. The software has many of the features of a high speed VR system, such as, time-critical rendering, navigation using spaceball or mouse, and stereo vision with CrystalEyes LCD shutter glasses. i3D needs to be configured as a helper application.
Figure 3-1 i3D (47K)
VRScout is a stand-alone VRML browser for Microsoft Windows from Chaco Communications. Version 1.1 runs on Windows 3.1, NT and 95, using Intel's 3DR rendering software. VRScout supports the entire VRML 1.0 specification, including WWWAnchor, WWWInline objects and textures. Textures can be in GIF, JPEG and BMP formats. The user can navigate through the scene in Walk, Fly or Examiner viewing modes. Gzipped and zipped files are decompressed automatically.
Figure 3-2 VRScout (98K)
As can be seen from the list above, VRweb is supported on Microsoft Windows and a wide range on UNIX platforms. Ports are currently under way for the Macintosh 68000 and Power PC. All are implemented using the Mesa graphics library, which does not utilize or require any special graphics hardware, and so can be quite slow. However, an OpenGL version, which does take advantage of any graphics hardware, is available for the SGI, DEC Alpha and Windows NT and 95 platforms. The source code has also been made available.
The latest UNIX version of VRweb supports most VRML features, including WWWAnchor, texturing (in-file texture images only) and Level-Of-Detail. VRweb 1.1 does not yet implement WWWInline objects. The user has a choice of five different navigation modes (Flip, Walk, Fly, Fly-To and Heads-Up) and can select the type of rendering required, from wireframe to full textured smooth shading. VRweb needs to be set up as a helper application.
Figure 3-3 VRweb (for SGI) (95K)
The WebFX Plugin is a popular VRML browser for the PC platform. Unlike the other browsers described in this section, it is an embedded viewer, with the 3D scene displayed within the window of the HTML web browser application. WebFX will only work correctly with one HTML browser, and that is Netscape Navigator version 2.0. It is fully compliant with VRML 1.0, including WWWAnchor, nested WWWInlines, Level-Of-Detail and textures. Textures can be in GIF, JPEG, and BMP formats. WebFX also supports GZIP decompression and some Open Inventor nodes.
There are three navigation modes: Walking, Flying and Pointing, using a mixture of mouse and keyboard input. Exploration of the 3D scene is aided by collision detection and selection between predefined viewpoints. It is also one of the fastest Windows based VRML browsers.
Figure 3-4 WebFX Plugin for Netscape (58K)
WebView is a free standalone VRML browser for SGI systems. SDSC have released it with full source code, as a public platform for the development of the VRML specification. The source code needs to be compiled after downloading.
WebView supports both VRML 1.0 and Open Inventor 2.0, the latter to allow the testing of experimental extensions to VRML. The most recent release is still Beta, so there are still some bugs and missing features.
There are four viewing modes: Examiner, Fly, Plane and Walk. A useful feature is a dialog box which gives the coordinates of the current viewpoint, such information can be helpful when building VRML worlds. WebView supports WWWInline and WWWAnchor nodes but cannot load gzipped files. External texture image files must be in the SGI RGB format and in the same directory as the VRML file.
Figure 3-5 WebView (69K)
WebSpace was one of the first VRML browsers to become available, and remains the favoured choice for the Silicon Graphics' workstations. It supports its own HTTP communication so can work standalone as well as an external viewer to an HTML web browser. WebSpace is 100% VRML 1.0 compliant. Features supported include WWWAnchor, WWWInline, Level-Of-Detail, textures (JPEG, GIF and Silicon Graphics RGB formats), GZIP decompression and also Open Inventor nodes. The user can begin to view and move around the scene while WWWInline objects are being loaded. A 'Smoothest Motion' option enables quicker and smoother movement through the scene by rendering with less detail, utilizing the VRML Level-Of-Detail where possible.
WebSpace has two navigation modes: Walk and Examiner. Both have an on-screen simulated dashboard, Walk mode has a joystick (see Figure 3-6), Examiner has a simulated trackball. Movement is enabled by interacting with these controls using the mouse, alternatively the keyboard can be used. There is also point and seek navigation option. If multiple viewpoints are defined in the original VRML file, WebSpace gives the user the option of moving automatically between the viewpoints, thus simulating a 'guided tour'.
Figure 3-6 WebSpace (annotated) (95K)
WorldView was the first VRML browser for Windows. It is able to work in standalone mode, or as a helper application for a HTML browser. Version 0.9g supports WWWAnchor, nested WWWInline, Level-Of-Detail, GZIP decompression and textures in GIF, JPEG and BMP formats. There are two navigation modes: Fly and Inspect. On-screen buttons are used to move around the 3D scene.
Reviews of the different VRML browsers, mostly for the PC platform, can be found at the following URLs:
Graphics Multimedia Virtual Environments Visualisation Contents