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2. Our approach, "Shareable
Visits" and VRTalk (top)
The starting point is to observe how the people
interact each other, while visiting together a museum.
All sorts of different situations may arise, but let
us focus, for simplicity, upon three of them:
- Visitor X goes alone at the Museum. He/she can browse across the
different rooms, focus upon the exhibits of his/her interest, resume the wandering. While
he/she is doing this, he/she can look at the other people, see what they are focusing
upon, overhear their conversation, listening to the lecture for a group of tourists in a
guided tour, etc.
- Visitors X, Y, Z … go to the museum together. They talk each
other, exchanging comments, opinions, suggestions. Again they can partially share the
experience of (some of) the other people being in the museum at the same time. Sometimes X
takes the lead, conducts the group, and guides the conversation, etc., with the other
members following him/her, listening to him/her and also exchanging opinions among
themselves. At other times Y (or Z..) takes the leading. The group, anyway, is a loose
one: its members can always go by themselves, or they can stop somewhere, or form
subgroups, …. At moments, however, the members of the original group rejoin together
and proceed in the visit.
- There is an organized tour: a group leader goes across the museum,
pointing at the exhibits of special interest; stopping whenever is needed, providing
comments and explanations. Most of the times the members of the group closely follow the
guide and listen to him/her. Sometimes, however, they "whisper" comments each
other, or they stop somewhere, in order to look to something of their interest, or they
wander freely around, and then go back to join the group. After a while, however, the
memebers join again the group and continue following the guide.
A countless number of variations and combination of
the above-mentioned paradigms, i.e. ways of visiting a museum can be devised. We focus,
for simplicity, upon them calling them, respectively, "free-visit",
"loose-group" and "guided-group".
In the rest of this section we will examine,
briefly, what type of functionality we would need in order to support those types of
visits, while in the next section we will examine our specific technical approach, and a
prototype application being developed in cooperation with the Museum of Science and
Technology of Milan.
Our goal is to allow the user experiencing a
"virtual visit" to share, at some degree, the visit with other users. Our
starting point has been an analysis of the three paradigms above described, end trying to
implement them in a virtual visit.
Assuming the subjective point of view of a virtual
visitor, the following elements of a virtual visit have been analyzed:
- SEEING
Whom other visitors may I see.
- SEEN
Who can see me.
- SCENE
I could look at the scene from fixed points of view,
or from my eyes, from the eyes of someone else (e.g. my friend or my group leader), …
- MOVEMENT
My movement within the virtual scene can be free,
can follows predefined paths, can be dependent upon the movement of somebody else (e.g. my
friend or my group leader), ….
- TALK
I can talk to everybody else
("broadcast"), I can talk to a single person ("whisper"), I can talk
to a small group of people ("chat"), …
- LISTENING
I can listen to everybody, I can listen to a single
person, I can listen to a small group, ..
- TRANSMISSION
The messages can remain the same everywhere within a
virtual world, the messages can degrade with distance, the messages can be confined within
a world, or span over to neighboring worlds, ….
- INTERACTION
The objects within the virtual world can be
"duplicated" (each one gets his/her copy), shared without possibility of
manipulating them, shared with possibility for everybody of manipulating them, shared
within a group but duplicated across groups, …
Several other elements could have been considered,
of course, but the above list seemed long enough to us for an initial experiment.
The question then naturally arises: what type of
technology should be used for the virtual visit?
Without getting into technical details, for the time
being not interesting, we rapidly came to the following conclusion: 2D techniques (the
standard Web techniques) are very good at providing information (images, text, graphic),
and very bed for grasping the overall aspect of a complex situation, with a complex
arrangement of objects, and several people sharing the situation. 3D techniques (either
photographic or graphic) are very good for grasping complex environments, with several
people, and quite bad at communicating information (images, text, video, etc.) of
acceptable quality.
Since our goal was to experiment with cooperation,
while performing virtual visits, we have chosen 3D virtual environment as the fastest way
to get an experimental prototype. Therefore in our current approach 3D is used to browse
the museum and to find the way around, while standard WWW techniques are used to provide
more substantial information.
VRTalk is our experimental environment; it is a
powerful tool that allows creating Virtual Reality three-dimensional worlds, in which
people can meet, by means of an Internet connection. Each one of the virtual visitors can
remotely explore the Virtual world. In addition a virtual visitor can examine and interact
with components of the world. Like in a real world situation, a visitor can see where the
other visitors are currently located, where they are going, and what they are doing.
Visitors exchange opinions or information, with other visitors, through the keyboard.
Visitors can interact with 3D objects, sharing the experience of the interaction, with
other visitors.
At the moment the virtual world must be a VRML world
(a 3D-Java version is planned for summer 99).
With respect to standard VRML worlds a few extra
lines in the code are needed in order to declare which objects are "shareable"
with other users. Our experience is that any "reasonable" VRML world can be
shared, at a substantial degree. The little modifications required today, need an
experienced VRML programmer; by the summer 99 a tool is envisioned in order to automate
the transformation.
In terms of delivery, any user connected via
Internet, that can execute a VRML application (i.e. that has the proper VRML plug-ins
installed) can access a VRTalk application.
In terms of performances, we have experienced
excellent results using Intranets based on LAN’s. Using standard Internet connections
degrades performances, of course; in some cases this degradation can be very disturbing,
spoiling the user satisfaction. In other cases, however, low performances can be even
helpful, since in a cooperative visit everybody should move and react slowly, in order to
get everybody else understanding what he/she is doing or attempting to do. This point will
be exemplified in the next section.
Explaining how VRTalk works, without going into
technical details, it must be said that the shared application runs on a server. All the
clients, i.e. the machines of the actual users, have a local copy of the shared
application. When a client machine (i.e. a visitor) "acts" upon the world, it
"sends" a notification of they action to the server; the server collects all the
notifications of actions, and sends them back to all the clients. Each client, in turn,
when gets notified of an action performed by someone else, updates its local copy of the
shared application. The mechanism above described explains why there can be a certain
delay between the action performed by Visitor X, and the awareness of the action by
Visitor Y. Therefore the application is conceived for "well behaving" visitors;
in other world VRTalk supports a cooperative application (where everybody tries to help
everybody else), and not a competitive application, where someone tries to compete with
someone else for resources.
The user of a VRTalk application sees a browser
window, which is split in two parts. The upper half shows the 3D representation on the
world, in which the visitor can move and interact with objects. In this part the user can
also see other visitors moving and performing actions. A human-shaped figurine, named
avatar, represents every visitor. In the lower half a chat window is provided, in which
visitors can write messages to other visitors, and can read incoming messages.
Textual, audio and video information can be linked
directly within the three-dimensional world, or by popping up contextual 2D web pages
along the VRTalk browser window.
In terms of shaping the cooperation pattern, at
discussed in the previous section, at the moment we are experimenting with very simplified
features, while a more sophisticated environment is envisioned by the summer 99. At the
moment visitors can either belong to the "global environment" or can cluster
themselves into Groups. The cooperation rules are the following:
- A visitor sees the world as populated with the avatars of
the other visitors (placed according to the position of each visitor).
- A visitor can see through "his eyes" (subjective camera)
or through a set of standard cameras; in the latter case he/she can’t see
his/her own avatar.
- A visitor is aware of whoever is in the world (through an
explicit list of names).
- The chat is global in the sense that everybody can speak and
everybody gets what is being said.
- Each visitor can play the role of group leader, but only one
visitor can play the role at any given time point.
- A visitor
sees the world as populated with the avatars of the
other visitors (placed according to the position of each visitor), of his/her own group
only.
A visitor can see through "his eyes" (subjective camera) or
to a set of standard cameras; in the latter case he/she can’t see his/her own avatar.
A visitor can also see through the eyes of the group leader,
i.e. can see at what he/she is looking at.
In the normal situation the visitor can move around independently
from the group leader, and it is up to visitor to try to "follows" the leader.
If, however, the visitor sees through the eyes of the group leader,
he/she is physically tied to the group leader itself, following all its movements.
When the visitor drops off the connection with the group leader, he/she will find
himself/herself in the physical position of the group leader.
A visitor is aware of whoever is in the world (through an explicit
list of names), but only within the limits of the group.
The chat is global only within the limits of the group.
In the next section we briefly illustrate, mainly
through pictures, a prototype application, which is a virtual tour within a portion of the
MST (Museum of Science and Technology) of Milan. It is clear that it is impossible to
reproduce on paper the actual "feeling" of a cooperative virtual visits, but
only a few hints are provided.
3. The Shareable Visit to the Virtual Museum of
Science and Technology of Milan (top)
The prototype application allows a virtual visit
across a few rooms of the MST. The MST hosts several objects, artifacts, pictures and
documents concerning the development of science and technology around the world, but with
a specific emphasis upon Italy. The museum is hosted in an old building, which was used
once as a monastery; one of the nicest spot, in fact, is a cloister. Among the objects
hosted by the museum, specific relevance have the "Leonardo machines": they are
wood machines (build in the period across the end of the last century and the beginning of
this century), trying to physically recreate what is understandable from the drawings of
Leonardo da Vinci. Most of the machines do actually work, in the sense that the visitor of
the "real" museum may operate them.
In our virtual visit we have reproduced the cloister
and a few rooms; we have "slightly" modified the actual floor plan, since the
true one was a little "boring" for a virtual visit. The rooms are
"populated" with a few interactive virtual machines, in the sense that that the
virtual visitor may interact with them. A few billboards are used to access standard Web
pages providing explanatory text.
Therefore, overall, our virtual reproduction is
quite crude or poor. Our goal, at the moment, is mainly to gain experience with
cooperative visits; by summer ’99 a more refined representation of the museum is
planned.
In the experiment, used to generate the pictures,
there were four virtual visitors.
Figure 1 shows
the point of view of one of the visitors: he/she sees 2 avatars representing two other
people currently visiting the cloister.
Figure 2 shows the cloister with three other
visitors and a chat (lower half of the page) going on among them.
Figure 3 shows a room with one of the machines (a
giant screw) that is possible to interact with. The visitor is actually looking at a group
leader.
Figure 4 shows the same situation depicted in
picture 3, with the visitor looking through the eyes of its leader, i.e. looking at what
the leader was actually looking.
4. Conclusions and future work
(top)
The authors of this paper have the firm belief that
transforming virtual visits, from an (essentially) lonely experience, into an experience
that can be shared with other people is a very interesting goal. Applications can range
from commercial ones (cooperative shopping) to cultural ones. Sharing with friends a
virtual visit to a museum, for example, or being lectured by an expert while virtually
visiting a museum, can greatly enhance the pleasure and the cultural outcome of the
experience.
Several problems still make the goal not easily attainable, and we
discuss below a few of them:
- visiting a museum while interacting with other people
Interacting with other people, while virtually visiting can be helpful,
or can be disturbing; the same medium (a very small screen) is used for both activities
and the overall "bandwidth", i.e. the visual communication capacity, is quite
small. In addition current virtual museums assume that the full screen is available to
them; subtracting part of the small screen for other purposes can spoil the whole
experience. So, should we design virtual visits (either 2D or 3d) with specific features,
in order to make them suitable for cooperative visits? On the other hand it is appealing
to allow any virtual visit, as currently designed and implemented, to become shareable
with other visitors
- cooperative visits metaphors
As we have briefly discussed in the previous sections, there are
several ways to organize the group of visitors who can cooperate, several ways to organize
what each visitor can see or can listen to, several ways to coordinate the movements
around, etc.
Our opinion is that we must consider real-life interactions among
visitors as a starting point for requirements, in order to build the initial prototypes.
With these prototypes we can learn about what virtual visitors like to use or do not like
to use or would desire to have. Later, on the basis of the previous experiences and user
reactions, we can develop better metaphors and paradigms.
As we have said in previous sections, we are convinced that 3D graphic
is very god at conveying the physical appearance of a building and the presence (or
absence) of objects and people in it. 3D technology, however, at the moment and for a
while, does not have the capability of communicating high quality content.
2D technology, on the contrary, can easily deliver high quality images,
text and graphics; it does not easily allow, however, to recreate the feeling of being
somewhere, and, even less, of being with someone else.
One possible development is to find a better way to combine 3D
graphics, with standard ways of organizing web-sites. We need better logical organization,
and smoother ways to perform the transition from one representation to the other one.
Another possibility is to improve the quality of the 3D representation,
bringing it at the same level as the standard 2D; this possibility, however, is tied to
the development of technology (both HW and SW), rather than to the to ability of the
application developers.
Performances are an issue for cooperating virtual visits; it takes a
while, over Internet, in order to notify every virtual visitors of what the other visitors
are doing. This inherent slowness can create three types of problems:
- Annoyance of the visitor, for the slowness of the response.
- Application confusion and difficulty of coordinating the interaction.
Think, for example, of visitors X and Y, both wishing to move an object
a little bit on the right.
X does it, and after a while Y (who has not received, yet, the
notification of the action of X) does the same; the result is that the object gets moved
twice as much as it was desired. If now both visitors want to remove the anomaly and move
the object a little on the left, the same wrong procedure can be repeated.
The slowness of the incoming messages and the sudden bursts of messages
coming from several clients at the same time may confuse the server.
On the ground of the above considerations, the following is our
research agenda for the near future:
- to better understand the nature of a cooperative virtual visit, and to improve (also
completing) the prototype application for the MST, in order to meet those requirements.
- To define a wide range of ways of cooperating for virtual visitors and to implement
them.
- To better coordinate the relationship between the 3D environment and a standard,
well-structured, WWW site, also improving the transition from one representation to the
other one.
- To develop a better communication among visitors, in order to improve their interaction,
and also trying to avoid chaotic cooperation.
The above agenda should be completed by the summer ’99. Even
before that time (around the spring 99) we will start, in cooperation with the Museum of
Science and Technology, collecting data about the user satisfaction and about usability of
the application. The data collected from usability testing and the user reactions, will be
the ground to devise better ways to let the "visitors" to cooperate, while
performing their virtual visits.
5. References
(top)
Book:
Rohel B., Couch J., Reed-Ballereich C., Rohaly T., Brown G. (1997). Late
Night VRML 2.0 with Java. Emeryville (CA): Ziff-Davis Press.
Journal Articles:
Garzotto F., Paolini P., Schwabe D. (1993). HDM - A Model Based
Approach to Hypertext Application Design in ACM Trans. on Information Systems,
Vol. 11, No. 1, Jan.
Proceedings:
Garzotto F., Mainetti L., Paolini P. (Oct. 1996). Navigation Patterns in
Museum Hypermedia in Proc. ICHIM'95 - International Conference on Hypermedia for
Museums, S. Diego (CA).
Garzotto F., Mainetti L., Paolini P. (Oct. 1996 ). Navigation Patterns
in Museum Hypermedia in Proc. ICHIM'95 - International Conference on Hypermedia for
Museums, S. Diego (CA).
Garzotto F., Matera M., Paolini P. (April 1998). To Use or Not to Use?
Evaluating Usability of Museum Web Sites Proc. of M&W'98 - International
Conference on Museums and Web, Toronto, Canada.
Electronic Materials with No Printed Analogue:
Reunion des Muséés Nationaux (1994). Le Louvre. CD ROM.
Mountparnasse Multimédie.
Reunion des Muséés Nationaux (1996). Musées d'Orsay. CD ROM.
Mountparnasse Multimédie.
Art Gallery (1993) The Collection of the National Art Gallery, London.
Microsoft.
Web sites:
Lombard University Consortium Internet Access: http://www.lucia.it/
National Gallery of Art:
http://www.nga.gov/
Silicon Graphics - References to Cosmo Software Products
http://vrml.sgi.com
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