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.