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Application of User-Centred Design and Metaphor in User Interface Design

The Emmy award-winning Boujou (pronounced "boojoo") was the first commercial automatic camera tracker. It calculates the position of a camera from image sequences alone and under most circumstances with no additional user intervention. This allows computer-generated images to be integrated with live motion footage much more quickly and accurately than before. The product is the result of a collaboration between the Oxford Metrics Group, which is already well-known for its Vicon Motion Capture system, and Oxford University's Visual Geometry Group. A new company, 2d3, was established specifically to undertake the development of the product, which started in 1999. Version 1 was released in 2001. (Further information is available at www.boujou.com)

Figure 1, boujou screen shot showing task view and goal-oriented dialog

A design goal for boujou was that it should require very little user intervention. However, if problems occur, guidance needs to be readily available, without users having to refer to documentation or a separate help system.

Syntagm was responsible for the conceptual and user interface design of boujou. We started by performing a competitive analysis of related products. We also had the chance to observe and interview a prospective user, who had experience of manual camera tracking products.

A tree-style hierarchical grouping of artifacts (see Figure 1) was already in use in at least one competing product. However, in the approach usually taken at that time, tree controls did not assist users in performing actions. Instead, once an action had been performed, any resulting artifact could be found under the appropriate branch of the tree. The design I proposed for boujou made several changes to the conventional use of the tree control, but without interfering with its usual operation:

A "Michelin Guide" metaphor was used to direct users to tasks that need to be performed (refer to the screen shot). A single diamond means "optional", two diamonds mean "typical" and three, "required". In addition, the tasks that should be considered now (as a consequence of the current state of the process) are highlighted with solid red diamonds, whereas diamonds for other tasks are hollow grey.

Tasks can be performed directly by either double-clicking or right-clicking on each heading. Double-clicking can be thought of as the long and scenic route, with an explanatory dialog appearing explaining the tasks and any relevant choices. Right-clicking is the direct route, with a simple popup menu of choices displayed.

Artifacts resulting from a task are shown under the appropriate task heading. They have a set of consistent operations that can be performed on them and an associated set of dialogs based on a common design.

The task view design has been a fundamental part of boujou since its early beta releases. This is what the lead customer-facing product specialist had to say about it:

People are usually very positive about the Taskview, especially when you show them the product for the first time. I think they like the idea of being gently reminded what they need to do next. It definitely helps people convert from other tracking software to boujou. Camera tracking is quite a daunting prospect for newcomers, and the Taskview helps to show people that they don't need to wade through huge, complicated manuals before they can track a shot.