17-03-2014, 09:39 PM
Abstract
Virtual avatar interactive technology is the
foundation for cooperative multi-user to apperceive
current colony’s working status. When running VRML
program, an invisible explorer avatar can be assumed
in three-dimensional space. Based on VRML,
described its avatar application, extension technology,
browser function and explore navigation. Mainly
studied the NavigationInfo node’s grammatical pattern
and its avatarSize field. These determine the collision
detection and user perspective scope with the
undulating terrain.
Key Words
3D Avatar, Java, Script, Interaction, Browser
1. Introduction
In shared virtual technology, users interact with
surrounding environment by adopting avatar
Interactive Technology. The foundation of this kind of
interaction is the sensing ability of virtual avatar to its
environment, including existence sensing, position
sensing, avatar identification, action sensing and
identity sensing. If be able to sense the environment
variation, then virtual avatar can manipulate objects in
the scene, interact with other user’s avatar, or
formulate action plan according to environment
variation [1].
2. VRML and Avatar
VRML is a kind of modeling language for
constructing virtual environment. It’s a 3D interchange
format, mainly used to describe three dimensional
object and action. Some usually used elements for 3D
application system have been defined, such as
hierarchy transition, light source, viewpoint,
geometrical shape, animation, fog, material
characteristic and texture mapping [2]. The basic target
of VRML is to establish three dimensional and
interactive scenes on Internet. Its foundation
characteristics includes distribution, three dimension,
interaction, multimedia integration and scene
verisimilitude.
In a cooperative multi-user environment, we can
represent a user with a 3D avatar, in the name of this
user, in VRML’s virtual scene. By programming
PROTO sentence, VRML can define multi client
object. Users can choose system provided avatar
object, or alternatively employ object defined by him
selves. In this way, multi-user will be able to
apperceive current colony’s cooperative working
status. In order to realize the effect of what you see is
what I see (WYSIWIS), we should bring all users’
feeedback information into correspondence. A 3D
avatar is a special object in VRML scene. It is the
concrete expression of user’s figure and behavior in
virtual environment [3].
By employing VRML’s ProximitySensor node,
system can trace local user viewpoint’s shift and whirl
status, simultaneously obtaining the Position_changed
and Orientation_changed value. Then this two fields’
value can be used to change 3D avatar’s position and
orientation for other users, who are in the same virtual
scene. Avatars can exchange information among
themselves, through text or animation mode. By the
control of Script node’s TimeSensor sensor, further
control OrientationInterpolator and
PositionInterpolator interpolator, we can dynamically
change avatar object’s orientation to realize avatar
animation. In this way, other users will be able to
apperceive this user’s shifting and whirling to which
object, in which region, and what is the content who is
paying close attention to. When a user goes into or gets
out from the scene, its 3D avatar should be increased or
decreased from virtual cooperative scene.