Question:
What are the key features of Active VRML?
Answer:
Microsoft’s Active VRML, is a proposal built on top Microsoft’s Direct X suite of graphics/multimedia APIs, and also incorporates Microsoft’s Visual Basic Script, and Microsoft’s Reactive Behavior Modeling Language.
Active VRML allows OCX and OLE plug-ins which will give data access to the Microsoft world of applications. Active VRML is very different from the other proposals, because it is based on a functional-programming approach and uses nested functions. In fact, about all it has in common with the other proposals is that it can read and write VRML 1.0.
Active VRML comes with such a committed bundle of Microsoft products that one is left with the impression this is what Microsoft is doing, and the rest of the world can go with its consensus and see who prevails. Microsoft has its own Internet Explorer browser, its own VRML plug-in from Intervista, and its own world-builder from Caligari.
How far it will go with its own ActiveVRML will be interesting to see. Microsoft describes it as “a powerful open framework for the creation of animated and interactive multimedia worlds that can run on multiple platforms”. Active VRML can be extended by the use of code written in Java or Visual Basic or C++ or other languages. There will be an Internet Explorer Active VRML browser for Windows which will take advantage of Direct 3D and accelerator cards that work with it. Microsoft Internet Studio is integrating Active VRML with their tools for multimedia authoring.
The special features of Active VRML are:
- All objects implicitly vary with time, and time can be included as a parameter when describing an object’s behavior.
- Interactivity is built in because objects have reactivity and can switch from one time varying behavior to another.
- All media are equal, and therefore can be combined to form composite objects such as a shape with a sound that moves, or a shape with a moving surface.
- All existing file formats can be included inside Active VRML.
A unique feature is the specification of behavior by saying what should happen, not the steps by which it happens. Issues such as sampling rate, image resolution, and rendering quality are left to the browser to determine depending on the user’s system capabilities. Multi-user interactions are deliberately left out of this round of specification although Microsoft promises they will be in future releases.
Availability: Reference implementation in object and source code form sometime in mid 96. Licensed as free use of object and free use of source except for commercial purposes — a ‘reasonable’ rate to be charged for commercial use of source.
