X3D - Page 3

Andrew Starling

September 16, 2002

Let's immediately bite into an example. This comes from http://www.web3d.org/TaskGroups/x3d/translation/examples/contents.html, a page hidden away in the deep recesses of the Web3D site.

<?xml version="1.0" encoding="UTF-8"?>

<!DOCTYPE X3D PUBLIC 
  "http://www.web3D.org/TaskGroups/x3d/translation/x3d-compact.dtd"

       "/www.web3D.org/TaskGroups/x3d/translation/x3d-compact.dtd">

<X3D> 

<head> 

<meta name='filename' content='geometryExample.x3d'/> 

<meta name='author' content='Don Brutzman'/> 

<meta name='created' content='8 July 2000'/> 

<meta name='revised' content='5 January 2001'/> 

<meta name='url' 
  content='http://www.web3D.org/TaskGroups/x3d/translation/
  	examples/course/geometryExample.x3d'/> 

<meta name='description' content='User-modifiable example to 
  examine the role of the geometry tag. See what nodes 
  can be replaced: geometry (no) and Cylinder (yes).'/> 

<meta name='generator' 
  content='X3D-Edit, http://www.web3D.org/TaskGroups/x3d/
  	translation/README.X3D-Edit.html'/> 

</head> 

<Scene> 

<Shape> 

<Appearance> 

<Material diffuseColor='0 .5 1'/> 

</Appearance> 

<Cylinder/> 

</Shape> 

</Scene> 

</X3D>

The example is a bit top-heavy with meta content, but in a larger file that wouldn't be so noticeable. The lower section that creates the shape itself is simpler than it would be in VRML. It's also pretty standard XML. Note the Cylinder element has a slash at the end rather than at the beginning, so is self-contained and exists as one tag rather than two.

We haven't space here to go into the details of all the differences between VRML and X3D, but here's broad-brush comparison, plus a few extra features of X3D.

X3D has a modular structure that allows small X3D players (plug-ins) to be used for simple X3D files. This level is called core profile or X3D-1, and overcomes one of the big problems that plagued VRML - the need for a fully featured player when looking at a reduced-feature file. Now, a simple file should be viewable on a small player.

For extra functionality, more components (profiles) can be added to the X3D player, until we reach the X3D-2 level where all VRML functions are covered. This means an X3D-2 player can also understand VRML. And in reverse, a VRML player can read X3D-2, and its less demanding sibling X3D-1, though only through a process of file conversion.

Other (optional) profiles can extend X3D's capabilities beyond VRML. This is the "extensible" element of Extensible 3D.

Other features:

Open source, so no licensing issues.
Has been officially incorporated within the MPEG-4 multimedia standard.
Compatible with the next generation of graphics files - Scalable Vector Graphics (SVG).
3D objects can be manipulated in C or C++, as well as Java.

Atmosphere

Adobe's surprise entry into the 3D market has been well received. Atmosphere allows non-specialists to create 3D worlds and avatars within them. One of its best features is its simple ease of use - the idea is to attract users who found previous 3D programs too difficult. It also has some cool features for multi-user environments, including a simple chat mechanism.

None of this is especially new. Products for creating 3D worlds have been around since 1996 and they've all been commercial failures. But Atmosphere may succeed where the others failed because it's so much better. Apart from its simplicity, the other big scoring point is that Atmosphere worlds are viewed using the excellent Viewpoint plug-in (Adobe has an investment in Viewpoint). Viewpoint is arguably the best of the plug-ins and has found its way into marketing of big brands such as Sony and Dell. There was even talk of a deal with AOL and incorporation within the AOL browser.

The chances of Atmosphere succeeding largely depend on whether the communities meeting in 3D Atmosphere worlds prosper, and that's why Adobe kept the program free for so long - to get these worlds above a threshold level.

More sophisticated uses, beyond marketing campaigns and chat environments, are unlikely because the only script that can be added to Atmosphere worlds is JavaScript, and although that's fine for basic animations, it's not enough for a complicated game environment. For that, developers are more likely to turn to X3D and Java or C++.