For example a Proximity Sensor is used to cause an event when the user is inside the area defined by the sensor. A sound describing an object plays when the viewer moves close to that object as illustrated in Figure 2. An overhead view of line with proximity sensors. Triggers can be used for more than playing sounds clips. They can cause a speech synthesizer to read text, print Braille, and via programmed external utilities execute virtually any type of code.
Triggers can initiate the execution of arbitrary code and direct devices to perform desired actions.
In Figure 3 we see, in an overhead view of the entire assembly line, the bounding boxes of the four proximity sensors. When the viewer's position enters any of these volumes the appropriate audio is triggered. An overhead view of line with proximity sensors. The audio in VRML is also spatialized a feature we have not taken advantage of yet. However sounds can be associated directly with object and triggered as deemed appropriate.