The augmented reality system enables engineers, architects, builders and developers adopt collaborative design techniques via data-intensive, 3D and digital modelling. The entry, manipulation and viewing and reviewing of design data is radically transformed.
Augmented reality (AR) or mixed reality research aims to develop technologies that allow users to mix or overlay the real world with computer generated 2D or 3D virtual objects. Unlike virtual reality that replaces the physical world, AR enhances the physical reality by integrating virtual objects into the physical world as we see it.
The ARTHUR project (Augmented Round Table for Architecture and Urban Planning), funded by the Information Society Technologies programme, enhances the table where design meetings are held. Virtual objects are projected onto the workspace through state-of-the-art Head Mounted Displays (HMDs) designed by project partner SaabTech. Using real world items to represent and manipulate these virtual objects, users can interact with the virtual model of buildings and cityscapes. So a cup or a pen would represent and become the 'placeholder' for a virtual building or part of one.
Why such a system?
Large sums of money may be spent on designing and constructing new buildings. The need for architects, engineers, construction experts, local government and urban planning officials to all contribute to building design, can result in a labour and time intensive project lifecycle involving many meetings. Yet these meetings are milestones in the design process without which no project can succeed.
Project coordinator Dr Wolfgang Broll from the Fraunhofer Institute for Applied Information Technology explains: "Changes to a design are normally made based upon drawings, physical models or animations. Therein lies one of the major problems of today's design process: All of these require a substantial amount of work and time before they have been realised. Usually, changes will be decided upon in a meeting, but the final decision and rendering of that change might well have to be postponed until the next meeting, when a sketch or model has been completed."
The ARTHUR interface marks a major change in the design process by dramatically reducing the design cycle. Working with the architectural firms Linie4 and Foster and partners, the researchers hope to be able to demonstrate significant savings with their forthcoming prototype for large and small firms alike.
The system's building blocks
The main system components include a multi-user augmented reality environment, a new personal HMD, the use of computer vision to track real world items and user gestures, the realisation of intuitive interaction mechanisms for multi-user AR, and the integration of the approach in existing CAD and simulation software.
The multi-user AR environment developed by Fraunhofer FIT allows multiple users to share a virtual space projected into their common working environment. While in general the participants see and interact with the same virtual objects, personal menus and individual additional information can be provided to each user.
Besides viewing quality (resolution, brightness, etc.), ergonomic design issues have been incorporated into the new HMDs guaranteeing comfort.
The system also includes another very important feature essential for efficient collaboration, the ability to see other participants' eyes during a session - usually not a feature of other displays.
Computer vision techniques, created by Aalborg University, use head mounted and/or fixed cameras to track the movements of real world items (placeholder objects, 3D pointers etc.) and recognise gestures. Due to the computer vision-based approach users can interact without being disturbed by cables or sensors connected to interface elements.
Tangible interfaces, wands (3D pointers) and gesture recognition are used to enable intuitive user interaction mechanisms. The Graphical Reality Augmentation Interface Language (GRAIL) designed by University College London, allows users to use these mechanisms to set-up their own interactive application scenarios. Thus users may grab a real world placeholder object, associate the item with a virtual object and thereby create a direct manipulation interface. Users may also select and manipulate virtual objects by a wand or use gesture input to pop-up menus, select items and execute actions.
The system will allow users to easily integrate its visualisation and interaction capabilities with existing professional or special purpose software. Integration with solar gain simulation programmes, space planning simulation software and commercial CAD software is currently incorporated. The CAD software integration is particularly useful in reducing the design lifecycle, as it prevents the need for agreed changes at the round-table meetings to be input twice.
In contrast to 3D environments such as CAVEs (Cave Automatic Virtual Environment), where the user is completely immersed in a virtual reality theatre, the ARTHUR environment is based on lightweight components. This enables portability and is ultimately wearable. Combining these location independent features with the emerging ubiquitous network access allows users to use the ARTHUR environment almost anywhere and anytime. This allows even unscheduled spontaneous meetings to take place. The location independent and easy-to-use environment permits non-expert users as well as inexperienced customers to use interactive 3D enhanced applications within their usual coordination and negotiation process.
Planning the future
The project addresses a wide area of possible collaborative applications with a focus on architecture and urban planning. However, the system may well be applied to all types of planning. For example, it could be used to plan new transport links and industrial plants. It could even be used in film pre-production, by large-scale event organisers, for simulation and learning environments and disaster relief management.
The ARTHUR team will be demonstrating their prototype application in September at the Interact exhibition in Zürich.
Dr Wolfgang Broll
FIT - Fraunhofer Institute for Applied Information Technology
D-53754 Sankt Augustin
Source: Based on information from ARTHUR