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to simulate the passing of a day, a year, a millennium. Sounds and behaviours can be inte-
grated, so that walking over leaves sounds noticeably different to walking across a lawn,
for example, although this will have implications on the sizes of the source files.
Multimedia links with external material are something with which VRML currently
struggles, though these are bound to be a development of the future.
Viewpoint definitions may be used to give the users a rapid contextual sense of where
they are in the world, and will save time and memory if only a brief overview of the
objects or world is required. In addition to this, virtual fly-through routes may be defined
to highlight aspects of the world to non-active viewers.The usefulness of these will
inevitably depend on the necessity of participation in the world/experience.
One of the most useful current developments in a cultural heritage context is in the
work being done on `avatars' and user profiling. Avatars are virtual representations of
human or computer-generated participants in virtual worlds.Technically, avatars are
cylindrical in VRML, though they may appear to be human-shaped.This cuts down on
the length of multi-user VRML files (cylinders being primitives) but also disallows, for
example, shaking hands or many other human interactions. User profiles can be stored in
a database to allow for repeat visits and the development of relationships both inside and
outside the virtual world. An interesting example of this is the Finnish multi-user world,
Conversations With Angels, which permits multiple online users to interact and chat in real
time using blaxxun's Contact VR browser.
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Development environments
The simplest way of developing a VRML world is by hand-coding it through a basic
text editor such as Microsoft's freely available WordPad, although any text editor would
suffice for this. Hand-coding has the advantage of being highly accurate and efficient, but
the disadvantage of being very complicated and time-consuming.The next step up from
this is a dedicated VRML editor, such as VrmlPad by Parallel Graphics, which assists in
the coding process in the same way as a program like SoftQuad's XMetal facilitates the
creation and editing of XML files with layout guides and debugging features. At the top
of the VRML design chain sits Internet Space Builder by Parallel Graphics, a WYSIWYG
(What You See Is What You Get) interface which, like Dreamweaver, creates less efficient
code and is relatively inexpensive at around
80 per licence, significantly less than it has
cost previously. A similar package is Cosmo Worlds which generates code that is often dif-
ficult to modify by hand.There are a number of applications created to optimise such
auto-created VRML code, including TriVista's VRML DataTrimmer, Radialsoft's VRML
Opt, vwaif (freeware, open-source), Shrinker (freeware, open-source), and Trapezium
Software's
Chisel. Trapezium also produces Vorlon, which checks that code meets VRML
specifications and standards.
Essentially, as with many other heritage technologies, a trade-off will be required
between the cost and the usability of the development environment. Given the ease of
use and speed to learn, a visual environment will usually be preferable to hand coding,
but this comes at a price both fiscal and computational.
Virtual Reality and
Display Technologies
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Research into automatically populating virtual worlds with thousands of avatars is currently being carried
out at University College London. Details can be found at
http://www.cs.ucl.ac.uk/research/vr/Projects/Crowds/index.html. Conversations With Angels
is hosted at http://angels.kiasma.fng.fi/