University of Washington Abstract Prolix A Text-based Participant System for VR by Mark Takacs August 17, 1993 Chairperson of Supervisory Committee: Professor Thomas A. Furness III Engineering (Inter-Engineering) Virtual Reality has captured the imagination of many people, yet few have experienced it directly due to the currently expensive display and sensor technologies. Those who have experienced virtual worlds often comment on the world's inability to maintain interest with prolonged use. The only thing that remains consistently interesting are other human users. Yet the number of users in a multi-participant world is realistically limited by the great cost of equipping each user with motion tracking sensors, head mounted audio and visual displays, input devices or other interface gear. This thesis presents a program called Prolix which allows access to the virtual worlds running at the Human Interface Technology Lab (HITLab) without the ex pensive interface equipment. Prolix assumes only a keyboard and a screen with vt100 capability. Input to the virtual world is accomplished via typed commands and cursor keys, while output appears as narrative text and a simple ASCII-character plan-view of the participant's immediate surroundings. The text interaction style uses the conventions and interface feel of internet Multi User Domains. (MUDs) An informal pilot study shows that Prolix provides a usable, effective and enjoyable way to communicate with others using the same access interface. Prolix successfully placed a text based person in two VR worlds, one with another immersive user, the other with another Prolix user. However, in the immersive setting, the Prolix user's graphical display was soon overwhelmed by the volume of information generated by the moving entities and needed to be frequently refreshed.