DETC 2001 / CIE-21256 MULTI-USER MODELING OF NURBS-BASED OBJECTS

This paper presents MUG , a multi-user environment for collaborative conceptual shape design. The majority of current research prototypes and commercial systems for collaborative modeling emphasize data sharing and markup. Collaborative 3D environments and virtual worlds usually restrict themselves to models with display representations (e.g., VRML) and asynchronous sharing of distinct objects. Our MUG prototype enables collaborative modeling of individual shapes: multiple users, operating at a distance, working on the same design. In our current work, we have focused on collaborative shape modeling of NURBS—allowing users to select control points and concurrently manipulate the same entity. To achieve this functionality, we have developed a protocol for synchronous mathematical construction of NURBS forms. We have adopted a multi-client/single server architecture in which changes are synchronized at a collaboration server and propagated to the clients. Our implementation uses Sun Microsystems’ Java, along with the Java3D and JavaSpaces extensions. In addition, as part of this work, we have developed a Javabased NURBS library, as well as faceting and rendering routines specifically suited for a light-weight collaborative environment. We believe that as network connectivity continues to radically reshape the design process, we need to enable new design techniques based on intimately shared design spaces. We believe that our approach illustrates one channel in which collaborative engineering systems can be better integrated with collaborative work environments.