SIGGRAPH 99 Sketch (Text Document)


Kelly B. Heaton and Robert D. Poor
Massachusetts Institute of Technology
20 Ames Street, E15-468
Cambridge, Massachusetts 02139 USA
kelly@media.mit.edu / r@media.mit.edu

Nami is a decentralized community of identical "orbs," each of which can display various hues of colored light, respond to touch and wirelessly communicate with its neighbors. A user activates the spread of color within Nami by touching a single orb, whereupon the selected orb will respond with the expression of a new color. The new state will be broadcast to neighboring orbs, prompting them to assume the color and forward the message. In this way, waves of colored light will move throughout the distributed network of Nami and create beautiful patterns of behavior. There is no "right" or "wrong" way to arrange Nami, as messages are relayed through whatever pathways are made possible by the placement of the individual orbs.1 The resulting combination of wireless communication, distributed networking, and various patterns of colored light provides a new means for graphical animation in the physical domain.

Computer Graphics in Sculpture

Computer-generated animations become possible when an artist can exercise dynamic control over a large quantity of individual pixels. Although a single changing pixel is uninteresting, increasing numbers of pixels will manifest recognizable patterns when subjected to certain recursive algorithms. These emergent behaviors can demonstrate life-like characteristics2, reminiscent of the spread of gossip within a community or the ripple of waves across a pond. Whereas traditional computer graphics are limited to the flat space of a screen or projection, the integration of color animation into a community of distributed objects denotes physical pixels, or "phyxels," whose behaviors are guided by the user's jurisdiction over a physical system. Phyxels can be imagined as game pieces, building blocks, bricks or other sculptural objects that can express mutable color in response to user input and network structure. While the ubiquitous "beige box" format of a computer limits an artist's ability to unite physical interface with virtual form, phyxels are free to integrate their computational properties with an appropriate tangible design. Like pixels, a phyxel is most interesting when treated as a unit from which an overall structure can be built; but whereas pixels can exhibit only virtual qualities, phyxels have both sculptural form and animated features.

First Implementation of Nami

The degrees of freedom necessary to transpose computer graphical behaviors onto a decentralized network of physical objects presented several challenges to the Nami project. Each orb must be able to (1) respond to the user; (2) exhibit the desired behavior; and (3), communicate with other orbs. Capacitive touch-sensing3 seemed the most intuitive interface for the Nami orbs, enabling the user to control an orb's state by simply cupping the domed top. Each orb has a microcontroller to manage user interactions and communication. A separate microcontroller modulates three LEDs (one each of red, green and blue) to create different mixtures of colored light. Considerable effort was put into creating a gentle and soothing blending of color, so that the orbs would have an organic aesthetic suitable to the wavelike behaviors from whence Nami derives its name. The physical appearance of the orbs is similarly designed to have an undulating form, reflective of the color waves that they carry.

Future Research

In the first iteration of Nami, orbs were designed for wireless communication over a limited distance within a plane; however, future research will investigate alternate designs for a network of distributed physical objects. The current Nami relies on fixed-format messaging for network communication; the next generation of Nami will employ "mobile agents"4 to provide messages that are executable software objects. This architecture will enhance design flexibility and make Nami a useful test-bed for the visualization of distributed networking algorithms. Several improvements are being made to the infrared communication and touch sensors, and an inductive charging scheme is under development. Forthcoming versions of Nami will also include an electronic artist's palette, intended to enhance user control by providing a method for specific color and pattern selection.


1 Robert Poor. Hyphos - A Self-Organizing Wireless Network. Master's Thesis, MIT Media Laboratory. 1997. http://www.media..mit.edu/~r/projects/hyphos/

2 Harold Abelson, Thomas F. Knight, Gerald Jay Sussman. Amorphous Computing. 1996.

3 Rehmi Post. Personal communications.

4 Nelson Minar, Kwindla Hultman Kramer, Pattie Maes. Cooperating Mobile Agents for Dynamic Network Routing. Chapter 12, Software Agents for Future Communications Systems, Springer-Verlag, 1999, ISBN 3-540-65578-6. http://www.media.mit.edu/nelson/research/routes-bookchapter/