Augmenting Virtual Prototyping with Physical Objects Virtu Halttunen, Tuomo Tuikka HCI & Group Technology Laboratory Department of Information Processing Science University of Oulu, Oulu, Finland +358-(0)8-5531900
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[email protected] ABSTRACT We define virtual prototype as a functional, photo realistic, and three dimensional digital model of a future hand held electronics product. Besides visualisation, product concept designers need to know the physical attributes of the product, such as dimensions, weight and surface texture. WebShaman Digiloop system augments digital virtual prototypes with physical objects in order to support such tangibility. A data glove is used to manipulate the virtual prototype and a physical mock-up of a concept prototype adds the physical aspects of the product concept to the virtual prototype. The user of this system can examine the functionality and features of the product concept as well as feel the dimensions, weight and texture, and move the prototype freely in physical space.
Keywords Virtual Prototype, Concept Design, Tangibility
1.
INTRODUCTION
Our research domain is the product concept design of hand held telecommunications devices. This field requires collaborative organisation that brings together specialists like industrial designers and electronics, mechanical and software engineers. These individuals must cross disciplinary boundaries when relaying information and ideas about the product concept to each other.
distribution, and the possibility for functional representation of the concept, it is desirable to combine different techniques to find a solution that brings the physical and the virtual worlds together. One area where something similar to this has been accomplished is augmented reality where virtual objects are used to add information to real world phenomena. We decided to try a somewhat opposite approach, augmenting the virtual prototype with a real physical object. Combining physical objects and digital environments had been previously discussed in [1], and we believed they could be used to support each other, although other alternatives, such as the virtual workbench [5], exist.
2.
WEBSHAMAN DIGILOOP
Our idea was to link together a digital virtual prototype visualisation and a physical artifact so that the physical artifact would be ÔcoveredÕ by a virtual prototype. We decided to use an off-the-shelf personal computer workstation to study the speed and feasibility of our future system. This was challenging: how to make the hand, physical mock-up and virtual prototype to visually work together for the user. In our test system which we call WebShaman
Virtual prototyping is a promising technology to help the designers express their views, as it provides a common framework the designers can relate to [2]. It employs what we call Õsmart virtual prototypes,Õ three dimensional and photorealistic computer models of the product concepts that also have the functionality of the future product. These prototypes are also very useful when the designers are geographically distributed, since they can be shared over the Internet for a synchronous evaluation and design session [4]. However, virtual prototypes, being purely digital information lack tangibility - the physical properties that are essential for the designers, such as dimensions, weight or surface texture. In our studies about concept design we found out that physical objects such as pens, spoons or bottles were often used t o support argumentation and help the designers act out their ideas about the possible usage of the future device [3]. Because there are benefits from using virtual prototypes i n concept design, such as faster software development,
Figure 1: WebShaman Digiloop system
Digiloop we chose to combine these elements with a flat panel display, a data glove and a position tracking sensor. Figure 1 shows WebShaman DigiLoop in action. The user wears the data glove (Virtual Technologies CyberGlove) in one hand, and uses the other to hold a physical mock-up of the product concept. A position tracker sensor is used to track both the data glove and the mock-up. A flat panel display i s positioned between the user and the work area where the prototype is manipulated, acting as a ÔloopÕ into the virtual world. User's hand is tracked to provide a way to visually point at the prototype, and to make direct manipulation of the prototype with the data glove possible. The finger and wrist joint angles are read from the data glove, and the hand i s represented with a digital model, similar to the virtual prototype. The system calculates the collisions between the hand model and the buttons of the virtual prototype, and triggers appropriate actions in prototype. Likewise, the position of the physical mock-up is linked to the virtual prototype. Moving the mock-up behind the display moves the virtual prototype correspondingly. This setup of equipment and our software aims at creating the feeling of using a finalised concept in the Digiloop. User's hand moves in the space behind the display screen giving an impression of 3D digital world where the hand belongs. The physical object provides a real feeling of the concept dimensions, weight and material. At the same time on the screen the hand representation ÔtouchesÕ the virtual prototype following the path of the real hand. Mock-up dimensions restrict the virtual hand while giving a real feedback to the user. Obviously, there are limitations to this system. The current setup requires that the user's head remains relatively still because we do not track the head position in relation to the screen. Therefore, the image seen on the display may not be a totally accurate representation of the position and viewing angle of the prototype and the hand. However, since the prototype and the hand move in the same coordinate space, their respective positions mirror the real world situation. At the moment, we did not find tracking both the user's head and the display and using this additional data to calculate the appropriate viewing angle worth the effort and increased amount of computation. Moreover, the current system can only be used with button kind of controls in the prototype. The accurate calculation necessary for sliders, rollers, or opening covers is not a trivial task, and we wanted the system to be as fast as possible when tracking the physical object with the virtual prototype. Our combination of virtual prototyping techniques and the physical object introduces a new way to use a user interface. On one hand, a physical object is used to augment the use of virtual prototype and not vice versa. Virtual prototype, on the other hand, is a digital object that has properties that can ultimately be included into the final product. It combines a photorealistic visual representation of the design object and the functionality that simulates the actions of the final product.
3.
LESSONS LEARNED
There certainly still are issues to be considered in order t o make an evaluation of a future concept with WebShaman
Digiloop in a flexible design situation. It addresses, however, an important problem for product concept design; how t o introduce tangibility to systems that support this specific work [3]. We have augmented the virtual prototyping technology with physical objects, thus providing besides the tangibility also the functionality of the product for evaluation of new concepts. As such WebShaman Digiloop is a new kind of system, combining these two elements. It is a demonstration of concept, however, and therefore requires understanding as well as reflective discussion. The comfort of use could be better. Keeping a hand up for a long time is unpleasant. Thus, there should be more consideration on usability. Especially the glove calibration procedure takes both time and effort now, and an easier system should be developed. Also, the usability of the virtual prototype should be examined. Since this is the main argument for the whole experiment, we would need to know how the usability of virtual prototype and physical object corresponds to usability of a concept prototype. Is it possible to evaluate such usability from a digital representation, and if it is, what are the differences between WebShaman Digiloop system and a concept prototype? Other concern is that obviously many other issues than those presented in this paper affect the approval of designers. First, according to our studies a dynamic concept design session is a fast and innovative which in order to create new concepts derives resources from past of the design processes, and the designers. Juxtaposing the new concepts against old designs is a method used all the time by designers. Thus, the system should be able to support designers also in this kinds of tasks. Second, the users should be able to fluently exchange information between different technologies. No extra effort for creating virtual prototypes and using the system should be introduced, the users should be able to easily ÔjumpÕ into a collaborative design session and transfer information back and forth. Third, new user interfaces should be able to really benefit the designers in evaluating the concept. In the future work we will address these issues with concept designers from electronics industry.
4.
REFERENCES
[1] Brave, S., H. Ishii, et al. (1998). Tangible Interfaces for Remote Collaboration and Communication. CSCW '98, Seattle, WA, USA, ACM Press. [2] Rix, J., S. Haas, et al., Ed. (1995). Virtual Prototyping Ñ Virtual environments and the product design process. London, UK, Chapman&Hall. [3] Tuikka, T. and K. Kuutti (1999). Physical Space and Concretization of Ideas in Product Concept Design. 2nd International Workshop on Strategic Knowledge and Concept Formation, Morioka, Japan, [4] Tuikka, T. and M. Salmela (1999). ÒWebShaman: Shared Virtual Prototypes for Product Designers in the World Wide Web.Ó SIGGROUP Bulletin SIGGROUP Bulletin(April): 51-55. [5] vonWiegand, T. E., D. W. Schloerb, et al. (1999). ÒVirtual Workbench: Near-Field Virtual Environment System with Applications.Ó Presence 8(5): 492-519.
