Basic VRML Animation
By Andrea L. Ames
Many VRML sites include a lot of motion and interaction. Take the SGI site, for example, and that whimsical, animated character Floops.(See "
Online".) Ignoring the audio for the moment and concentrating on the animation and user interaction, what happens when you view the latest episode in the Floops saga?
After Floops has finished downloading, nothing happens until you click on some portion of Floops or his VRML environment, at which point Floops begins to move around.
Authoring Animation
Now, try to see Floops from an author's perspective. First, you build Floops using the Floops geometry, then you animate him with VRML animation. This animation usually consists of the following components:
- A named sender node (often a timer) that sends a message, or "event."
- A named receiver node that receives the event from the sender node.
- A route upon which the event travels from sender to receiver.
- Matching data types between the sender's
eventOut and the receiver's eventIn (the fields within the sender and receiver nodes that respectively send and receive the event); if types do not match, you must convert them.
To build a successful animation, you must create each of these components, as follows:
Name nodes to send and receive events.
