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5.3.DESIGN RATIONALE AND DESIGN INTENT DOCUMENTATION

The transfer of the user interface design intent to a larger software development team can be largely accomplished through the use of high-fidelity interactive simulations. A simulation can capture the design intent more accurately than a paper text document (it readily expresses the “look and feel” of a product). A simulation unambiguously communicates the intended user interaction, graphics, fonts, animation, auditory prompts, and expected system response time. The simulation should also include a text window to annotate the design and record the high-level design principles, general design guidelines, and design rationale.

The key advantage to this method is that the user interface can be rapidly iterated without having to update a separate design specification document. Also, it is relatively easy to ensure consistency between the user interface design intent and the interface of the final product as it is being coded (these may progress concurrently). This will considerably shorten the development time for the product.

6. SUMMARY

The methods described in this chapter apply to the design of new-generation products. They are illustrated by a case study of a new wireless personal communication product called Orbitor. The Orbitor team had to determine the set of key user values and relevant product attributes and integrate these into a superior small, mobile communicator (see Figure 11.9). The list of potential features and services was long, but there were many constraints. The small display size, the need to use the product while mobile, and the limitations of multitasking identified in scenario-creation sessions meant the Orbitor could not be all things to all people.


Figure 11.9  Early model of Orbitor personal communicator

With new-generation design projects a multidisciplinary team determines the problem space and the customer values, while continuously evolving multiple design solutions. An Exploratory Stage precedes an Refinement and Analysis Stage so that the design team’s initial creative output is not overly constrained. Design is done in all stages (Exploratory, Refinement and Analysis, and Formal Design). The Danish scientist, Piet Hein, expressed it as follows: “Art is solving problems that cannot be formulated before they have been solved. The shaping of the question is part of the answer” (Ching, 1979).

User interaction scenarios are used in all three of these stages. Early-on, scenarios are used to facilitate communication and brainstorming in a multidisciplinary design team. They are later used to give users a view of the new product concepts in a particular task-based context. Finally, in the Formal Design Stage, scenarios are used in conjunction with paper prototypes to test detailed implementations of a user interface.

In the Formal Design Stage, the design effort is focused on articulating the users’ conceptual model; this is explicitly designed and tested through the use of scenarios in combination with prototypes. The conceptual model in the interface is primarily communicated to the user through interaction dialogue and the use of metaphors. Paper prototypes are later used to create a scripted high-fidelity simulation, and then a fully interactive highfidelity simulation is built. The interactive simulation is used for formal usability testing and also to communicate the user interface design intent to other project partners (e.g., software developers, hardware developers, marketers).

Interviews, focus group sessions, and usability testing are conducted throughout new-generation projects to support the iterative design process and validate the user interface as it evolves. Since user interface guidelines and style guides do not yet exist for advanced non-WIMP interfaces, these design projects tend to require more conceptual design time and more user input.

7. ACKNOWLEDGMENTS

The development of the Orbitor user interface was the joint effort of numerous individuals within the Corporate Design Group at Nortel Technology. In particular, the author wishes to acknowledge the effort of the other members of the UI design team: Brian Beaton for visual interaction design and Bruce Stalkie for simulation development. The author also wishes to thank Jeff Fairless, Des Ryan, Mike Atyeo, Gord Hopkins, Arnold Campbell, Peter Trussler, and John Tyson for the contributions they made to this paper.

8. REFERENCES

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