VRML Notebook

VRML 1.0 Information Page Contents

1.0 Review of VRML Browsers

1.1 RECOMMENDED BROWSERS

The VRML Repository currently displays the Lab's worlds following the VRML 1.0 standard. Since many of our worlds are converted Open Inventor files, some additional nodes which are not part of the VRML 1.0 standard are also included in our .wrl files. We have found that the following recommended browsers best take advantage of our additional nodes. Specifically, the model, Environment, and Background nodes are all handled satisfactorily in these browsers. We recieved significant support for our decisions from the founding members of the VRML Architecture Group. We associate with this group on VRML decisions and are following the development progress of the VRML 2.0 standard. Many of our worlds have had animation incorporated in them at some point in time. The VRML 2.0 standard, when it brings the Moving World's proposal to fruition, will allow us to include the animation in our worlds. At that time, we will recommend the best VRML 2.0 based browsers for viewing our worlds. To date, only SGI and Sony have released alpha versions of VRML 2.0 browsers to the public.

1.1.1. SGI IRIX

  • Webspace (Silicon Graphics, Inc.) -- Webspace displays our worlds well on the Silicon Graphics' machines. We do most of our testing on an Onyx machine located in our lab. A few of our worlds use .gif texture files which have a background pixel color defined for transparency. Webspace does not support this transparency. Webspace does support the Fog node which we have and will continue to use for effect in some of our worlds.

    1.1.2. Windows NT

  • Live 3D (Paper, Inc.) -- The Live 3D plug-in for Netscape works well for viewing our worlds. We have enjoyed testing with Live 3D since we have had to do little editing of our Open Inventor based files. For example, Live 3D ignores the Environment nodes that it does not understand and that are not part of the VRML 1.0 standard. Live 3D supports the transparency effect that Webspace does not. And, Live 3D would allow us to implement some basic animation effects without waiting for the VRML 2.0 standard and related browsers to be made available.

    1.1.3. Windows 3.x

  • none -- The HIT Lab has had little success in using VRML browsers on the Windows 3.1 platform. And, given the number of complaints and problems voiced in the alt.lang.vrml and comp.lang.vrml newsgroups, we decided early to bypass testing on these platforms. Should society as a whole vehemently reject Windows 95, we will revisit testing on the Windows 3.1 platform. We don't expect this to happen.

    1.1.4. Macintosh

  • none -- The HIT Lab has many Macintosh computers. Just recently, we have seen support for the Mac version of Live 3D. We have read that it works satisfactorily, but not as well as the Windows' version. We are not aware of any other VRML browsers for the Mac.

    1.2 OTHER BROWSERS

  • VR Scout -- We received significant support for VR Scout as a VRML browser from our inquiries of other experts. But, upon our testing, we found that VR Scout did not handle gracefully neither our Environment nodes, nor our model nodes. We did not find the interface as simple to use as Live 3D's.

    2.0 VRML Conversion FAQ

    2.1 DESCRIPTIONS OF FILE FORMATS

    .dxfData Interchange Format (AutoDesk). The industry standard for describing geometry with color. Includes layer and block (instance) data.
    .3ds3D Studio (Autodesk). Geometry, colors, lights, and advanced material descriptions.
    [wire]Alias format. Geometry, colors, lights, and advanced material descriptions.
    .lpLightscape Preparation file. Geometry, colors, lights, and advanced material descriptions.
    .lsLightscape Solutiotion file. Radiosity mesh plus textures.
    .ivInventor file format (SGI). Preserves much of above file information.
    .wrlVRML (Virtual Reality Modeling Language). A subset of inventor files, for use on World Wide Web

    2.2 DIAGRAM OF FILE TRANSLATIONS

    Diagram of File Translations

    2.3 FILE CONVERSIONS

    FromTo Utility or DescriptionComments
    .dxf.lpload .dxf in Lightscape
    .lp.lslsrad or render solution in Lightscape
    .ls.ivls2iv utilityby Lightscape
    .dxf[wire]load .dxf in Alias
    [wire].dxfexport .dxf in Aliastexture and light info lost
    [wire].ivsave in Alias???
    .dxf.3dsload .dxf in 3D Studio2-D data lost
    .dxf.ivDxfToIvSGI utility, takes line and text data
    .3ds.dxfsave .dxf in 3D Studiotexture and light info lost
    .3ds.iv3dsToIvSGI utility, use only one material per object
    .iv.wrlivToVRMLSGI utility
    .3ds.wrlAutodesk or WCVT2POVtexture info lost
    .dxf.wrlWCVT2POV

    3.0 Miscellaneous Facts and Tips

    3.1 HITL UTILITIES

    There are a couple of really handy utilities developed at the HIT Lab which we've used when creating VRML files. They are not currently available to the Web community, but please contact us if you are interested in using them. Given enough interest, we' ll probably make them available for general use.

  • cameraPosition - records a participant's current camera position and orientation in a VRML file and prints to standard output. This information can then be inserted into the VRML file as a camera position
  • ivPrimCount - counts the primitives in a scene graph (inventor, but could be modified for VRML files), such as points, lines, and triangles.

    3.2 TEXTURES

  • Most browsers accept .gif and .rgb files for texures. SGI's .rgb format is 24-bit, which allows richer colors, but yields larger files than .gif files.
  • Frame rates are fastest if the resolution of textures is a power of two (256x256, 128x64, etc).
  • We have not been able to render .rgba files (with a "transparent" alpha channel) successfully in VRML browsers. However, we've experienced, with Live3d (Paper, Inc.), that .gif files with transparency assigned to one color actually render that color as transparent. Thus, this technique can be used to mask out irregular shapes on polygons.
  • Using Webspace (SGI), the textures are applied by default using the model field set to BLEND. This means that if polygons darken as their normals point away from the camera (typical), then the textures darken, too, as this occurs. By adding a field to each texture note such that its value is DECAL, however, the textures are rendered their true color independent of the value that the polygon is being rendered.

    3.3 ENVIRONMENT

  • If a VRML file with an Environment node is loaded into Webspace, and that node specifies a fog (or haze, or smoke, etc)., then Webspace does not clear this setting when new VRML files are loaded. We recommend that an environment node with atmosphere set to NONE be added to VRML files to force Webspace to not render fog in that file.

    4.0 Conversion of Files to VRML 2.0

    We will not be converting our files from VRML 1.0 to VRML 2.0 until we are ready to add behaviors to our worlds. We will provide a review of VRML 2.0 browsers and conversion utilites in Bruce Campbell's Conversion Diary.

    • Authored and edited by: