|www.alzado.net Vectorial Elevation|
|Relational Architecture 4|
Vectorial Elevation consists of a network of computers that process user requests on a first-come first-serve basis. Here are the different technologies involved:
The user reaches www.alzado.net and www.lyonelevation.net via a fixed IP address from NumériCABLE, our telecom partner and sponsor. They installed a 10Mbps cable connection in the control room at the Hotel Royal as well as three connections to webcams located around the city.
The web server is a Linux/Apache box behind a firewall. The server runs a queue programmed in perl and shell, serves pages and applets, relays video and sends emails to participants.
To participate the user downloads a Java applet that allows for real time 3D visualization of VRML files without the need for browser plug-ins in the vast majority of platforms. Arquimedia in Madrid modelled the virtual world and the applet was programmed by APR in Edmonton. When the participant submits a request the applet sends the exact x, y and z coordinates of each of the 18 virtual searchlights, as well as user information such as name, location and comments. The server queues this request.
When a request reaches the head of the queue, the data is sent to a 3D DMX application. This application knows the exact 3D position of each searchlight thanks to a calibration performed with differential GPS units and traditional surveying. The DMX application sends appropriate DMX commands over serial cable to the 18 Syncrolite SX7K searchlights to direct them to the desired location. The SX7Ks are new-generation 7kW xenon robotic fixtures that produce a very collimated lightbeam.
When the searchlights produce the participant's design four Axis webcams take digital pictures from the Royal Lyon Hotel, the Basilica, the Hôtel Dieu, and the Maison de Lyon. The images are watermarked with the participant's information using a custom-made application. As soon as the pictures are taken, a web page is built for the participant and an email is sent to him or her with its URL.
A user may view his or her web page by entering the personal code or by typing the URL in a web browser. The personal page contains the real and virtual images of the user's design as well as their name, location, date, time and comments.
A Java applet allows visitors to see the four project cameras in real time and shows an aerial view of the city. The video is subtitled with the name and location of the participant whose design is currently in the sky.
© Rafael Lozano-Hemmer, 1999 - 2003