COLLABORATIVE ENGINEERING IN COMMON VIRTUAL REALITY ...

XVIІІ ННТК с международно участие „АДП-2009”

COLLABORATIVE ENGINEERING IN COMMON VIRTUAL REALITY ENVIRONMENTS Angel Bachvarov, Jurica Katicic, Yordan Yordanov Resume: This paper presents a brief overview on the Collaborative Engineering approach widely used recently for optimization and improvement of engineering and research activities. It considers the possibility for enhancement of Collaborative Engineering trough use of Virtual Reality environments and Virtual Engineering methods. Further, a possible solution for implementation of Collaborative Virtual Environment based on the IDO: Cooperate, a dedicated software module within the IC: IDO VDP platform is described and the found advantages, limitations and bottlenecks are discussed. Key words: Virtual Reality, Virtual Engineering, Collaborative Engineering 1. Introduction Due to the enormously fast developing information and communication technologies and the liberalization of the markets, the world is constantly becoming more and more globalized and interconnected. The product development process has changed tremendously in the last few decades. Nowadays it is unimaginable for the companies to develop complex products on their own: they concentrate on their key competencies and their suppliers have an increasingly important role for the development of the particular components. Because of the fierce competition and the shorter “time to market”-cycle of the products even the traditional engineering processes are distributed among more locations in order to make the most optimal use of the know-how, the competencies and resources in terms of time, quality and costs (or return of investment). 2. Brief Overview on the Collaborative Engineering In general, the engineering projects for solving real world problems involve use of a large number of components and the interaction of multiple technologies. The components included in the product are decided in an iterative design process. In each iteration, interfaces and interface conditions among these components are designed with slack to account for potential variations created when the components and interface values become better known. Iteration proceeds towards increasing detail. The design personnel may change, and their numbers expand with increasing level of detail. This complex nature of the engineering problems demands considerable communication and coordination between various participants [1]. Advances in computer technology and the Internet have created new types of external relationships among design engineers, developers, researchers and among entities. As a result of these advances, a new paradigm, called collaborative 489

XVIІІ ННТК с международно участие „АДП-2009” engineering, collaborative product development (CPD), or, the collaborative Enterprise has emerged. The Collaborative engineering, or CPD, is the application of team-collaboration practices to an organization’s total product development efforts. It builds upon the systems engineering, project/program management foundations of primarily in-house cross-functional product development teams introduced by concurrent engineering [2]. A structured framework of services and activities for applying Collaborative Engineering can be seen on Fig.1.

Fig. 1 A framework for applying Collaborative Engineering approach

3. Virtual Environment for Collaborative Engineering Especially, use of diverse Virtual Engineering (VE) methods is suitable for engineering and research collaboration, since its main goal is also the optimisation of the product development as a part of the product lifecycle. The means of VE to achieve this goal are models, simulations and mock-ups, thus data which can be exchanged and shared between different users via networks. The Collaborative Virtual Environments (CVEs) are computer-enabled, distributed virtual spaces in which persons can meet and interact with others, with agents and with virtual objects. Such VR environments enable inclusion through immersion of multiple users. CVE is tightly connected with such issues as networking and security. Good performances are achieved through usage of the User Datagram Protocol and multicasting [3]. Since the scene tree has to reform automatically and consistently during the collaborative session, following aspects have to be considered: real time membership and global scene merging, consistent real time operations, refreshment, 490

XVIІІ ННТК с международно участие „АДП-2009” consistent ownership transfer, security and address allocation and defined procedure by leaving [3]. The main task of the networking support is the monitoring of the state of the network [4]. For this purpose three types of tools are applied: tracing (e.g. ping), performance measurement and traffic simulation tools. A security problem arises from the fact that the distributed applications normally reside in different private networks which are protected by access lists and firewall technologies [4]. It can be solved through Virtual Private Networking (VPN), but in this case the support of VPN through different service providers and the transition from one to another service provider has to be previously checked. Another important statement regarding networking is that the traffic performance is time-dependent, i.e. the traffic rate varies during the different times of day, which is especially interesting for intercontinental co operations. The selection of an appropriate bandwidth for data transfer is also an important issue. 4. Implementation of VCE trough IDO: Cooperate Within an experiment carried out on the VR projection facilities of the Lifecycle Engineering Solutions Centre (LESC) at the University Karlsruhe, a VCR was tested based on the IDO: Cooperate module. This is an independent software module part of the Visual Decision Platform (VDP), developed by the German company IC: IDO. VDP represents a software infrastructure that unifies data integration, result management and the user interface of visual applications. It consists of an OS independent kernel and four major APIs surrounding it (see Fig. 2): (i) The application programming interface allows fast development of visual applications; (ii) The render programming interface is used to develop render plugins; (iii) The extractor programming interface is the base for the process integration, e.g. data exchange to CAD or PLM; (iv) The simulation programming interface allows integration of dynamic simulation packages. The kernel of VDP is running on Linux and Windows 32 and 64 bit. The kernel is distributable. IDO: Cooperate can be used in two modes: (i) Desktop VR and (ii) Immersive VR. In the first case several workstations simulate distributed virtual environment, enabling collaborative manipulation and control on the reviewed objects and scenes. In order to work in a “cooperative” mode, the clients need to start the IDO: Cooperate and connect to the cooperate server. Users enter their names, nicknames and the IP address of the server as well as a password and if the connection is successful the Status View pane populates with a list of all the currently connected clients as shown on Fig. 3. Usually one of the users opens or creates a scene in his/her working environment. From this point on changes on the workspace of one user are reflected in the workspaces of all the other users. Whatever changes are made to the objects of the scene all the participants receive the same exact view. A pair of glasses (used as presence metaphor) on the workspace corresponds to each user currently connected and is the user’s virtual presence in the scene. 491


Fig. 2 The Visual Decision Platform (VDP)

Fig. 3 The Status View pane of IDO:Cooperate

In Immersive VR mode two spatially distant located Immersive facilities are connected through IDO: Cooperate. The way of use is similar to the above described. The experiment for testing of CVR was carried out with a standard model of a helicopter cabin, prepared for use in the VDP as its native .ICB file format. This has been loaded and visualized in the IDO: Review module as usual. The IDO: Cooperate was used in both operating modes, Desktop VR and Immersive VR (see Fig. 4 and Fig.5).

Fig. 4 Different perspectives at the reviewed test model (Desktop CVR)

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Fig. 5 Different perspectives at the reviewed test model (Immersive CVR)

In result of the experiment some bottlenecks and limitations of the used software were found. (i) IDO: Cooperate was not capable of restricting each user’s manipulation rights on the objects. Thus, if many users try to move an object at the same time, unexpected results could occur since the object is not “locked” by the first user who tries to work on it and all users are able to do this concurrently; (ii) Further, operation within CVR was based on the “designing for two worlds” principle, as users were never fully immersed in it but are always partially in the real world too. No special requirements for the communication infrastructure in place were identified in order to work with IDO: Cooperate. Currently widespread commodity networks, especially Ethernet are far than enough to accomplish the implementation. Speed is not an important factor in the communication between the devices since as long as the scene is loaded on all the nodes, only the changes (or the “deltas”) are transferred to them, which dramatically reduces the load on the network. This means that currently available bandwidths will be sufficient. It is even possible to use the Internet to connect geographically disperse locations with clients on one continent and server on another, which is the main idea behind IDO: Cooperate VDP. Of course, latency here becomes essential since there should not be a significant delay in the time between an action performed by one user and the action being reflected on the workspaces of the other users. Latencies of up to 100-150ms are an acceptable value. Hence, dial-up networks are not suitable for this purpose since delays in such networks are rarely below 200ms. It is necessary to set up a secure connection between the nodes if the Internet is used. This is easily accomplished by using conventional VPN tunnels. On the base of the gained experience it is highly recommended to use IDO: Cooperate in conjunction with an already existing video-conference solution (e.g. Skype) in order to widen the communication channels between the participants involved within collaborative operations, which has been done within the experiment.

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XVIІІ ННТК с международно участие „АДП-2009” 5. Conclusion The ease with which CVR can be set up makes it very attractive for production and research entities or users who want to make use of its capabilities for connecting remote Virtual Reality environments for real time collaborative operations. The lack of special requirements or expensive equipment and the use of technologies that are currently in place are an important advantage of the tested IDO: Cooperate module. Unfortunately, it has some limitations related to the lack of restriction by collaborative manipulation of the virtual objects and scenes and the reached level of immersion. Notwithstanding this, IDO: Cooperate shall become an extremely important tool for intensification and enhancement of the research activities between LESC and the VR Lab of the Technical University of Sofia. References: 1. Siram, D. Computer Supported Collaborative Engineering, AAAI Technical Report WS-93-07, MIT, Cambridge, MA, USA, 2007. 2. Davis, J., Keys, K. etc. Collaborative Engineering for Research and Development, NASA/TM-2004-212965, IAMOT, Washington DC, USA, 2007. 3. Costantini F., Toinard C., Chevassus N., Secure mobile replication of collaborative virtual reality, Intelligent Multimedia Computing 2000, Neuer Hochschulschriftenverlag 2000, pp. 162-164 4. Hommes F., Pless E., Networking support for collaborative virtual reality projects in national, European and international context, Selected Papers from the TERENA Networking Conference 2004, 8 pp. Authors Data: Angel Bachvarov, Assist. Prof., Chair of Discrete Production Automation, Faculty of Mechanical Engineering, Technical University Sofia, Kliment-Ochridski 8, 1000 Sofia, Bulgaria; Phone +359 2 965 3790; е-mail: [email protected] Jurica Katicic, Research Associate, Institute for Information Management in Engineering (IMI), University of Karlsruhe, Adenauerring 20a, Building 50.41 (AVG), 76131 Karlsruhe, Germany; Phone +49 721 608 6654; e-mail: [email protected] Yordan Yordanov, IT Specialist and Network Administrator, Faculty of German Engineering Education and Industrial Management, Technical University of Sofia, Kliment-Ochridski 8, 1000 Sofia, Bulgaria; Phone +359 2 965 3790; е-mail: [email protected]

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