Generative Interfaces and
Scenarios for Intelligent Architecture
A Framework for Computer Integrated Buildings
Chair for Computer Aided Architectural Design CAAD, Institute of Building Technology, Department of Architecture, Swiss Federal School of Technology, Zurich, Switzerland.
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New media and modern building automation have a strong impact on contemporary architecture. So far one could regard built architecture as static. These new technologies allow a dynamic impulse to architecture. The objective of our research work is to demonstrate the impact of innovative systems on architecture in daily usage while providing building automation, multimedia integration and facility management services in intelligent networked buildings. Its focus is the integration of Internet based technologies and its open and scalable standards into buildings.
Figure 1 Lab setup of the Red Hell. On the left image is the Red Hell with a projection of a scenographical spatial design exercise showing the connection of the real space with its representation. On the right side is the control panel for the Red Hell and the control space
This paper introduces a lab that is used both in teaching and research. The lab is running on the level of a state of the art functional prototype and comprises a complex infrastructure. This lab called Red Hell was constructed as a portal for the teleimmersion research project ‘blue-c’ at the Swiss Federal Institute of Technology [1-2]. A red-colored wooden frame defines the architectural space of the Red Hell and embeds the complete technical infrastructure. This infrastructure is composed of multimedia and building automation elements.
The operation of buildings is one of the main research focuses of the chair of Computer Aided Architectural Design (CAAD) guided by Prof. Dr. Ludger Hovestadt . Next to its primary task in the blue-c research project, the Red Hell works as a demonstration prototype providing services like automation, security, media control, access control and data completely through Internet based technologies. This paper describes the systematical approach we have followed to build up a software framework which controls all these services and the implementation of this framework within the architectural curriculum of a second year course in the field of CAAD.
1.1 The Computer Integrated Building
In building technology we differentiate until today the whole area of building automation from the area of communication. In both fields dedicated devices have been used to provide the respective functions. Building automation comprises light control, heating, ventilation and air conditioning (HVAC), etc. The telephone, the radio and the television, etc, represent the communication components in a building context. Until the mid-eighties dedicated devices have been used to provide these specific functions. In the nineties bus systems like EIB in Europe and LON in the USA appeared and allowed the development of multifunctional systems regrouping different functions of building automation in one system.
The used bus systems could not handle the required data traffic needed in the communication area. The appearance of Ethernet and the rise of the Internet created the base for integrated communication systems. Based on this new technology, services like Voice over IP, video on demand or web radios could be established and spread worldwide at low cost.
Frank Duffy predicted already in 1991, that both fields of building automation and building communication would merge together to a computer-integrated-building (CIB) beyond 1995 . This vision has not yet been achieved and there is no standard available. There are numerous approaches coming both from the field of building automation and the field of information technology. We implemented the concept of Frank Duffy in a working prototype. This prototype is used in teaching and research and is constantly extended. We used Internet technologies to integrate automation and communication into the building. The focus of our work is to show the possibilities and the impact to architecture resulting from such a system from the architectural point of view.
Figure 2 Diagram derived from Frank Duffy’s vision of a computer-integrated-building (CIB) of 1991 
The framework implemented in the lab is a system architecture based on three layers. The bottom layer consists of generic hardware. The middle layer encapsulates the hardware into software services which can be accessed by the top layer. The function of the top layer is to allow the interaction of the user with the Red Hell.
2.1 Hardware - Multimedia and Building Automation
The bottom layer contains generic hardware, a group of sensors and actuators. Typical sensors are buttons, motion detectors or input devices. Typical actuators are lights, video devices, audio devices or projectors.
We prefer devices which can be controlled directly via Internet protocols like TCP/IP. If a device does not support direct control via IP we are using embedded systems to map the functions of the device and to provide them via IP to the system. For instance, the projector of the Red Hell can only be controlled via Infrared or RS-232. In this case we are using a computer and its RS-232 interface to integrate the projector into the system. All devices of building automation are managed with a RaumComputer building automation unit . The RaumComputer handles ten dimmable spotlights, five dimmable neon lamps and a window which can be electrically switched from opaque to transparent. The RaumComputer unit itself is providing an TCP/IP interface of all managed devices to the system.
Figure 3 System architecture
2.2 Service Management Platform
The middle layer, often called middleware, is a software layer. Software components are controlling and managing the hardware elements of the bottom layer. As far as possible the communication of the software with the underlying hardware layer is based on Internet protocols, Internet technologies and bus systems. A bus system is the standard communication medium used in the area of building automation. The approach used in the lab decouples the hardware elements of each other. A switch is no longer connected to a series of lights. It is a sensor in the hardware layer that sends only impulses to the middleware. The middleware receives the impulses of all sensors and is the only instance which is controlling the actuators.
This decoupling allows a free configuration and programming of the hardware and therefore allows an individual reaction to impulses from the hardware layer. The middleware is written in Java and is embedded in the OSGi framework which is a framework for deploying and executing service-oriented applications. The Open Services Gateway Initiative (OSGi) defines and promotes open specifications for the delivery of managed services into networked environments [6-7].
The middleware is providing again an interface to the top layer. This service application interface uses the exchange of XML messages for the communication between users and the middleware. The framework allows multiple users to be connected to the system at the same time. The messages are composed of request and notification messages. Users send requests to the system. The middleware reacts and sends the appropriate control commands to the hardware and a notification message to all listening clients.
2.3 User Interaction
The top layer builds the interface between the users of the architectural space of the Red Hell and the system implemented in the space. Arbitrary applications and therefore an arbitrary number of users can be connected with the system at the same time. For example, each time a lamp for example is switched, the impulse is transmitted to the middle layer. This event triggers the middleware to notify all connected/online user interfaces. As a consequence, all applications are up-to-date at any time. In an open and ubiquitous environment like this, an application can react on incoming notifications and interact with the lab individually.
This approach allows developing generic interfaces for the architectural space. The complete functionality of all devices in the Red Hell can be combined in and accessed through a single user interface. The total control of the interface allows defining the complexity of the interface. The projector itself has more than a hundred different functions. The interface designer can decide which of these functions will be accessible to the user. Another advantage is to combine easily different functions into scenarios within the interface. For example an interface button could be created which switches the projector on and dims all the lights down.
Although a single interface encapsulating all these functions can be realized, it is also possible to create a multimodal interface. The middleware has the possibility to get simultaneously inputs from multiple interfaces as well as from different input types like video tracking, gesture recognition, motion detection and ordinary light switches.
The choice of XML messages as intelligible exchange medium to the middleware permits the detachment of the front-end completely from the system. This allows an approach to develop a wide range of possible front-ends for the interaction. These can be web applications or stand alone solutions. A connection to the Internet and the ability to process XML data are the only two requirements a front-end application has to fulfill.
Figure 4 Touch screen interfaces of the Red Hell
For the Red Hell we have used Macromedia Flash because it allows creating XML socket connections and it is a simple development environment to build appealing graphical front-ends . Another advantage of Flash is that it creates interactive vector graphics which can be played on various numbers of devices and operating systems. We have implemented an interface for a touch screen which is installed as a control panel inside the Red Hell.
Besides research, the lab was used to teach 200 architectural students in building automation. The aim of the course was to teach the concept of the computer-integrated-building (CIB) to architects. We wanted them to understand the underlying technical principles and to let them discover the architectural potential of the realized prototype.
The students had to fulfill two tasks. They had to create an interface for the Red Hell in a first step. The second exercise consisted in a spatial scenographical design. Macromedia Flash was used as development tool to carry out both exercises.
3.1 Interface Design
The students were asked to design a graphical user interface for the lab. They were given a template which contained the XML communication with the Red Hell system. An example showed them how to control the devices in the Red Hell. The focus of the exercise was to think about interface issues. This comprised a design of an interface logic and to take an aesthetical position. The range of results varied from strictly graphical interactive images to ergonomic approaches and to playful solutions.
Figure 5 Examples of student works showing different interfaces for the Red Hell 
3.2 Spatial Scenographical Design
A spatial scenographical design had to be done as second exercise. This was achieved in a self running Flash animation which used the lab as a stage and which was projected on the screen inside the Red Hell. In this exercise we wanted students to grasp the potential of the idea of the computer-integrated-building. They had to play with all the devices of the space and create a dynamic, temporal and spatial scenario. Two technical approached could be taken to realize this task.
The first approach was to create an ongoing animation and send on defined key frames commands into the system. In this way it was possible to design an animation and, at the same time, control the different devices inside the Red Hell. Most students took this approach generating a wide range of spatial scenarios. Some students represented the lab in their animations and merged therefore the real space with its virtual representation. Other students created a small story and included the space into this narration.
Figure 6 Examples of student works showing different spatial scenarios for the Red Hell 
The second approach was to work with the notifications sent by the middleware which were broadcasted constantly to all listening clients. In this case the notifications were controlling the flow of the Flash animation. Any change in the Red Hell would alter the projection displayed in the space. These scenarios could than easily be controlled from the outside, for instance, with the touch screen interface which is permanently installed in the Red Hell. An example of this approach is the work of a group of students who mapped the status of each light with the image of a dancer (figure 7). The intensity was translated in the alpha value of the correspondent image. In this way each light condition would generate a different image on the projection screen.
Figure 7 Request and notification of the connected interfaces and spatial scenarios
The systematic approach to merge media and building technology is one of the main research topics of the Chair for CAAD. It is linked to several ongoing research projects. We believe that this concept of a computer-integrated-building will considerably extend the potential of architectural design. The architect will be able to include spatio-temporal considerations into a design project. Architects will have the facility not only to design physical spaces but also to design the interfaces for them.
We would like to thank all the architectural students of the second year course in CAAD 2003/04 for their participation and their work. A special thank goes to Christian Spagno from the center of product design who helped with the construction of the Red Hell and to Prof. Dr. Ludger Hovestadt head of the CAAD chair at ETH Zurich.
 Gross M., Wuermlin W., Naef M., Lamboray E., Spagno C., Kunz A., Koller-Meier E., Svoboda T., Van Gool L., Lang S., Strehlke K., Vande Moere A., and Staadt O. 2003. Blue-c: A spatially immersive display and 3D video portal for telepresence. In Proceeedings of the ACM SIGGRPAH 2003 Annual Conference. ACM Press, New York.
 Hall Richard, Cervantes Humberto. 2004. An OSGi Implementation and Experience Report. In Proceedings of CCNC 2004. Las Vegas, Nevada USA
 The Interfaces shown as examples have been designed by Basil Georg Spiess, Marc Zürcher, Tobias Klauser, Tim Sergej Kop, Simon Martin Edelmann, Boris Gusic Daniel Abraha, Michael Martin Bühler, Willy Urs Stähelin, Martin Andreas Jacob Staubli, Mathias Uhr
 The spatial scenarios shown as examples have been created by Tobias Klauser, Tim Sergej Kop, Philippe Markus Lacher, Lukas Peter Raeber, Reto Giovanoli, Franziska Pfyffer, Damaris Baumann, Sabine Laura Herzog, Julia Annika Sulzer, Fabian José Valverde