A Tablet Based Immersive Architectural Design Tool Ross Tredinnick Lee Anderson Brian Ries Victoria Interrante University of Minnesota D’Nardo Colucci, Ph.D The Elumenati, llc, Minneapolis, MN Abstract In this paper we describe a SketchUp VR system in which we create a hybrid two-dimensional / three-dimensional immersive architectural design system. This system combines a tablet PC, an optically tracked room, a display wall, a SpaceTraveler motion controller, and stereographic eyewear to allow immersive conceptual design and walkthrough using a version of SketchUp that has been enhanced with Ruby plug-ins. The tablet PC provides a ”sketchpad” type of user interface for SketchUp, while the tracked space and display wall enable the designer simultaneously to design at full (or any other) scale in an immersive (VR) environment. Introduction Both traditional and immersive design paradigms have their advantages and Traditional D modeling applications disadvantages that will be discussed prior provide a screen-based paradigm, to describing our hybrid system. whereby an architectural model exists A typical modeling application includes within a window on a flat display screen. viewing tools that facilitate designing More recently, advancements in virtual at a wide range of scales. To place new environment technology have triggered the geometry in the environment at a distant emergence of a new paradigm, known as location from the current viewpoint, a immersive architectural design (Anderson camera pan tool quickly shifts the center 00). Immersive architectural design of design to the necessary location. On programs utilize virtual reality hardware, the other hand, designers can modify tiny such as a HMD, to place the designer’s details of an intricate model by zooming in viewpoint inside of the model. Geometry and focusing the center of design on small creation and manipulation takes place by areas of a model. way of a three-dimensional input device. 8 Despite this practical functionality changes requiring precise movements for changing views, some downfalls exist may be difficult with a three-dimensional for the desktop design paradigm. The input device. Finally, a three-dimensional designer using a modeling application user interface must be considered to is performing a highly integrative act, avoid awkwardly re-introducing a two- attempting to create an environment dimensional user interface into a supposed with a strong physical three-dimensional three-dimensional environment. presence. Designing with the inherently In this paper, we introduce SketchUp two-dimensional desktop interface, limits VR, which attempts to combine the better the design process. Modeling applications features of the screen-based and virtual- effectively limit the viewing angle and based design paradigms. The system joins provide only limited screen resolution, several pieces of virtual environment which tends to objectify the design space, hardware together with a tablet PC to leading to a focus on external form rather create a hybrid system for design. We build than inhabitable space. The design may be the software system upon the popular also be negatively affected by the display SketchUp modeling application. SketchUp screen, with and its strong vertical and contains a built-in Ruby application horizontal edges and fixed aspect ratio. programming interface, which we use The emergence of virtual reality to extend SketchUp to be an immersive technology introduced a new possibility design application. The user employs for architectural design. Immersive SketchUp on a tablet PC to create designs, architectural design places the designer while simultaneously being immersed within the environment of the model, in virtual environment. All changes to giving a realistic sense of scale and the SketchUp model are simultaneously presence. This design method has the changed in the virtual environment. potential for overcoming several of the negative aspects of the desktop paradigm. Related Work For example, a dynamically changing viewpoint exists, often with stereo viewing, Advancements of virtual environment which leads to a greater sensation of technology triggered a change in the way presence of the inhabitable space being we can interact with a software program. designed. Although immersive modeling Virtual environment researchers adhere to may seem more beneficial than traditional this important idea everyday by designing desktop based programs, problems systems that allow three-dimensional emerge here as well. First of all, navigation immersive interaction. Architectural design becomes more of an issue. Placing new has become a very popular area in terms geometry in the model at a distant of immersive technologies and many location from the current focus requires immersive modeling systems have been an intuitive, easy form of navigation. Also, designed and tested (Butterworth 99), the modification of small details may (Donath and Regenbrecht 996), (Mine require additional viewing tools to zoom 997a), (Mine et al. 997b), (Forsberg in on locations, which may feel unintuitive et al. 998), (Donath et al. 999), (Hill within a head mounted display. Small detail et al. 999), (Regenbrecht et al. 000), Tredinnick, Anderson, Ries, Interrante, Colucci A Tablet Based Immersive Architectural Design Tool 9 (Dave 2001), (Anderson et al. 2003). In SketchUp. Unlike their system and also like addition, much research has gone into previous differences, our work renders understanding how digital technology through a projection-based display rather advancements can benefit the conceptual than a head mounted display. design stage in architecture (Campbell and Wells 1994), (Bowman 1996), (Bridges The Hardware System and Charitos 1997), (Bowman et al. 1998), (Kukimoto et al. 1999), (Lau and Maher Our hybrid system combines several 2000), (Schnable et al. 2001), (de Vries et al. pieces of virtual environment technology 2001), (Schnable 2002). to create an immersive design area. There has been a fair amount of The total system consists of an optical literature about combining the two- tracking system, a curved display wall, dimensional design metaphor into the three PCs, one tablet PC, a 3D Connexion three-dimensional virtual environment. SpaceTraveler, and Crystal Eyes 3D stereo The majority of previous work done in glasses, two stereo emitters. I will discuss this area combines a tracked clipboard how each feature fits into the system or drawing pad with a tracked pen stylus. below. The system is shown in action in The 3Draw system introduced such a user figure 1. interface (Sachs et al. 1991). Their system allowed three-dimensional sketching Tracking System of splines to model objects. Unlike our system, their work was not immersive, The room that holds our project and interaction occurred through a plain contains a Hi-Ball 3000 wide area optical desktop monitor. Since then, various tracker (Welsh et al. 1999). We mount the systems have combined a tracked ceiling of our room with several infrared clipboard and pen within a head mounted light emitting diode strips that allow a display environment (Angus and Sowizral HiBall sensor to calculate position and 1995), (Bowman et al. 1998), (Schmalsteig orientation. The total amount of tracked et al. 1999), (Chen et al. 2004). Our space roughly measures thirty feet by work differs from this work in two main twenty four feet. The system provides respects: first of all, our system runs on a projection-based display rather than a head mounted or workbench display; and secondly, interaction occurs through an actual tablet PC running windows and SketchUp rather than a tracked clipboard. Another piece of significant work that has some commonalities with our system is the worlds in miniature system (Stoakley et al. 1995). Like their system, our tablet PC contains a de-coupled camera viewpoint from the display wall and Figure 1. A student works on an apartment model manipulation of objects may occur through using the system. ACADIA 2006: Synthetic Landscapes Digital Exchange 330 Digital Dissemination: Dissemination and Representation updates to a Hi-Ball sensor at a rate of AMD Athlon 6 X Dual Core 800+ PCs 500-800 Hz. We mount a Hi-Ball sensor on with gigabyte of RAM compliment the top of a basic white construction helmet three projectors. Each PC holds a NVidia that the designer wears. The tracking Quadro FX 500 graphics card with 5 system provides position and orientation MB of video memory. The graphics cards information for our software system and are supplemented with NVidia gSync dynamically updates the layout of the cards to enable proper stereo viewing. virtual scene based on current position Figure three shows the display wall. The and view direction toward the screen. The display wall provides the immersive three- HiBall sensor transmits information over dimensional stereoscopic display of the wire to a CIB box that knows the layout architectural design system. of the system on the ceiling and converts the data to a point that represents Tablet PC position and a quaternion that represents orientation. To transfer tracking data We run the SketchUp program between the CIB and our software system, and our accompanying software on a we interface with the VRPN software Toshiba Portégé tablet PC. The tablet PC library (Taylor II et al, 00). Figure two contains an Intel Pentium M .00 gigahertz shows a picture containing a portion of processor with gigabyte of RAM. The the tracking system. user interfaces with the tablet PC by directly applying its accompanying pen Display Wall stylus to the screen. The use of a tablet PC provides mobility within the immersive The room contains a curved display environment. wall, back projected by three Christie Mirage 000 stereoscopic projectors. The Spacetraveler wall measures eight feet tall by twenty four feet wide and has a total display area of We optionally accompany the system thirty feet by eight feet. The wall viewing with a D Connexion SpaceTraveler. angle measures roughly 8 degrees. Three The SpaceTraveler interfaces with the Figure 2. A picture of the diode strips for the optical HiBall tracking system mounted on the ceiling in our lab. Figure 3.