Antonio Eduardo Dias, Joao Pedro Silva and Antonio S. Camara
Virtual ecosystems are virtual worlds representing real ecosystems. Humans
have a limited perception of space and time and are poorly equipped to
handle the flow of information generated in such environments. This paper
focuses on the creation of an interface, BITS (Browsing In Time and Space),
that allows users to browse through such a complex virtual world, interact
with its objects and take notes. The pen and note-pad metaphor is used in
an intuitive way, replicating a real pen and note-pad. A new concept of the
use of this metaphor arises with the use of the space and time sliders.
Humans have a limited perception of time and space,
which means that only a
limited
amount of information can be processed during a certain period of time.
Therefore,
when immersed in a virtual world, important information can be missed or
forgotten by the user (Stytz et al., 1993).
BITS (Browsing in Time and Space)
is being developed to facilitate the user
exploration of two different virtual ecosystems: Coast, a sensory
ecological model (Dusenbery, 1992) of a coastal ecosystem (Fig. 1), and
Virtual Tejo, a macro exploration of an estuary. These two projects are
intended for EXPO'98, an Universal Exposition which will take place in
Lisbon.
Virtual ecosystems are virtual worlds representing real ecosystems. They
have the
following properties:
FIGURE 1: Using BITS in the Coast project.
BITS (Figure 2) includes four main distinct features:
a time slider, a space
slider,
object manipulation and note taking capabilities.
BITS relies upon the use of a real pen and a real note-pad.
Their positions
and
orientations are tracked using attached Polhemus sensors.
The use of a real
pen and
note-pad increases the realism of the metaphor, which
allows the use of the
system
even by unenlightened users (Hinkley et al., 1994).
The virtual pen will
never get through the virtual note-pad as the system
is using a real
note-pad and pen to manipulate the virtual
ones. Another possible solution would be to use force
feedback devices and =
an
accurate collision detection, which would be a considerably
more expensive
solution.
Often, the user arrives at a certain location and needs to
know the
simulation results for that place, at an earlier step.
This can be easily
achieved by moving the lock switch to the space position
and using the time
slider to travel in time while staying at the same place.
In environmental systems modeling it is often necessary
to know the
simulation results in different areas during the same
simulation step. The
complexity of these models does not enable the observation of the global
phenomena (Stytz et al., 1994). Thus, it is required to have a tool to
travel through space and register local effects of the simulation, during
the same time step.
One has two alternatives to achieve this goal, both requiring the lock
switch to be turned to the time position: navigate through the virtual
ecosystem using the Vball, a virtual six degrees
of freedom (6 DOF) device,
as described in the next subsection, or return to previously visited
locations by moving the space slider.
To navigate through the virtual ecosystem,
the user inserts the pen in the
Vball
and uses it as a 6 DOF joystick.
The ability to repeat operations and
interactions facilitates learning.
When the lock switch is off, the proposed time
and space sliders enable the
user to go back in the simulation, repeat it,
and even take different
actions during the repetition.
The user can select any object by activating
the pick button and using the
pen as a pointer. Using the pen inserted in
the Vball it becomes possible
to manipulate the selected object.
Logging is a normal activity in the editing
and/or analysis of time coded
documents (e.g., video and audio editing).
Real time annotation systems for
the analysis of video (Weber and Poon, 1994)
and audio documents (Whittaker
et al., 1994) have already proved to be useful for those purposes.
In virtual reality simulation, unlike the above
mentioned systems, there
are four dimensions: time (t) and the three space axes (x, y, z).
Therefore, annotation must be done in all of the
four dimensions (t and x,
y, z) to assist the user in accessing tagged key
steps of the simulation
process. BITS (Fig. 2) was developed to answer these requirements.
To allow the user to take notes in real time two
options were considered,
either through keyboard or pen interface. Although
most users type quickly
with a keyboard and it is easy to conduct searches
through the notes,
handwritten notes provide the user with the ability
of easily drawing
symbols and sketches (Whittaker et al., 1994).
At any time, the user can go back to a key simulation
step simply by using the
corresponding time and space referenced notes.
Extensive usability testing of BITS will be made
as well as an attempt to
generalize its principles to non-environmental
applications. One important
improvement will be to provide the user with
the possibility of taking
video shots and voice annotations during the simulation.
We also intend to
let the user see and hear like the natural objects under observation
(Downer, 1988).
The work of Antonio Eduardo Dias is funded by Junta Nacional de
Investigacao Cientifica e Tecnologica (JNICT) through a PhD
fellowship. The
project is funded by JNICT grant no. PEAM/C/GAG/143/93.
Abstract:
Keywords:
Virtual reality, Pen-based input, Metaphors, User interface components,
Virtual ecosystems, Browsing in time and space.
Introduction
VIRTUAL ECOSYSTEMS
THE BITS INTERFACE
Traveling in Time
Traveling in Space
Traveling in Time and Space
Object Manipulation
Note Taking
FUTURE WORK
Acknowledgments
