GroupMorph A Group Collaboration Mode Approach to Shared 3D Virtual Environments for Produc

GroupMorph: A Group Collaboration Mode Approach to Shared 3D Virtual Environments for Product DesignJohn M. LinebargerLehigh UniversityDepartment of Computer Science and Engineering19 Memorial Drive WestBethlehem, PA 18015 USA1 610 974-1774jmlg@G. Drew KesslerLehigh UniversityDepartment of Computer Science and Engineering19 Memorial Drive WestBethlehem, PA 18015 USA1 610 758-4818dkessler@ABSTRACTVirtual reality technology is increasingly being applied to globally distributed teams engaged in collaborative product design. Observations of product design teams have suggested at least four distinct modes of collaboration—complementary, competitive, peer-to-peer, and leader-follower. Another insight from observation is that collaboration consists of fluid transitions between these modes in the completion of the design task, driven by a flexible process of subgrouping and regrouping which reflects the structure and progress of the task. Yet most collaborative virtual environment systems support only one mode of collaboration—peer-to-peer—and those that do explicitly support multiple modes (or even individual roles) do not allow fluid transitions between them in the context of the same task. In addition, no explicit support is provided to allow subgroups to be formed and dissolved. To address this problem, a collaborative virtual environment (CVE) for product design that supports multiple collaboration modes and fluid transitions is proposed; two metaphors for collaborative product design (collaboration tree and infinitely recursive conference room) are introduced; the use of a collaboration tree interface widget is detailed; and the Simple Shared Virtual Environment (SSVE) toolkit for collaborative virtual environments is described.KeywordsCollaborative virtual environments, distributed virtual reality, computer supported cooperative work, collaborative product design, models of collaboration, group collaboration modes.1.INTRODUCTIONBecause the flexibility and plasticity of software models provides an economic advantage over physical models, especially when multiple iterations are required, product design has increasingly adopted a virtual prototyping process. Collaborative virtual environments have played a role in this process, generally in the design review stage. But as design teams become more globally distributed, the use of virtual environments earlier in the design process is being explored because of the shared mental models that such environments provide.2.GROUP COLLABORATION MODES2.1Case Study ObservedA recent product design competition was held at Lehigh University. The charter was to create (via assembly from prefabricated parts) a toy car according to several cost and performance criteria. Here’s the experience of one design team: •After a period of inactivity, one woman took the initiative and assembled a complete car while otherteam members looked on and made comments.•The car was performance-tested, and suggestions for improvement fell into upper and lower body categories.The car was separated into chassis and top and given totwo separate subgroups of the team for redesign.•After reassembling the car, more performance tests were conducted. This time a disagreement arose abouthow to remove a fundamental design flaw. The car wasduplicated and given to two competing subgroups.•The product of each subgroup was tested and one was selected to represent the final result of the entire team.To describe the process outlined above, the concept of group collaboration modes for product design is introduced in Table 1:Table 1. Group Collaboration ModesName Type Description Peer-to-Peer BehaviorAll team members contributeequallyLeader-Follower BehaviorOne team member functions asleader Complementary FormationTask is divided and assigned tocomplementary subgroups Competitive FormationTask is duplicated and assignedto competing subgroupsPermission to make digital or hard copies of all or part of this work for personal or classroom use is granted without fee provided that copies arenot made or distributed for profit or commercial advantage and that copies bear this notice and the full citation on the first page. To copy otherwise, or republish, to post on servers or to redistribute to lists, requires prior specific permission and/or a fee.Copyright is held by the author/owner(s).CVE’02,September 30–October 2, 2002, Bonn, Germany.ACM 1-58113-489-4/02/0009.These modes illustrate the collaborative functioning of the group, not individuals in the group, and can be divided into two types. Formation modes describe the reason why a subgroup was formed, and behavior modes depict how a subgroup is behaving. For group collaboration modes in another domain, see [1].2.2 Case Study AnalyzedThe case study of the four-person design team above is analyzed pictorially (using and/or trees) in Figure 1 in terms of group collaboration modes. The following observations can be made: Collaboration consists of fluid transitions from one mode to another in pursuit of a common goal; subgroup formation defines an interface and is recursive in nature; and in some sense, the subgroup formation process reflects the structure of the task (inthis case, the car being created).Leader-FollowerPeer-to-Peer3. CVE SUPPORT FOR GROUPSMost collaborative virtual environment systems support only one mode of group collaboration—peer-to-peer. Those that do explicitly support multiple modes (or even individual roles) do not allow fluid transitions between them in the context of the same project or task (e.g., the CALVIN system [2]). In addition, no explicit support is provided which allows subgroups to be formed and dissolved to reflect the structure and progress of the collaborative task. The concept of formations [3] comes closest; it treats groups as first class objects and presumably uses the third party object mechanism of the MASSIVE system [4]. However, formations coalesce around objects, not tasks, and to date have not been used in a fluidly recursive fashion for design.4. GROUPMORPH CVEThe GroupMorph collaborative virtual environment is currently being developed at Lehigh University to support group collaboration in product design tasks. In the spirit of the worlds-in-miniature (WIM) widget [5], it uses task-in-miniature widgets to represent and manipulate two different metaphors for product design. The first is the collaboration tree, depicted in Figure 2 for a hypothetical example in a six-person design team. As a widget it would be used for awareness, navigation, subgrouping and regrouping, and object transfer. The second in some ways is its inverse, the infinitely recursive conference room, portrayed in Figure 3. Breakout rooms are themselves conference rooms with a table in the center and breakout rooms on the side.5. SIMPLE SHARED VE (SSVE)GroupMorph is implemented using the Shared Simple Virtual Environment (SSVE), a multi-user extension to the Shared Virtual Environment (SVE) library [6]. Threaded peer-to-peer CORBA servers in each session are used for both TCP and UDP multicast communication, and objects are replicated locally.Figure 2: Collaboration Tree MetaphorFigure 1: Stages of Collaboration in the Case StudyFigure 3: Infinitely Recursive Conference Room Metaphor Because of its novel group support widgets, we believe that GroupMorph will better facilitate design team collaboration in a shared 3D virtual environment, and plan to demonstrate this through experimental trials. Relevant metrics include time, cost, and quality of the design, as well as subjective perception.6. REFERENCES[1] Maher, Mary Lou, Anna Cicognani, and Simeon Simoff.“An Experimental Study of Computer MediatedCollaborative Design.” International Journal of Design Computing 1 (1997-1998).[2] Leigh, J., A. Johnson, and T. DeFanti. “CALVIN: anImmersimedia Design Environment Utilizing Heterogeneous Perspectives.” IEEE Computer Graphics and Applications 16, No. 4 (July 1996): 47-51.[3] Lloyd, Dave, Steve Benford, and Chris Greenhalgh.“Formations: Explicit Group Support in Collaborative Virtual Environments.” Proceedings of VRST’99, 162-163.[4] Benford, S.D., and C.M. Greenhalgh. “Introducing ThirdParty Objects into the Spatial Model of Interaction.” Proceedings of ECSCW’97, 189-204.[5] Stoakley, Richard, Matthew J. Conway, and Randy Pausch.“Virtual Reality on a WIM: Interactive Worlds in Miniature.” Proceedings of CHI’95, 265-272.[6] Kessler, G. Drew, Doug A. Bowman, and Larry F. Hodges.“The Simple Virtual Environment Library: An Extensible Framework for Building VE Applications.” Presence 9, No. 2 (April 2000): 187-208.。