Three-dimensional, virtual reality space display processing apparatus, a three dimensional virtual reality space display processing method, and an information providing medium

The sight line of an avatar can be set to a direction independent of a direction in which the avatar moves in a virtual reality space. Buttons 219 and 220 are provided for setting the sight line of the avatar to the direction independent of the direction in which the avatar moves in the virtual reality space. According to the operations of these buttons, the processing for changing sight line directions is performed. For example, the novel constitution allows the avatar to walk on the ground while looking up, thereby preventing unnatural display or unnatural avatar movement in which, when the avatar walks looking up, the avatar moves in the direction of its sight line to be eventually raised away from the ground.

BACKGROUND OF THE INVENTION 
The present invention generally relates to a three-dimensional virtual 
reality space display processing apparatus, a three-dimensional virtual 
reality space display processing method, and an information providing 
medium and, more particularly, to a three-dimensional virtual reality 
space display processing apparatus, a three-dimensional virtual reality 
space display processing method, and an information providing medium that 
allow setting of a direction of the sight line of an avatar regardless of 
moving direction thereof. 
A cyberspace service named Habitat.TM. is known in the so-called personal 
computer communications services such as NIFTY-Serve.TM. of Japan and 
CompuServe.TM. of U.S. in which a plurality of users connect their 
personal computers via modems and public telephone network to the host 
computers installed at the centers of the services to access them in 
predetermined protocols. Development of Habitat started in 1985 by Lucas 
Film of the U.S., operated by Quantum Link, one of U.S. commercial 
networks, for about three years. Then, Habitat started its service in 
NIFTY-Serve as Fujitsu Habitat.TM. in February 1990. In Habitat, users can 
send their alter egos called avatars (the incarnation of a god figuring in 
the Hindu mythology) into a virtual city called Populopolis drawn by 
two-dimensional graphics to have a chat (namely, a realtime conversation 
based on text entered and displayed) with each other. For further details 
of Habitat, refer to the Japanese translation of "Cyberspace: First 
Steps," Michael Benedikt, ed., 1991, MIT Press Cambridge, Mass., 
ISBN0-262-02327-X, the translation being published Mar. 20, 1994, by NTT 
Publishing, ISBN4-87188-265-9C0010, pp. 282-307. 
In such a virtual reality space, a user can move his or her avatar in any 
direction to enjoy a variety of virtual experiences. 
The avatar's moving direction can be specified in one of forward, backward, 
left, and right for example. In some systems, the sight line of an avatar 
can be changed upward or downward for example. 
If a sight line direction 302 of an avatar 301 is directed upward for 
example as shown in FIG. 33, the user can surely see an image in the upper 
direction in a virtual reality space 300. However, if the avatar 301 is 
moved forward with its sight line fixed in that direction (normally, when 
an avatar is moved forward relative to its viewpoint, it moves into the 
depth of the screen; for convenience of description, the left side of the 
screen is assumed to be avatar's forward moving direction), the avatar 301 
moves in the sight line direction 302, raising itself gradually from a 
ground level (horizontal plane) 304 in a tilt manner because the avatar 
301 is designed to move in the sight line direction 302. Consequently, the 
display of the virtual reality space viewed from the viewpoint of the 
avatar 301 becomes an unnatural display not actually seen in a real space 
in which people move around with their feet supported by the ground. 
SUMMARY OF THE INVENTION 
It is therefore an object of the present invention to make the display of a 
virtual reality space viewed from the viewpoint of an avatar look more 
natural with reference to the ground level (horizontal plane) in the real 
space. 
In carrying out the invention and according to claim 1 thereof, there is 
provided a three-dimensional virtual reality space display processing 
apparatus for decoding three-dimensional graphics data to display an image 
of a three-dimensional virtual reality space, comprising: a viewpoint 
position moving means for moving a viewpoint of a user in the 
three-dimensional virtual reality space along a reference plane of the 
three-dimensional virtual reality space and to a direction specified by 
the user; and a sight line direction changing means for changing a 
direction of the sight line of the user in the three-dimensional virtual 
reality space along a virtual plane orthogonally intersecting the 
reference place of the three-dimensional virtual reality space and to a 
direction specified by the user. 
In carrying out the invention and according to claim 5 thereof, there is 
provided a three-dimensional virtual reality space display processing 
method for decoding three-dimensional graphics data to display an image of 
a three-dimensional virtual reality space, comprising the steps of: moving 
a viewpoint of a user in the three-dimensional virtual reality space along 
a reference plane of the three-dimensional virtual reality space and to a 
direction specified by the user; and changing a direction of the sight 
line of the user in the three-dimensional virtual reality space along a 
virtual plane orthogonally intersecting the reference place of the 
three-dimensional virtual reality space and to a direction specified by 
the user. 
In carrying out the invention and according to claim 6 thereof, there is 
provided an information providing medium for providing a computer program 
that is executed by a three-dimensional virtual reality space display 
processing apparatus for displaying an image of a three-dimensional 
virtual reality space, the computer program comprising the steps of: 
moving a viewpoint of a user in the three-dimensional virtual reality 
space along a reference plane of the three-dimensional virtual reality 
space and to a direction specified by the user; and changing a direction 
of the sight line of the user in the three-dimensional virtual reality 
space along a virtual plane orthogonally intersecting the reference place 
of the three-dimensional virtual reality space and to a direction 
specified by the user. 
In the three-dimensional virtual reality space display processing apparatus 
described in claim 1, the three-dimensional virtual reality space display 
processing method described in claim 5, and the information providing 
medium described in claim 6, the sight line direction of an avatar can be 
changed upward or downward and, at the same time, the viewpoint position 
of the avatar can be moved along a reference plane independent of the 
sight line direction in a three-dimensional virtual reality space. It 
should be noted that the information providing medium herein denotes not 
only package media such as a floppy disk and a CD-ROM in which computer 
programs are stored but also a transmission medium by which a computer 
program is downloaded via a network such as the Internet for example.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
This invention will be described in further detail by way of example with 
reference to the accompanying drawings. In order to clarify the 
relationship between the means of the invention described in the claims 
and the following preferred embodiments, each of the means is followed by 
the corresponding preferred embodiment (this embodiment is an example) in 
parentheses. It should be understood that this description is not limited 
to the description of each of the means. 
A three-dimensional virtual reality space display processing apparatus for 
decoding three-dimensional graphics data to display an image of a 
three-dimensional virtual reality space, comprising: a viewpoint position 
moving means (for example, steps S55 through S61 and steps S65 through S72 
of FIG. 28) for moving a viewpoint of a user in the three-dimensional 
virtual reality space along a reference plane of the three-dimensional 
virtual reality space and to a direction specified by the user; and a 
sight line direction changing means (for example, steps S51, S52, S62, and 
S63 of FIG. 28) for changing a direction of the sight line of the user in 
the three-dimensional virtual reality space along a virtual plane 
orthogonally intersecting the reference place of the three-dimensional 
virtual reality space and to a direction specified by the user. 
The three-dimensional virtual reality space display processing apparatus 
described in claim 4 further comprising sight line direction resetting 
means (for example, steps S53 and S64 of FIG. 28) for resetting the sight 
line direction of the user in the three-dimensional virtual reality space 
to a default direction along the reference plane of the three-dimensional 
virtual reality space as specified by the user. 
A three-dimensional virtual reality space display processing method for 
decoding three-dimensional graphics data to display an image of a 
three-dimensional virtual reality space, comprising the steps of: moving a 
viewpoint of a user in the three-dimensional virtual reality space along a 
reference plane of the three-dimensional virtual reality space and to a 
direction specified by the user (for example, steps S55 through S61 and 
S65 through S72 of FIG. 28); and changing a direction of the sight line of 
the user in the three-dimensional virtual reality space along a virtual 
plane orthogonally intersecting the reference place of the 
three-dimensional virtual reality space and to a direction specified by 
the user (for example, steps S51, S52, S62, and S63 of FIG. 28). 
An information providing medium for providing a computer program that is 
executed by a three-dimensional virtual reality space display processing 
apparatus for displaying an image of a three-dimensional virtual reality 
space, the computer program comprising the steps of: moving a viewpoint of 
a user in the three-dimensional virtual reality space along a reference 
plane of the three-dimensional virtual reality space and to a direction 
specified by the user (for example, steps S55 through S61 and S65 through 
S72 of FIG. 28); and changing a direction of the sight line of the user in 
the three-dimensional virtual reality space along a virtual plane 
orthogonally intersecting the reference place of the three-dimensional 
virtual reality space and to a direction specified by the user (steps S51, 
S52, S62, and S63 of FIG. 28). 
It should be noted that an object representing an avatar, or an alter ego 
of a user, can be moved in the virtual reality space, entered in it, and 
made exit from it; in other words, the avatar is changed in its states or 
the states are updated. So, such an object is appropriately called an 
update object hereinafter. On the other hand, an object representative of 
a building constituting a town in the virtual reality space is used 
commonly by a plurality of users and does not change in its basic state. 
Even if the building object changes, it changes autonomously, namely it 
changes independent of the operations made at client terminals. Such an 
object commonly used by a plurality of users is appropriately called a 
basic object hereinafter. 
The basic idea and concept of a virtual society is described by Hiroaki 
Kitano, Sony Computer Science Laboratories, as follows in his home page 
"Kitano Virtual Society (V1.0) 
(http://www.csl,sony.co.jp/person/kitano/VS/concept.j.html.1995)": 
"In the beginning of the 21st century, a virtual society would emerge in a 
network spanning all the world. People in every part of the world will 
make a society in which millions or hundred millions of people live in a 
shared space created in the network. A society that will emerge beyond the 
current Internet, CATV, and the so-called information super highway is a 
virtual society that I conceive. In the virtual society, people can not 
only perform generally the same social activities as those in the real 
world--enjoy shopping, have a chat, play games, do work, and the like--but 
also perform things that are possible only in the virtual society (for 
example, moving from Tokyo to Paris in an instant). Such a "society" would 
be implemented only by state-of-the-art technologies such as cyberspace 
constructing technologies that support a broadband network, high-quality 
three-dimensional presentation capability and bidirectional communications 
of voice, music and moving picture signals, and a large-scale distributed 
system that allows a lot of people to share the constructed space." 
For further details, look at the above mentioned home page. 
The three-dimensional virtual reality space that implements the 
above-mentioned virtual society is a cyberspace system. The actual 
examples of the infrastructures for constructing this cyberspace system 
includes, at this point of time, the Internet, which is a world-wide 
computer network connected by a communications protocol called TCP/IP 
(Transmission Control Protocol/Internet Protocol) and the intranet 
implemented by applying the Internet technologies such as WWW (World Wide 
Web) to the in-house LAN (Local Area Network). Further, use of a broadband 
communication network based on FTTH (Fiber To The Home) in the future is 
proposed in which the main line system and the subscriber system are all 
constituted by fiber optics. 
Meanwhile, for an information providing system available on the Internet, 
WWW developed by CERN (European Center for Nuclear Research) in 
Switzerland is known. This technology allows a user to browse information 
including text, image and voice for example in the hyper text form. Based 
on HTTP (Hyper Text Transfer Protocol), the information stored in a WWW 
server terminal is sent asynchronously to terminals such as personal 
computers. 
The WWW server is constituted by server software called an HTTP demon and 
an HTML file in which hyper text information is stored. The hyper text 
information is described in a description language called HTML (Hyper Text 
Makeup Language). In the description of a hyper text by HTML, a logical 
structure of a document is expressed in a format specification called a 
tag enclosed by "&lt;" and "&gt;". Description of linking to other information 
is made based in link information called an anchor. A method in which a 
location at which required information is stored by the anchor is URL 
(Uniform Resource Locator). 
A protocol for transferring a file described in HTML on the TCP/IP network 
is HTTP. This protocol has a capability of transferring a request for 
information from a client to the WWW server and the requested hyper text 
information stored in the HTML file to the client. 
Used by many as an environment for using WWW is client software such as 
Netscape Navigator.TM. called a WWW browser. 
It should be noted that demon denotes a program for executing control and 
processing in the background when performing a job in the UNIX 
environment. 
Recently, a language for describing three-dimensional graphics data, called 
VRML (Virtual Reality Modeling Language) and a VRML viewer for drawing a 
virtual reality space described in this VRML on a personal computer or a 
workstation have been developed. VRML allows to extend WWW, set hyper text 
links to objects drawn by three-dimensional graphics, and follow these 
links to sequentially access WWW server terminals. The specifications of 
VRML version 1.0 were made public in May 26, 1995. Then, in Nov. 9, 1995, 
a revised version in which errors and ambiguous expressions are corrected 
was made public. The specifications are available from 
URL=http://www.vrml.org/Specifications/VRML1.0/. 
Storing three-dimensional information described in the above-mentioned VRML 
in a WWW server terminal allows the construction of a virtual space 
expressed in three-dimensional graphics on the Internet. Further, use of 
the VRML viewer by using personal computers and the like interconnected by 
the Internet can implement the display of a virtual space based on 
three-dimensional graphics and the walk-through capability. 
In what follows, examples in which the Internet is used for a network will 
be described. It will be apparent to those skilled in the art that FTTH 
may be used instead of the Internet to implement the virtual space. 
It should be noted that Cyberspace is a coinage by William Gibson, a U.S. 
science fiction writer, and was used in his "Neuromancer" (1984) that made 
him famous. Strictly speaking, however, the word Cyberspace first appeared 
in his "Burning Chrome" (1982). In these novels, there are scenes in which 
the hero attaches a special electrode on his forehead to connect himself 
to a computer to directly reflect on his brain a virtual three-dimensional 
space obtained by visually reconfiguring data on a computer network 
spanning all over the world. This virtual three-dimensional space was 
called Cyberspace. Recently, the term has come to be used as denoting a 
system in which a virtual three-dimensional space is used by a plurality 
of users via a network. 
Now, referring to FIG. 1, there is shown an example of a constitution of a 
cyberspace (a three-dimensional virtual reality space provided via a 
network) system according to the present invention. As shown, in this 
preferred embodiment, host computers (or simply hosts) A through C, a 
plurality (three in this case) of client terminals 13-1 through 13-3, and 
any number (one in this case) of service provider terminal 14 are 
interconnected via a world-wide network 15 (a global communication network 
sometimes referred to as an information transmission medium herein) like 
the Internet 15 by way of example. 
The host A constitutes a system of so-called WWW (World Wide Web) for 
example. Namely, the host A has information (or a file) to be described 
later. And, each piece of information (or each file) is related with a URL 
(Uniform Resource Locator) for uniformly specify that information. 
Specifying a URL allows access to the information corresponding to it. 
To be more specific, the host A stores three-dimensional image data for 
providing three-dimensional virtual reality spaces (hereinafter 
appropriately referred to simply as virtual reality spaces) such as 
virtual streets in Tokyo, New York, and other locations for example. It 
should be noted that these three-dimensional image data do not change in 
their basic state; that is, these data include static data consisting of 
only basic objects such as a building and a road to be shared by a 
plurality of users. If the basic state changes, it only reflects an 
autonomous change in the state of a merry-go-round or a neon. The static 
data are considered to be data that are not subject to update. The host A 
has an information server terminal 10 (a basic server terminal). The 
information server terminal 10 is adapted, when it receives a URL via the 
network 15, to provide the information corresponding to the received URL, 
namely a corresponding virtual reality space (in this case, a space 
consisting of only basic objects). 
It should be noted that, in FIG. 1, there is only one host, namely the host 
A, which has an information server terminal for providing the virtual 
reality space (consisting of only basic objects) of a specific area. It is 
apparent that such a host may be installed in plural. 
The host B has a shared server terminal 11. The shared server terminal 11 
controls update objects that constitute a virtual reality space when put 
in it. The update objects are avatars for example representing users of 
the client terminals. Thus, the shared server terminal 11 allows a 
plurality of users to share the same virtual reality space. It should be 
noted, however, that the host B controls only the update objects located 
in a virtual reality space for only a specific area (for example, Tokyo) 
of the virtual reality spaces controlled by the host A. That is, the host 
B is dedicated to the virtual reality space of a specific area. Also, it 
should be noted that the network 15 is connected with, in addition to the 
host B, a host, not shown, having a shared server terminal for controlling 
update objects located in virtual reality spaces of other areas such as 
New York and London, stored in the host A. 
The host C, like the host A, constitutes a WWW system for example and 
stores data including IP (Internet Protocol) addresses for addressing 
hosts (shared server terminals) that control update objects like the host 
B. Therefore, the shared server terminal addresses stored in the host C 
are uniformly related with URLs as with the case of the host A as 
mentioned above. In addition, the host C has a mapping server terminal 12 
(a control server terminal). Receiving a URL via the network 15, the 
mapping server terminal 12 provides the IP address of the shared server 
terminal corresponding to the received URL via the network 15. It should 
be noted that FIG. 1 shows only one host, namely the host C, which has the 
mapping server terminal 12 for providing shared server terminal addresses. 
It will be apparent that the host C can be installed in plural. 
The client terminal 13 (13-1, 13-2 or 13-3) receives a virtual reality 
space from the information server terminal 10 via the network 15 to share 
the received virtual reality space with other client terminals (including 
the service provider terminal 14), under the control of the shared server 
terminal 11. Further, the client terminal 13 is also adapted to receive 
specific services (information) using the virtual reality space from the 
service provider terminal 14. 
The service provider terminal 14, like the client terminal 13, receives a 
virtual reality space to share the same with the client terminal 13 (if 
there is another service provider terminal, it also shares this space). 
Therefore, as far as the capability of this portion is concerned, the 
service provider terminal 14 is the same as the client terminal 13. 
Further, the service provider terminal 14 is adapted to provide specific 
services to the client terminal 13. It should be noted that FIG. 1 shows 
only one service provider terminal 14. It will be apparent that the 
service provider terminal may be installed in plural. 
The following briefly describes a WWW system constituted by the host A and 
the host C. Referring to FIG. 2, WWW is one of the systems for providing 
information from hosts X, Y, and Z to unspecified users (client terminals) 
via the network 15 (the Internet in the case of WWW). The information that 
can be provided in this system include not only texts but also graphics, 
images (including still images and moving pictures), voices, 
three-dimensional images, and hyper texts which combines all these 
information. 
In WWW, a URL, or a form for uniformly represent these pieces of 
information is determined. Specifying a specific URL, each user can obtain 
the information corresponding to the specified URL. As shown in FIG. 3, 
each URL is composed of a protocol type for representing a service type 
(http in the preferred embodiment of FIG. 3, which is equivalent to a 
command for retrieving a file corresponding to a file name to be described 
later and send the retrieved file), a host name indicating a destination 
of the URL (in the embodiment of FIG. 3, www.csl.sony.co. jp), and a file 
name of data to be sent (in the embodiment of FIG. 3, index.html) for 
example. 
Each user operates the client terminal to enter a URL for desired 
information. When the URL is entered, the client terminal references a 
host name, for example, contained in the URL. A link with a host (in the 
embodiment of FIG. 2, the host X for example connected to the Internet) 
addressed by the host name is established. Then, at the client terminal, 
the URL is sent to the linked host, namely the host X, via the Internet, 
requesting the host X for sending the information specified in the URL. In 
the host X, an HTTP demon (httpd) is operating on the information server 
terminal (the WWW server terminal). Receiving the URL, the information 
server terminal sends back the information specified in the URL to the 
client terminal via the Internet. 
The client terminal receives the information from the information server 
terminal to display the received information on its monitor as required. 
Thus, the user can get the desired information. 
Therefore, only storing in the host such data for describing elements 
(objects) for constituting a virtual reality space as shapes of basic 
objects (for example, a rectangular prism and a cone) and locations and 
attributes (color and texture for example) of these basic objects allows 
to provide the virtual reality space (consisting of only basic objects in 
this case) to unspecified users. Namely, as long as the Internet is used 
for the network 15 and WWW is used, virtual reality spaces can be provided 
to unspecified users world-wide with ease and at a low cost because the 
Internet itself already spans almost all over the world and the 
description of the elements constituting each virtual reality space to be 
stored in hosts does not require to make changes to information servers 
(WWW server terminals) constituting WWW. It should be noted that the 
service for providing the description of the elements constituting a 
virtual reality space is upward compatible with existing services provided 
by WWW. 
Storing in a specific host (a mapping server terminal) the IP addresses of 
other hosts as information also allows to provide the host IP addresses to 
unspecified users world-wide with ease. 
It should be noted that it is difficult for a plurality of users to share 
the same virtual reality space if only the description (the data of 
three-dimensional image for providing the virtual reality space of a 
specific area) of elements constituting the virtual reality space is 
stored in a host constituting WWW. Namely, in WWW, the information 
corresponding to a URL is only provided to a user and therefore no control 
for information transfer is performed. Hence, it is difficult to transfer 
between users the above-mentioned change information of update objects by 
using WWW without changing its design. Therefore, in the cyberspace system 
of FIG. 1, the host B having the shared server terminal 11 and the host C 
having the mapping server 12 are installed to allow a plurality of users 
to share the same virtual reality space, details of which will be 
described later. 
Next, FIG. 4 shows an example of the constitution of the information server 
terminal 10 that operates on the host A of FIG. 1. As shown in FIG. 4, the 
information server terminal 10 has a CPU 81 which performs a variety of 
processing operations according to a program stored in a ROM 82. In the 
information server 10, the above-mentioned HTTP demon is operating in the 
background. A RAM 83 stores data and program necessary for the CPU 81 to 
perform the variety of processing operations. A communication device 84 is 
adapted to transfer specific data with the network 15. A storage device 85 
composed of a hard disc, an optical disc, and magneto-optical disc stores 
the data of the three-dimensional images for providing a virtual reality 
space of a specific area such as Tokyo or New York for example along with 
URLs as mentioned above. 
FIG. 5 shows an example of the constitution of the shared server terminal 
11 operating on the host B of FIG. 1. As shown, the shared server terminal 
has a CPU 21 which executes a variety of processing operations according 
to a program stored in a ROM 22. A RAM 23 appropriately stores data and a 
program necessary for the CPU 21 to execute the variety of processing 
operations. A communication device 24 transfers specific data with the 
network 15. 
A display device 25 has a CRT (Cathode Ray Tube) or an LCD (Liquid Crystal 
Display) for example and is connected to interface 28 to monitor images of 
the virtual reality space (composed of not only basic objects but also 
update objects) of an area controlled by the shared server terminal 11. 
The interface 28 is also connected with a microphone 26 and a loudspeaker 
27 to supply a specific voice signal to the client terminal 13 and the 
service provider terminal 14 and monitor a voice signal coming from these 
terminals. 
The shared server terminal 11 has an input device 29 on which a variety of 
input operations are performed via the interface 28. This input device has 
at least a keyboard 29a and a mouse 29b. 
A storage device 30 composed of a hard disc, an optical disc, and a 
magneto-optical disc stores data of the virtual reality space of an area 
controlled by the shared server terminal 11. It should be noted that the 
data of the virtual reality space are the same as those stored in the 
storage device 85 of the information server terminal 10 (of FIG. 4). When 
these data are displayed on the display device 25, the virtual reality 
space of the area controlled by the shared server terminal 11 is 
displayed. 
FIG. 6 shows an example of the constitution of the mapping server terminal 
12 operating on the host C of FIG. 1. Components CPU 91 through 
communication device 94 are generally the same in constitution as those of 
FIG. 4, so that the description of the components of FIG. 6 is omitted in 
general. A storage device 95 stores addresses, along with URLs, for 
identifying shared server terminals that control update objects (in the 
embodiment of FIG. 1, only the shared server terminal 11 is shown; 
actually, other shared server terminals, not shown, are connected to the 
network 15). 
FIG. 7 shows an example of the constitution of the client terminal 13 
(actually, client terminals 13-1 through 13-3). The client terminal 13 has 
a CPU 41 which executes a variety of processing operations according to a 
program stored in a ROM 42. A RAM 43 appropriately stores data and a 
program necessary for the CPU 41 to executes the variety of processing 
operations. A communication device 44 transfers data via the network 15. 
A display device 45 has a CRT or an LCD to display three-dimensional images 
created by computer graphics or taken by an ordinary video camera. A 
microphone 46 is used to output a voice signal to the shared server 
terminal 11. A loudspeaker 47 outputs the voice signal coming from the 
shared server terminal 11. An input device 49 is operated to perform a 
variety of input operations. 
A keyboard 49a of the input device 49 is operated when entering text 
(including an URL) composed of specific characters and symbols. A mouse 
49b is operated when entering specific positional information. A viewpoint 
input device 49c and a movement input device 49d are operated when 
changing the state of the avatar as an update object of the client 
terminal 13. That is, the viewpoint input device 49c is used to enter the 
viewpoint of the avatar of the client terminal 13, thereby moving the 
viewpoint of the avatar vertically, horizontally or in the depth 
direction. The movement input device is used to move the avatar in the 
forward and backward direction or the right and left direction at a 
specific velocity. It is apparent that the operations done through the 
viewpoint and movement input devices may also be done through the 
above-mentioned keyboard 49a and the mouse 49b. 
A storage device 50 composed of a hard disc, an optical disc, and 
magneto-optical disc stores avatars (update objects) representing users. 
Further, the storage device 50 stores a URL (hereinafter appropriately 
referred to as an address acquisition URL) for acquiring an IP address of 
a shared server terminal for managing update objects to be located in the 
virtual reality space of each area stored in the information server 
terminal 10 (if there is an information server terminal other than the 
information server terminal 10, that information server terminal is 
included). The address acquisition URL is stored as associated with a URL 
(hereinafter appropriately referred to as a virtual reality space URL) 
corresponding to the data of the virtual reality space of that area. This 
setup allows to obtain the address acquisition URL for acquiring the IP 
address of the shared server terminal for controlling the virtual reality 
space of that area when the virtual reality space URL for the data of the 
virtual reality space for that area has been entered. 
Interface 48 constitutes the data interface with a display device 45, a 
microphone 46, a loudspeaker 47, an input device 49, and the storage 
device 50. 
FIG. 8 shows an example of the constitution of the service provider 
terminal 14 of FIG. 1. The components including a CPU 51 through a storage 
device 60 are generally the same as the components including the CPU 41 
through the storage device 50 and therefore the description of the CPU 51 
through the storage device 60 is omitted. 
FIG. 9 shows schematically a virtual reality space that is provided by the 
information server terminal 10 of FIG. 1 and can be shared by a plurality 
of users under the control of the shared server terminal 11. As shown in 
FIG. 9, this virtual reality space constitutes a town, in which avatar C 
(avatar of the client terminal 13-1 for example) and avatar D (avatar of 
the client terminal 13-2 for example) can move around. 
Avatar C sees an image as shown in FIG. 10 for example from the position 
and viewpoint in the virtual reality space. Namely, data associated with 
the basic objects constituting the virtual reality space are provided to 
the client terminal 13-1 from the information server terminal 10 to be 
stored in a RAM 43 (or a storage device 50). Then, from the RAM 43 (or the 
storage device 50), data are read out of a virtual reality space that can 
be seen when the same is seen from specific viewpoint and position and the 
read data are supplied to the display device 45. Then, when the viewpoint 
and position of avatar C are changed by operating a viewpoint input device 
49c and a movement input device 49d, data corresponding the change are 
read from the RAM 43 (or the storage device 50) to be supplied to the 
display device 45, thereby changing the virtual reality space (the 
three-dimensional image) being displayed on the display device 45. 
Further, data associated with another user's avatar (an update object) 
(avatar D of FIG. 10) that can be seen when the virtual reality space is 
seen from the current viewpoint and position are supplied to the client 
terminal 13-1 from the shared server terminal 11. Based on the supplied 
data, the display on the display device 45 is changed. Namely, in the 
state of FIG. 9, since avatar C is looking in the direction of avatar D, 
avatar D is displayed in the image (the virtual reality space) displayed 
on the display device 45 of the client terminal 13-1 as shown in FIG. 10. 
Likewise, an image as shown in FIG. 11 is displayed on the display device 
45 of the client terminal 13-2 to which avatar D corresponds. This 
displayed image is also changed by moving the viewpoint and position of 
avatar D. It should be noted that, in FIG. 9, avatar D is looking in the 
direction of avatar C, so that avatar C is displayed in the image (the 
virtual reality space) on the display device 45 of the client terminal 
13-2 as shown in FIG. 11. 
The service provider terminal 14 controls a part of the sharable virtual 
reality space provided by the information server terminal 10 and the 
shared server terminal 11. In other words, the service provider purchases 
a part of the virtual reality space from administrators (information 
providers who provide information of the virtual reality space) of the 
information server terminal 10 and the shared terminal 11. This purchase 
is performed in the real space. Namely, upon request by a specific service 
provider for the purchase of the virtual reality space, the administrators 
of the information server terminal 10 and the shared server terminal 11 
allocate a part of the requested virtual reality space to that specific 
service provider. 
For example, assume that the owner (service provider) of the service 
provider terminal 14 lease a room in a specific building in the virtual 
reality space and use the room as a shop for electric appliances. The 
service provider provides information about commodities, for example 
televisions, to be sold in the shop. Based on the information, the server 
terminal administrator creates three-dimensional images of the televisions 
by computer graphics and place the created images at specific positions in 
the shop. Thus, the images to be placed in the virtual reality space have 
been completed. 
Similar operations are performed by other service providers to form the 
virtual reality space as a big town for example. 
FIG. 12 is a top view of a virtual reality space (a room in a building in 
this example) to be occupied by the service provider owning the service 
provider terminal 14. In this embodiment, one room of the building is 
allocated to this service provider in which two televisions 72 and 73 are 
arranged with a service counter 71 placed at a position shown. The service 
provider of the service provider terminal 14 places his own avatar F 
behind the service counter 71. It will be apparent that the service 
provider can move avatar F to any desired position by operating a movement 
input device 59d of the service provider terminal 14. 
Now, assume that avatar C of the client terminal 13-1 has come in this 
electric appliances shop as shown in FIG. 12. At this moment, an image as 
shown in FIG. 13 for example is displayed on the display device 45 of the 
client terminal 13-1, in correspondence to the position and viewpoint of 
avatar C. If avatar F is located behind the service counter 71, an image 
as shown in FIG. 14 is displayed on a display device 55 of the service 
provider terminal 14. As shown in FIGS. 13 and 14, the image viewed from 
avatar C shows avatar F, while the image viewed from avatar F shows avatar 
C. 
As shown in FIG. 13, the image viewed from avatar C shows a cursor 74 to be 
used when a specific image is specified from the client terminal 13-1. 
Likewise, as shown in FIG. 14, a cursor 75 is shown for the service 
provider terminal 14 to specify a specific image. 
Moving avatar C around the television 72 or 73 by operating the movement 
input device 49d of the client terminal 13-1 displays on the display 
device 45 the image corresponding to avatar C's moved position and 
viewpoint. This allows the user to take a close look at the televisions as 
if they were exhibited in a shop of the real world. 
Also, when the user moves the cursor 74 by operating a mouse 49b and then 
click on avatar F, a conversation request signal is transmitted to the 
service provider terminal 14 corresponding to avatar F. Receiving the 
conversation request signal, the service provider terminal 14 can output, 
via a microphone 56, a voice signal to a loudspeaker 47 of the client 
terminal 13-1 corresponding to avatar C. Likewise, entering a specific 
voice signal from a microphone 46 of the client terminal 13-1 can transmit 
user's voice signal to a speaker 57 of the service provider terminal 14. 
Thus, the user and service provider can make conversation in a usual 
manner. 
It is apparent that the conversation can be requested from avatar F (the 
service provider terminal 14) to avatar C (the client terminal 13-1). 
When the cursor 74 is moved on the client terminal 13-1 and the image of 
the television 72 for example is clicked, the information (the provided 
information) describing the television 72 is provided in more detail. This 
can be implemented by linking the data of the virtual reality space 
provided by the information server terminal 10 with the description 
information about the television. It is apparent that the image for 
displaying the description information may be either three-dimensional or 
two-dimensional. 
The specification of desired images can be performed also from the service 
provider terminal 14. This capability allows the service provider to offer 
the description information to the user in a more active manner. 
If the service provider specifies avatar C with the cursor 75 by operating 
the mouse 59b, the image corresponding to the position and viewpoint of 
avatar C, namely, the same image as displayed on the display device 45 of 
the client terminal 13-1 can be displayed on the display device 55 of the 
service provider terminal 14. This allows the service provider to know 
where the user (namely avatar C) is looking at and therefore promptly 
offer information needed by the user. 
The user gets explanations about the products, or gets the provided 
information or description information. If the user wants to buy the 
television 72 for example, he can buy the same actually. In this case, the 
user requests the service provider terminal 14 for the purchase via avatar 
F. At the same time, the user transmits his credit card number for example 
to the service provider terminal 14 (avatar F) via avatar C. Then, the 
user asks the service provider terminal for drawing an amount equivalent 
to the price of the television purchased. The service provider of the 
service provider terminal 14 performs processing for the drawing based on 
the credit card number and make preparations for the delivery of the 
purchased product. 
The images provided in the above-mentioned virtual reality space are 
basically precision images created by computer graphics. Therefore, 
looking at these images from every angle allows the user to make 
observation of products almost equivalent to the observation in the real 
world, thereby providing surer confirmation of products. 
Thus, the virtual reality space contains a lot of shops, movie houses and 
theaters for example. Because products can be actually purchased in the 
shops, spaces installed at favorable locations create actual economic 
values. Therefore, such favorable spaces themselves can be actually 
(namely, in the real world) purchased or leased. This provides complete 
distinction from the so-called television shopping system ordinarily 
practiced. 
The following describes the operations of the client terminal 13 (or the 
service provider terminal 14), the information server terminal 10, the 
mapping server terminal 12, and the shared server terminal 11 with 
reference to the flowcharts of FIGS. 15 through 18. 
Now, referring to FIG. 15, there is shown an example of processing by the 
client terminal 13 (or the service provider terminal 14). In step S1, the 
CPU 41 checks whether a virtual reality space URL has been entered or not. 
If no virtual reality space URL has been found, the processing remains in 
step S1. If a virtual reality space URL has been found in step S1, namely, 
if a virtual reality space URL corresponding to a desired virtual reality 
space entered by the user by operating the keyboard 49a has been received 
by the CPU 41 via interface 48, the process goes to step S2. In step S2, a 
WWW system is constituted as described with reference to FIG. 2 and the 
virtual reality space URL is transmitted from the communication device 44 
via the network 15 to the information server terminal of a specific host 
(in this case, the information server terminal 10 of the host A for 
example) that has the information server terminal, thereby establishing a 
link. 
Further, in step S2, an address acquisition URL related to the virtual 
reality space URL is read from the storage device 50 to be transmitted 
from the communication device 44 via the network 15 to the mapping server 
terminal of a specific host (in this case, mapping server terminal 12 of 
the host C for example) that constitutes the WWW system, thereby 
establishing Then, the process goes to step S3. In step S3, data 
(three-dimensional image data) of the virtual reality space or the IP 
address of the shared server terminal 12 corresponding to the virtual 
reality space URL received in step S2 or the address acquisition URL is 
received by the communication device 44. 
Namely, in step S2, the virtual reality space URL is transmitted to the 
information server terminal 10. When this virtual reality space URL is 
received by the information server terminal 10, the data of the 
corresponding virtual reality space are transmitted to the client terminal 
13 via the network 15 in step S22 of FIG. 16 to be described. Thus, in 
step S3, the data of the virtual reality space transmitted from the 
information server terminal 10 are received. It should be noted that the 
received virtual reality space data are transferred to the RAM 43 to be 
stored there (or first stored in the storage device 50 to be transferred 
to the RAM 43. 
Also, in step S2, the address acquisition URL is transmitted to the mapping 
server terminal 12. When the address acquisition URL is received by the 
mapping server terminal 12, the IP address of the shared server terminal 
corresponding to the URL is transmitted to the client terminal 13 via the 
network 15 in step S32 of FIG. 17 to be described. Thus, in step S3, the 
IP address of the shared server terminal 12 transmitted from the mapping 
server 12 is received. 
As described above, the address acquisition URL related to the entered 
virtual reality space URL corresponds to the IP address of the shared 
server terminal that controls the update object placed in the virtual 
reality space corresponding to that virtual reality space URL. Therefore, 
for example, if the entered virtual reality space URL corresponds to a 
virtual reality space of Tokyo and the shared server terminal 11 owned by 
the host B controls the update objects placed in the Tokyo virtual reality 
space, the IP address of the shared server terminal 11 is received in step 
S3. Consequently, the user can automatically get the location (the IP 
address) of the shared server terminal that controls the virtual reality 
space of a desired area even if the user does not know which shared server 
terminal controls the update objects in a virtual reality space in which 
area. 
It should be noted that, in steps S2 and S3, the processing of transmitting 
the virtual reality space URL and the address acquisition URL and 
receiving the virtual reality space data and the IP address is actually 
performed by transmitting the virtual reality space URL, receiving the 
data of the corresponding virtual reality space, transmitting the address 
acquisition URL, and then receiving the corresponding IP address in this 
order by way of example. 
When the virtual reality space data and the shared server terminal IP 
address are received in step S3, the process goes to step S4. In step S4, 
a connection request is transmitted from the communication device 44 via 
the network 15 to the shared server terminal (in this case, the shared 
server terminal 11 for example) corresponding to the IP address (the 
shared server terminal IP address) received in step S3. This establishes a 
link between the client terminal 13 and the shared server terminal 11. 
Further, in step S3, after the establishment of the link, the avatar 
(namely, the update object) representing oneself stored in the storage 
device 50 is transmitted from the communication device 44 to the shared 
server terminal 11. 
When the shared server terminal 11 receives the user's avatar, the same to 
then transmitted to the client terminals of other users existing in the 
same virtual reality space (in this case, that of Tokyo as mentioned 
above). Then, on the client terminals of other users, the transmitted 
avatar is placed in the virtual reality space, thus implementing the 
sharing of the same virtual reality space among a plurality of users. 
It should be noted that, rather than providing the user's avatar from the 
client terminal 13 to the shared server terminal 11, a predetermined 
avatar may also be allocated from the shared server terminal 11 to each 
user who accessed the same. Also, in the client terminal 13, the avatar of 
the user himself who uses this terminal can be placed and displayed in the 
virtual reality space however, the user cannot see himself in the real 
world, so that it is desirable for the user's avatar not be displayed on 
that user's client terminal in order to make the virtual reality space as 
real as possible. 
When the processing of step S4 has been completed, the process goes to step 
S5. In step S5, the data of the virtual reality space that can be seen 
when the same is seen from specific viewpoint and position are read from 
the RAM 43 by the CPU 41 to be supplied to the display device 45. Thus, 
the specific virtual reality space is shown on the display device 45. 
Then, in step S6, the communication device 44 determines whether update 
information of another user's avatar has been sent from the shared server 
terminal 11. 
As described above, the user can update the position or viewpoint of his 
own avatar by operating the viewpoint input device 49c or the movement 
input device 49d. If the update of the position or viewpoint of the avatar 
is instructed by using this capability, the CPU 41 receives the 
instruction via the interface 48. According to the instruction, the CPU 41 
performs processing for outputting positional data or viewpoint data 
corresponding to the updated position or viewpoint as update information 
to the shared server terminal 11. In other words, the CPU 41 controls the 
communication device 44 to transmit the update information to the shared 
server terminal 11. 
Receiving the update information from the client terminal, the shared 
server terminal 11 outputs the update information to other client 
terminals in step S44 of FIG. 18 to be described. It should be noted the 
shared server terminal 11 is adapted to transmit the avatar received from 
the client terminal that requested for access to client terminals of other 
users, this avatar being transmitted also as update information. 
When the update information has come as mentioned above, it is determined 
in step S6 that update information of the avatar of another user has come 
from the shared server terminal 11. In this case, this update information 
is received by the communication device 44 to be outputted to the CPU 41. 
The CPU 41 updates the display on the display device 45 according to the 
update information in step S7. That is, if the CPU 41 receives the 
positional data or viewpoint data from another client terminal as update 
information, the CPU 41 moves or changes (for example, the orientation of 
the avatar) the avatar of that user according to the received positional 
data or viewpoint data. In addition, if the CPU 41 receives the avatar 
from another client terminal, the CPU 41 places the received avatar in the 
currently displayed virtual reality space at a specific position. It 
should be noted that, when the shared server terminal 11 transmits an 
avatar as update information, the shared server terminal also transmits 
the positional data and viewpoint data of the avatar along with the update 
information. The avatar is displayed on the display device 45 according to 
these positional data and viewpoint data. 
When the above-mentioned processing has come to an end, the process goes to 
step S8. 
Meanwhile, if, in step S6, no update information of the avatar of another 
user has come from the shared server terminal 11, the process goes to step 
S8, skipping step S7. In step S8, the CPU 41 determines whether the 
position or viewpoint of the avatar of the user of the client terminal 13 
has been updated or not by operating the viewpoint input device 49c or the 
movement input device 49d. 
In step S8, if the CPU 41 determines that the avatar position or viewpoint 
has been updated, namely, if the viewpoint input device 49c or the 
movement input device 49d has been operated by the user, the process goes 
to step S9. In step S9, the CPU 41 reads data of the virtual reality space 
corresponding to the position and viewpoint of the avatar of the user 
based on the entered positional data and viewpoint data, makes 
calculations for correction as required, and generates the image data 
corresponding to the correct position and viewpoint. Then, the CPU 41 
outputs the generated image data to the display device 45. Thus, the image 
(virtual reality space) corresponding to the viewpoint and position 
entered from the viewpoint input device 49c and the movement input device 
49d is displayed on the display device 45. 
Further, in step S10, the CPU 41 controls the communication device 44 to 
transmit the viewpoint data or the positional data entered from the 
viewpoint input device 49c or the movement input device 49d to the shared 
server terminal 11, upon which process goes to step 11. 
Here, as described above, the update information coming from the client 
terminal 13 is received by the shared server terminal 11 to be outputted 
to other client terminals. Thus, the avatar of the user of the client 
terminal 13 is displayed on the other client terminals. 
On the other hand, in step S8, if CPU 41 determines that the avatar's 
position or viewpoint has not been updated, the process goes to step S11 
by skipping steps S9 and S10. In step S11, the CPU 41 determines whether 
the end of the update data input operation has been instructed by 
operating a predetermined key on the keyboard; if the end has not been 
instructed, the process goes back to step S6 to repeat the processing. 
Referring to the flowchart of FIG. 16, there is shown an example of the 
processing by the information server terminal 10. First, the communication 
device 84 determines in step S21, whether a virtual reality space URL has 
come from the client terminal 13 via the network 15. If, in step S21, the 
communication device 84 determines that no virtual reality space URL has 
come, the process goes back to step S21. If the virtual reality space URL 
has come, the same is received by the communication device 84, upon which 
the process goes to step S22. In step S22, the data of the virtual reality 
space related to the virtual reality space URL received by the 
communication device 84 are read by the CPU 81 to be transmitted via the 
network 15 to the client terminal 13 that transmitted the virtual reality 
space URL. Then, the process goes back to step S21 to repeat the 
above-mentioned processing. 
FIG. 17 shows an example of the processing by the mapping server terminal 
12. In the mapping server terminal 12, the communication device 94 
determines in step S 31, whether an address acquisition URL has come from 
the client terminal 13 via the network 15. If no address acquisition URL 
has come, the process goes back to step S31. If the address acquisition 
URL has come, the same is received by the communication device 94, upon 
which the process goes to step 32. In step S32, the IP address (the IP 
address of the shared server terminal) related to the address acquisition 
URL received by the communication device 94 is read from the storage 
device 95 by the CPU 91 to be transmitted via the network 15 to the client 
terminal 13 that transmitted the address acquisition URL. Then, the 
process goes back to step S31 to repeat the above-mentioned processing. 
FIG. 18 shows an example of the processing by the shared server terminal 
11. In the shared server terminal 11, the communication device 24 
determines, in step S41, whether a connection request has come from the 
client terminal 13 via the network 15. If no connection request has come, 
the process goes to step S43 by skipping step S42. If the connection 
request has come, that is, if the client terminal 13 has the connection 
request to the shared server terminal 11 in step S4 of FIG. 15, the 
communication link with the client terminal 13 is established by the 
communication device 24, upon which the process goes to step S42. 
In step S42, a connection control table stored in the RAM 23 is updated by 
the CPU 21. Namely, it is necessary for the shared server terminal 11 to 
recognize the client terminal 13 with which the shared server terminal 11 
is linked, in order to transmit update information coming from the client 
terminal 13 to other client terminals. To do so, when the communication 
link with client terminals has been established, the shared server 
terminal 11 registers the information for identifying the linked client 
terminals in the connection control table. That is, the connection control 
table provides a list of the client terminals currently linked to the 
shared server terminal 11. The information for identifying the client 
terminals include the source IP address transmitted from each client 
terminal as the header of TCP/IP packet and a nickname of the avatar set 
by the user of each client terminal. 
Then, the process goes to step S43, in which the communication device 24 
determines whether the update information has come from the client 
terminal 13. If, in step S43, no update information has been found, the 
process goes to step S45 by skipping step S44. If the update information 
has been found, namely, if the client terminal 13 has transmitted, in step 
S10 of FIG. 15, positional data and viewpoint data as the update 
information to the shared server terminal 11 (or, in step S4 of FIG. 15, 
the client terminal 13 has transmitted the avatar as the update 
information to the shared server terminal 11 after transmission of the 
connection request), the update information is received by the 
communication device 24, upon which the process goes to step S44. In step 
S44, the CPU 21 references the connection control table stored in the RAM 
23 to transmit the update information received by the communication device 
24 to other client terminals than the client terminal which transmitted 
that update information. At this moment, the source IP address of each 
client terminal controlled by the connection control table is used. 
It should be noted that the above-mentioned update information is received 
by the client terminal 13 in step S6 of FIG. 15 as described above. 
Then, the process goes to step S45, in which the CPU 21 determines whether 
the end of processing has been instructed by the client terminal 13. If 
the end of processing has not been instructed, the process goes back to 
S41 by skipping step S46. If the end of processing has been instructed, 
the process goes to step S46. In step S46, the link with the client 
terminal 13 from which the instruction has come is disconnected by the 
communication device 24. Further, from the connection control table, the 
information associated with the client terminal 13 is deleted by the CPU 
21, upon which the process goes back to step S41. 
Thus, the control of the update objects is performed by the shared server 
terminal 11 and the control (or provision) of the basic objects is 
performed by the information server terminal 10 constituting the WWW of 
the Internet used world-wide, thereby easily providing virtual reality 
spaces that can be shared by unspecified users world-wide. It should be 
noted that the specifications of the existing WWW system need not be 
modified to achieve the above-mentioned objective. 
Provision of the virtual reality space data by use of the WWW system need 
not create any new web browser because the transfer of these data can be 
made using related art web browsers such as the Netscape Navigator.TM. 
offered by Netscape Communications, Inc. for example. 
Moreover, because the IP address of the shared server terminal 11 is 
provided by the mapping server terminal 12, the user can share a virtual 
reality space with other users without knowing the address of the shared 
server terminal. 
In what follows, a procedure of communications between the client terminal 
13, the information server terminal 10, the shared server terminal 11, and 
the mapping server terminal 12 will be described with reference to FIG. 
19. When the user desires to get a virtual reality space, the user enters 
the URL (the virtual reality space URL) corresponding to the virtual 
reality space of the desired area. Then, the entered URL is transmitted 
from the client terminal 13 to the information server terminal 10 (http). 
Receiving the URL from the client terminal 13, the information server 
terminal 10 transmits the data (three-dimensional scene data representing 
only basic objects) of the virtual reality space associated with the URL 
to the client terminal 13. The client terminal 13 receives and display 
these data. 
It should be noted that, at this stage of processing, no link is 
established between the client terminal 13 and the shared server terminal 
11, so that the client terminal 13 does not receive update information; 
therefore, a virtual reality space composed of only basic objects, namely 
a virtual reality space shown only a still street for example, is shown 
(that is, no update objects such as avatars of other users are displayed). 
Further, the address acquisition URL related to the virtual reality space 
URL is transmitted from the client terminal 13 to the mapping server 
terminal 12. The mapping server terminal 12 receives the address 
acquisition URL to transmit the IP address (the IP address of a shared 
server terminal controlling update objects located in the virtual reality 
space of the area related to the virtual reality space URL, for example, 
the shared server terminal 11) related to the received address acquisition 
URL to the client terminal 13. 
Here, it is possible that the IP address related to the address acquisition 
URL transmitted by the client terminal 13 is not registered in the mapping 
server terminal 12. Namely, a shared server terminal for controlling the 
update objects located in the virtual reality space of the area related to 
the virtual reality space URL may not be installed or operating for 
example. In such a case, the IP address of the shared server terminal 
cannot be obtained, so that a virtual reality space composed of only basic 
objects, a virtual reality space showing only a still street for example, 
is displayed. Therefore, in this case, sharing of a virtual reality space 
with other users is not established. Such a virtual reality space can be 
provided only by storing the virtual reality space data (namely, basic 
objects) in an information server terminal (a WWW server terminal) by the 
existing WWW system. This denotes that the cyberspace system according to 
the present invention is upward compatible with the existing www system. 
Receiving the IP address (the IP address of the shared server terminal 11) 
from the mapping server terminal 12, the client terminal 13 transmits a 
connection request to a shared server terminal corresponding to the IP 
address, namely the shared server terminal 11 in this case. Then, when a 
communication link is established between the client terminal 13 and the 
shared server terminal 11, the client terminal 13 transmits the avatar 
(the three-dimensional representation of the user) representing itself to 
the shared server terminal 11. Receiving the avatar from the client 
terminal 13, the shared server terminal 11 transmits the received avatar 
to the other client terminals linked to the shared server terminal 11. At 
the same time, the shared server terminal 11 transmits the update objects 
(shapes of shared three-dimensional objects), the other users' avatars, 
located in the virtual reality space of the area controlled by the shared 
server terminal 11, to the client terminal 13. 
In the other client terminals, the avatar of the user of the client 
terminal 13 is placed in the virtual reality space to appear on the 
monitor screens of the other client terminals. In the client terminal 13, 
the avatars of the other client terminals are placed in the virtual 
reality space to appear on its monitor screen. As a result, all the users 
of the client terminals linked to the shared server terminal 11 share the 
same virtual reality space. 
Then, when the shared server terminal 11 receives the update information 
from other client terminals, transmits the received update information to 
the client terminal 13. Receiving the update information, the client 
terminal 13 changes the display (for example, the position of the avatar 
of another user is changed). When the state of the avatar of the user of 
the client terminal 13 is changed by that user, the update information 
reflecting that change is transmitted from the client terminal 13 to the 
shared server terminal 11. Receiving this update information, the shared 
server terminal 11 transmits the same to the client terminals other than 
the client terminal 13. Thus, on these other client terminals, the state 
of the avatar of the user of the client terminal 13 is changed accordingly 
(namely, the state of the avatar is changed as the same has been changed 
by the user of the client terminal 13 on the same). 
Subsequently, the processing in which the client terminal 13 transmits the 
update information about the avatar of its own and receives the update 
information from the shared server terminal 11 to change the display based 
on the received update information continues until the connection with the 
shared server terminal 11 is disconnected. 
Thus, the sharing of the same virtual reality space is established by 
transferring the update information via the shared server terminal 11 
among the users. Therefore, if the shared server terminal 11 and the 
client terminal 13 are located remotely, there occurs a delay in the 
communication between these terminals, deteriorating the response in the 
communication. To be more specific, if the shared server terminal 11 is 
located in U.S. for example and users in Japan are accessing the same, 
update information of user A in Japan is transmitted to user B in Japan 
via U.S., thereby taking time until a change made by user A is reflected 
in user B. 
To overcome such a problem, rather than installing only one shared server 
terminal in the world, a plurality of shared server terminals are 
installed all over the world. And the IP addresses of the plurality of 
shared server terminals are registered in the mapping server terminal 12 
to make the same provide the IP address of the shared server terminal in 
the geographical proximity to the client terminal 13. 
To be more specific, as shown in FIG. 20, a shared server terminals W1 and 
W2 for controlling the update objects placed in a virtual reality space (a 
three-dimensional space) such as an amusement park are installed in Japan 
and U.S. respectively by way of example. When the users in Japan and U.S. 
have received the data of the amusement park's virtual reality space, each 
user transmits an address acquisition URL related to a virtual reality 
space URL corresponding to the amusement park's virtual reality space to 
the mapping server terminal 12 (the same address acquisition URL is 
transmitted from all users). At this moment, the users in Japan transmit 
the IP address of the shared server terminal WI installed in Japan to the 
mapping server terminal 12, while the users in U.S. transmit the IP 
address of the shared server terminal W2 installed in U.S. to the mapping 
server terminal 12. 
Here, the mapping server terminal 12 identifies the installation locations 
of the client terminals that transmitted the address acquisition URLs to 
the mapping server terminal in the following procedure. 
In the communication in TCP/IP protocol, a source IP address and a 
destination IP address are described in the header of a TCP/IP packet. 
Meanwhile, an IP address is made up of 32 bits and normally expressed in a 
decimal notation delimited by dot in units of eight bits. For example, an 
IP is expressed in 43.0.35.117. This IP address provides an address which 
uniquely identifies a source or destination terminal connected to the 
Internet. Because an IP address expressed in four octets (32 bits) is 
difficult to remember, a domain name is used. The domain name system (DNS) 
is provided to control the relationship between the domain names assigned 
to the terminals all over the world and their IP addresses. The DNS 
answers a domain name for a corresponding IP address and vice versa. The 
DNS functions based on the cooperation of the domain name servers 
installed all over the world. A domain name is expressed in "hanaya@ipd. 
sony.co.jp" for example, which denotes a user name, @, a host name, an 
organization name, an organization attribute, and country name (in the 
case of U.S., the country name is omitted) in this order. If the country 
name of the first layer is "jp", that terminal is located in Japan. If 
there is no country name, that terminal is located in U.S. 
Using a domain name server 130 as shown FIG. 23, the mapping server 
terminal 12 identifies the installation location of the client terminal 
that transmitted the address acquisition URL to the mapping server 
terminal. 
To be more specific, the mapping server terminal asks the domain name 
server 130 controlling the table listing the relationship between the 
source IP addresses of the requesting client terminal and the domain names 
assigned with the IP addresses for the corresponding domain name. Then, 
the mapping server terminal identifies the country in which a specific 
client terminal is installed based on the first layer of the domain name 
of the client terminal obtained from the domain name server 130. 
In this case, since the client terminal used by each user and its shared 
server terminal are located in geographical proximity to each other, the 
above-mentioned problem of a delay, or the deterioration of response time 
is solved. 
In this case, the virtual reality space provided to the users in Japan and 
U.S. is the same amusement park's virtual reality space as mentioned 
above. However, since the shared server terminals that control the sharing 
are located in both countries, the sharing by the users in Japan is made 
independently of the sharing by the users in U.S. Namely, the same virtual 
reality space is shared among the users in Japan and shared among the 
users in U.S. Therefore, in this case, the same virtual reality space is 
provided from the information server terminal 10, but separate shared 
spaces are constructed among the users in both countries, thereby enabling 
the users to make a chat in their respective languages. 
However, it is possible for the users of both countries to share the same 
virtual reality space by making connection between the shared server 
terminals W1 and W2 to transfer update information between them. 
The deterioration of response also occurs when the excess number of users 
access the shared server terminal 11. This problem can be overcome by 
installing a plurality of shared server terminals for controlling the 
update objects placed in the virtual reality space in the same area in 
units of specific areas, for example, countries or prefectures and making 
the mapping server terminal 12 provide the addresses of those shared 
server terminals which are accessed less frequently. 
To be more specific, a plurality of shared server terminals W3, W4, W5, and 
so on are installed and the mapping server terminal 12 is made provide the 
IP address of the specific shared server terminal W3 for example for 
specific URLs. Further, in this case, communication is performed between 
the mapping server terminal 12 and the shared server terminal W3 for 
example to make the shared server terminal W3 transmit the number of 
client terminals accessing the shared server terminal W3 to the mapping 
server terminal 12. Then, when the number of client terminals accessing 
the shared server terminal W3 has exceeded a predetermined level (100 
terminals for example, which do not deteriorate the response of the shared 
server terminal W3) and if the mapping server terminal 12 has received 
another URL, the mapping server terminal 12 provides the IP address of 
another shared server terminal W4 for example (it is desired that the W4 
be located in the proximity to the shared server terminal W3). 
It should be noted that, in this case, the shared server terminal W4 may be 
put in the active state in advance; however, it is also possible to start 
the shared server W4 when the number of client terminals accessing the 
shared server W3 has exceeded a predetermined value. 
Then, communication is performed between the mapping server terminal 12 and 
the shared server terminal W4. When the number of client terminals 
accessing the shared server terminal W4 has exceeded a predetermined 
value, and the mapping server terminal 12 has received another URL, the 
mapping server terminal 12 provides the IP address of the shared server 
terminal W5 (however, if the number of client terminals accessing the 
shared server terminal W3 has dropped below the predetermined level, the 
mapping server terminal 12 provides the IP address of the W3). 
This setup protects each of the shared server terminals W3, W4, W5 and so 
on from application of excess load, thereby preventing the deterioration 
of response. 
It should be noted that the above-mentioned capability can be implemented 
by controlling by the mapping server terminal 12 the IP addresses of 
shared server terminals to be outputted for specific URLs, so that the 
client terminal 13 and the software operating on the same need not be 
modified. 
The present embodiment has been described by taking the user's avatar for 
example as the update object to be controlled by the shared server 
terminal 11; it is also possible to make the shared server terminal 
control any other update objects than avatars. It should be noted, 
however, that the client terminal 13 can also control update objects in 
some cases. For example, an update object such as a clock may be 
controlled by the client terminal 13 based on the built-in clock of the 
same, updating the clock. 
Further, in the present embodiment, the hosts A through C, the client 
terminals 13-1 through 13-3, and the service provider terminal 14 are 
interconnected via the network 15, which is the Internet; however, in 
terms of using the existing WWW system, the host A having the information 
server terminal 10 or the host C having the mapping server terminal 12 may 
only be connected with the client terminal 13 via the Internet. Further, 
if the user recognizes the address of the shared server terminal 11 for 
example, the host A having the information server terminal 10 and the 
client terminal 13 may only be interconnected via the Internet. 
In addition, in the present embodiment, the information server terminal 10 
and the mapping server terminal 12 operate on different hosts; however, if 
the WWW system is used, these server terminals may be installed on the 
same host. It should be noted that, if the WWW system is not used, the 
information server terminal 10, the shared server terminal 11, and the 
mapping server terminal 12 may all be installed on the same host. 
Still further, in the present embodiment, the data of the virtual reality 
spaces for each specific area are stored in the host A (namely, the 
information server terminal 10); however, these data may also be handled 
in units of a department store or an amusement park for example. 
In the above-mentioned preferred embodiments of the invention, the basic 
objects are supplied to each client terminal 13 via the network 15; 
however, it is also possible to store the basic objects in an information 
recording medium such as a CD-ROM and distribute the same to each user in 
advance. In this case, each client terminal 13 is constituted as shown in 
FIG. 21. To be more specific, in the embodiment of FIG. 21, a CD-ROM drive 
100 is connected to the interface 48 to drive a CD-ROM 101 in which a 
virtual reality composed of basic objects is stored. The other part of the 
constitution is the same as that of FIG. 7. 
Thus, provision of the data of basic objects from the CD-ROM 101 eliminates 
the time for transferring the data via the network 15, increasing 
processing speed. 
Alternatively, the data of basic objects supplied from the information 
server terminal 10 may be stored in the storage device 50 only for the 
first time to be subsequently read for use. 
Namely, the basic object data can be stored in the storage device 85 of the 
information server terminal 10 (for the cases 1 through 3), the storage 
device 50 of the client terminal 13 (for the cases 4 through 6) or the 
CD-ROM 101 of the client terminal 13 (for the cases 7 through 9). 
On the other hand, the update object data can be stored in the storage 
device 85 of the information server terminal 10 (for the case 1) or the 
storage device 30 of the shared server terminal 11 (for the cases 2 
through 9). In the case in which the update object data are stored in the 
shared server terminal 11, that shared server terminal may be the shared 
server terminal 11-1 in Japan (for the case 2, 5 or 8) or the shared 
server terminal 11-2 in U.S. (for the case 3, 6 or 9) as shown in FIG. 23 
for example. In this instance, the URL of the update object data is stored 
on the mapping server terminal 12. 
If the update object data are stored on the information server terminal 10, 
the URL of the update object data is the default URL controlled by the 
information server terminal 10 (in the case of 1). Or if the shared server 
terminal 11 is specified by the user manually, the URL of update object 
data is the specified URL (in the case of 4 or 7). 
Referring to FIG. 23, the data in each of the above-mentioned cases in FIG. 
22 flows as follows. In the case 1, the basic object data are read from a 
VRML file (to be described later in detail) stored in an HDD (Hard Disk 
Drive), storage device of a WWW server terminal 121 operating as the 
information server terminal 10 to be supplied to the client terminal 13-1 
for example via the Internet 15A operating as the network 15. The storage 
device of the WWW server terminal 121 also stores update object data. To 
be more specific, when the basic object data are read in the WWW server 
terminal 121, the URL of the corresponding update object data is stored as 
the default URL in the storage device of the WWW server terminal 121 in 
advance. From this default URL, the update object data are read to be 
supplied to the client terminal 13-1. 
In the case 2, the basic object data are supplied from the WWW server 
terminal 121 to the client terminal 13-1 in Japan via the Internet 15A. On 
the other hand, the update object data are supplied from the shared server 
terminal 11-1 in Japan specified by the mapping server terminal 12 to the 
client terminal 13-1 via the Internet 15A. 
In the case 3, the basic object data are supplied from the WWW server 
terminal 121 to the client terminal 13-2 in U.S. via the Internet 15A. The 
update object data are supplied from the shared server terminal 11-2 in 
U.S. specified by the mapping server terminal 12 via the Internet 15A. 
In the case 4, the basic object data are stored in advance in the storage 
device 50 of the client terminal 13-1 in Japan for example. The update 
object data are supplied from the shared server terminal 11-2 in U.S. for 
example specified by the client terminal 13-1. 
In the case 5, the basic object data are stored in advance in the storage 
device 50 of the client terminal 13-1. The update object data are supplied 
from the shared server terminal 11-1 in Japan specified by the mapping 
server terminal 12 via the Internet 15A. 
In the case 6, the basic object data are stored in advance in the storage 
device 50 of the client terminal 13-2 in U.S. The update object data are 
supplied from the shared server terminal 11-2 in U.S. specified by the 
mapping server terminal 12 to the client terminal 13-2 via the Internet 
15A. 
In the case 7, the basic object data stored in the CD-ROM 101 are supplied 
to the client terminal 13-1 in Japan for example via the CD-ROM drive 100. 
The update object data are supplied from the shared server terminal (for 
example, the shared server terminal 11-1 or 11-2) specified by the client 
terminal 13-1. 
In the case 8, the basic object data are supplied from the CD-ROM 101 to 
the client terminal 13-1. The update object data are supplied from the 
shared server terminal 11-1 in Japan specified by the mapping server 
terminal 12 in Japan. 
In the case 9, the basic object data are supplied from the CD-ROM 101 to 
the client terminal 13-2 in U.S. The update object data are supplied from 
the shared server terminal 11-2 in U.S. specified by the mapping server 
terminal 12 via the Internet 15A. 
In what follows, the software for transferring the above-mentioned virtual 
reality space data to display the same on the display device. In the WWW 
system, document data are transferred in a file described in HTML (Hyper 
Text Markup Language). Therefore, text data are registered as an HTML 
file. 
On the other hand, in the WWW system, three-dimensional graphics data are 
transferred for use by describing the same in VRML (Virtual Reality 
Modeling Language) or E-VRML (Enhanced Virtual Reality Modeling Language). 
Therefore, as shown in FIG. 24 for example, a WWW server terminal 112 of 
remote host 111 constituting the above-mentioned information server 
terminal 10, the shared server terminal 11 or the mapping server terminal 
12 stores in its storage device both HTML and E-VRML files. 
In an HTML file, linking between different files is performed by URL. In a 
VRML or E-VRML file, such attributes as WWWAnchor and WWWInline can be 
specified for objects. WWWAnchor is an attribute for linking a hyper text 
to an object, a file of link destination being specified by URL. WWWInline 
is an attribute for describing an external view of a building for example 
in parts of external wall, roof, window, and door for example. An URL can 
be related to each of the parts. Thus, also in VRML or E-VRML files, link 
can be established with other files by means of WWWAnchor or WWWInline. 
For application software (a WWW browser) for notifying a WWW server 
terminal of a URL entered in a client terminal in the WWW system to 
interpret and display an HTML file coming from the WWW server terminal, 
Netscape Navigator (register trade name) (hereafter referred to simply as 
Netscape) of Netscape Communications, Inc. is known. For example, the 
client terminal 13 also uses Netscape to user the capability for 
transferring data with the WWW server terminal. 
It should be noted, however, that this WWW browser can interpret an HTML 
file and display the same; but this WWW browser cannot interpret and 
display a VRML or E-VRML file although it can receive these files. 
Therefore, a VRML browser is required which can interpret a VRML file and 
an E-VRML file and draw and display them as a three-dimensional space. 
Details of VRML are disclosed in the Japanese translation of "VRML: 
Browsing & Building Cyberspace," Mark Pesce, 1995, New Readers Publishing, 
ISBN 1-56205-498-8, the translation being entitled "Getting to Know VRML: 
Building and Browsing Three-Dimensional Cyberspace," translated by Kouichi 
Matsuda, Terunao Gamaike, Shouichi Takeuchi, Yasuaki Honda, Junichi 
Rekimoto, Masayuki Ishikawa, Takeshi Miyashita and Kazuhiro Hara, 
published Mar. 25, 1996, Prenticehall Publishing, ISBN4-931356-37-0. 
The applicant hereof developed Community Place.TM. as application software 
that includes this VRML browser. 
Community Place is composed of the following three software programs: 
(1) Community Place Browser 
This is a VRML browser which is based on VRML 1.0 and prefetches the 
capabilities (motion and sound) of VRML 2.0 to support E-VRML that 
provides moving picture capability. In addition, this provides the 
multi-user capability which can be connected to Community Place Bureau. 
For the script language, TCL/TK is used. 
(2) Community Place Conductor 
This is a VRML authoring system which is based on E-VRML based on VRML 1.0. 
This tool can not only simply construct a three-dimensional world but also 
give a behavior, a sound, and an image to the three-dimensional world with 
ease. 
(3) Community Place Bureau 
This is used for a server terminal system for enabling people to meet each 
other in a virtual reality space constructed on a network, connected from 
the Community Place Browser. 
In the client terminals 13-1 and 13-2 shown in FIG. 23, Community Place 
Bureau Browser is installed in advance and executed. In the shared server 
terminals 11-1 and 11-2, Community Place Bureau is installed in advance 
and executed. FIG. 25 shows an example in which Community Place Bureau 
Browser is installed from the CD-ROM 101 and executed on the client 
terminal 13-1 and, in order to implement the shared server terminal 
capability and the client terminal capability on a single terminal, 
Community Place Bureau and Community Place Bureau Browser are installed 
from the CD-ROM 101 in advance and executed. 
As shown in FIG. 24, Community Place Bureau Browser transfers a variety of 
data with Netscape as a WWW browser based on NCAPI (Netscape Client 
Application Programming Interface).TM.. 
Receiving an HTML file and a VRML file or E-VRML file from the WWW server 
terminal 11-2 via the Internet, Netscape stores the received files in the 
storage device 50. Netscape processes only the HTML file. The VRML or 
E-VRML file is processed by Community Place Bureau Browser. 
E-VRML is an enhancement of VRML 1.0 by providing behavior and multimedia 
(sound and moving picture) and was proposed to the VRML Community, 
September 1995, as the first achievement of the applicant hereof. Then, 
the basic model (event model) for describing motions as used in E-VRML was 
inherited to the Moving Worlds proposal, one the VRML 2.0 proposals. 
In what follows, Community Place Bureau Browser will be outlined. After 
installing this browser, selecting "Manual" from "Community Place Folder" 
of "Program" of the start menu of Windows 95.TM. (or in Windows NT.TM., 
the Program Manager) displays the instruction manual of the browser. 
It should be noted that Community Place Browser, Community Place Conductor, 
Community Place Bureau, and the files necessary for operating these 
software programs are recorded in a recording medium such as the CD-ROM 
101 to be distributed as a sample. 
Operating Environment of the Browser 
The operating environment of the browser is as shown in FIG. 26. The 
minimum operating environment must be at least satisfied. However, 
Netscape Navigator need not be used if the browser is used as a standalone 
VRML browser. In particular, on using in the multi-user, the recommended 
operating environment is desirable. 
Installing the Browser 
The browser can be usually installed in the same way as Netscape is 
installed. To be more specific, vscplb3a.exe placed in the Sony.TM. 
directory of the above-mentioned CD-ROM 101 is used as follows for 
installation. 
(1) Double-click vscplb3a.exe. The installation package is decompressed 
into the directory indicated by "Unzip To Directory" column. The 
destination directory may be changed as required. 
(2) Click "Unzip" button. And the installation package is decompressed. 
(3) "12 files unzipped successfully" appears. Click "OK" button. 
(4) When "Welcome" windows appeared, click "NEXT" button. 
(5) Carefully read "Software License Agreement." If agreed, press "Yes" 
button; if not, press "No" button. 
(6) Check the directory of installation. Default is "Program Files 
SonyCommunity Place." 
(7) If use of the above-mentioned directory is not wanted, press "Browse" 
button and select another directory. Then, press "Next" button. 
(8) To read "readme" file here, click "Yes" button. 
(9) When the installation has been completed, click "OK" button. 
Starting the Browser 
Before starting the browser, setting of Netscape Navigator must be 
performed. If the browser is used standalone, this setting need not be 
performed; just select "Community Place Folder . . . Community Place" of 
"Program" of the start menu and start. The following setting may be 
automatically performed at installation. 
(1) From "Options" menu of Netscape Navigator, execute "General Preference" 
and open "Preference" window. From the upper tab, select "Helper 
Applications." 
(2) Check "File type" column for "x-world/x-vrml". If it is found, go to 
(4) below. 
(3) Click "Create New Type" button. Enter "x-world" in "Mime Type" column 
and "x-vrml" in "Mime SubType" column. Click "OK" button. Enter "wrl" in 
"Extensions" column. 
(4) Click "Launch the Application:" button. Enter the path name of 
Community Place Browser in the text column below this button. Default is 
"Program FilesSonyCommunity Placebinvscp.exe". 
(5) Click "OK" button. 
Thus, the setting of Netscape Navigator has been completed. Start the 
browser as follows: 
(1) In "File..Open File" menu of Netscape, read "readme.htm" of the sample 
CD-ROM 101. 
(2) Clicking the link to the sample world, and Community Place is 
automatically started, loading the sample world from the CD-ROM 101. 
Uninstalling the Browser 
Execute "Uninstall" from "Community Place Folder" of "Program" of the start 
menu (or in Windows NT, the Program Manager), the browser will be 
uninstalled automatically. 
Operating the Browser 
The browser may be operated intuitively with the mouse 49b, the keyboard 
49a, and the buttons on screen. 
Moving Around in the Three-Dimensional Space 
In the three-dimensional space provided by VRML, such movements done in 
real world as forward, backward, rotate right and rotate left for example 
can be done. The browser implements such movements through the following 
interface: 
By Keyboard 
Each of the arrow keys, not shown, on the keyboard 49a generates the 
following corresponding movement: 
.fwdarw. rotate right; 
.rarw. rotate left; 
.uparw. move forward; and 
.dwnarw. move backward. 
By Mouse 
operate the mouse all with its left button. 
(1) Keep the left button of the mouse 49b pressed in the window of 
CyberPassage and move the mouse to the right for rotate right;to the left 
for rotate left;up for forward; and down for backward. The velocity of 
movement depends on the displacement of the mouse. 
(2) With the Ctrl (Control) key, not shown, on the keyboard 49a kept 
pressed, click an object on screen to get to the front of the clicked 
object. 
The Following Precautions are Needed 
If a collision with an object occurs, a collision sound is generated and 
the frame of screen blinks in red. If this happens, any forward movement 
is blocked. Moving directions must be changed. 
If the user is lost or cannot see anything in the space, click "Home" 
button on the right of screen, and the user can return to the home 
position. 
Jumping Eye 
While navigating through a three-dimensional space, the user may be lost at 
occasions. If this happens, the user can jump up to have an overhead view 
around. 
(1) Click "Jump" button on the right of screen, and the user enters the 
jumping eye mode and jump to a position from which the user look down the 
world. 
(2) Click "Jump" button again, and the user goes down to the original 
position. 
(3) Alternatively, click any place in the world, and the user gets down to 
the clicked position. 
Selecting an Object 
When the mouse cursor is moved around on the screen, the shape of the 
cursor is transformed into a grabber (hand) on an object. In this state, 
click the left button of the mouse, and the action of the grabbed object 
can be called. 
Loading a VRML File 
A VRML file can be loaded as follows: 
In Netscape, click the link to the VRML file; 
From "File..Open File" menu of Community Place Bureau, select the file 
having extension "wrl" on disc. 
In "File..Open URL" menu of Community Place Bureau, enter the URL. 
Click the object in the virtual space for which "URL" is displayed on the 
mouse cursor. 
Operating Toolbar Buttons 
Buttons in the toolbar shown in FIG. 30 for example may be used to execute 
frequently used functions. 
"Back" Go back to the world read last. 
"Forward" Go to the world after going back to the previous world. 
"Home" Move to the home position. 
"Undo" Return a moved object to the original position (to be described 
later). 
"Bookmark" Attach a book to the current world or position. 
"Scouter" Enter in the scouter mode (to be described later) 
"Jump" Enter in the jump eye mode. 
Scouter Mode 
Each object placed in a virtual world may have a character string as 
information by using the E-VRML capability. 
(1) Click "Scouter" button on the right of screen, and the user enters the 
scouter mode. 
(2) When the mouse cursor moves onto an object having an information label, 
the information label is displayed. 
(3) Click "Scouter" button again, and the user exits the scouter mode. 
Moving an Object Around 
With "Alt" (Alternate) key, not shown, on the keyboard 49a pressed, press 
the left button of the mouse 49b on a desired object, and the user can 
move that object to a desired position with the mouse. This is like moving 
a coffee cup for example on s desk with the hand in the real world. In the 
virtual reality, however, objects that can be moved are those having 
movable attributes. It should be noted that a moved object may be restored 
to the position before movement only once by using "Undo" button. 
Connecting to a Multi-User Server Terminal 
This browser provides a multi-user capability. The multi-user capability 
allows the sharing of a same VRML virtual space among a plurality of 
users. Currently, the applicant hereof is operating Community Place Bureau 
in the Internet on an experimental basis. By loading a world called 
chatroom the server terminal can be connected to share a same VRML virtual 
space with other users, walking together, turning off a room light, having 
a chat, and doing other activities. 
This capability is started as follows: 
(1) Make sure that the user's personal computer is linked to the Internet. 
(2) Load the Chatroom of the sample world into CyberPassage Browser. This 
is done by loading "Sonyreadme.htm" from the sample CD-ROM 101 clicking 
"Chat Room". 
(3) Appearance of "Connected to VS Server" in the message window indicates 
successful connection. 
Thus, the connection to the server has been completed. Interaction with 
other users is of the following two types: 
Telling Others of an Action 
This is implemented by clicking any of "Hello", "Smile", "Wao!", "Wooo!!", 
"Umm . . .", "Sad", "Bye" and so on in the "Action" window. The actions 
include rotating the user himself (avatar) right or left 36 degrees, 180 
degrees or 360 degrees. 
Talking With Others 
This capability is implemented by opening the "Chat" window in "View. Chat" 
menu and entering a message from the keyboard 49a into the bottom input 
column. 
Multi-User Worlds 
The following three multi-user worlds are provided by the sample CD-ROM 
101. It should be noted that chat can be made throughout these three 
worlds commonly. 
1) Chat Room 
This is a room in which chat is made mainly. Some objects in this room are 
shared among multiple users. There are objects which are made gradually 
transparent every time the left button of the mouse is pressed, used to 
turn off room lights, and hop when clicked, by way of example. Also, there 
are hidden holes and the like. 
(2) Play With a Ball!! 
When a ball in the air is clicked, the ball flies toward the user who 
clicked the ball. This ball is shared by all users sharing that space to 
play catch. 
(3) Share Your Drawing 
A whiteboard is placed in the virtual space. When it is clicked by the left 
button, the shared whiteboard is displayed. Dragging with the left button 
draws a shape on the whiteboard, the result being shared by the users 
sharing the space. 
Use of community Place Bureau allows the users using Community Place 
Browser to enter together a world described in VRML 1.0. To provide a 
three-dimensional virtual reality space for enabling this capability, a 
file described in VRML 1.0 must be prepared. Then, the Bureau (Community 
Place Bureau being hereinafter appropriately referred to simply as the 
Bureau) is operated on an appropriate personal computer. Further, a line 
telling the personal computer on which Bureau is operating is added to the 
VRML 1.0 file. The resultant VRML file is read into Community Place 
Browser (hereinafter appropriately referred to simply as the Browser), the 
Browser is connected to the Bureau. 
If this connection is successful, the users in the virtual world can see 
each other and talk each other. Further, writing an appropriate script 
into the file allows each user to express emotions through a use of action 
panel ("Action" part in a multi-user window 202 of FIG. 29 to be 
described). 
Community Place Browser provides interface for action description through 
use of TCL. This interface allows each user to provide behaviors to 
objects in the virtual world and, if desired, make the resultant objects 
synchronize between the Browsers. This allows a plurality of users to play 
a three-dimensional game if means for it are prepared. 
To enjoy a multi-user virtual world, three steps are required, preparation 
of a VRML file, start of the Bureau, and connection of the Browser. 
Preparing a VRML File 
First, a desired VRML. 1.0 file must be prepared. This file is created by 
oneself or a so-called freeware is used for this file. This file presents 
a multi-user virtual world. 
Starting the Bureau 
The operating environment of Community Place Bureau is as follows: 
CPU . . . 486SX or higher 
OS . . . Window 95 
Memory . . . 12 MB or higher 
This Bureau can be started only by executing the downloaded file. When the 
CyberPassage Bureau is executed, only a menu bar indicating menus is 
displayed as shown in FIG. 27. Just after starting, the Bureau is in 
stopped state. Selecting "status" by pulling down "View" menu displays the 
status window that indicates the current the Bureau state. At the same 
time, a port number waiting for connection is also shown. 
Immediately after starting, the Bureau is set such that it waits for 
connection at TCP port No. 5126. To change this port number, pull down 
"options" menu and select "port". When entry of a new port number is 
prompted, enter a port number 5000 or higher. If the user does not know 
which port number to enter, default value (5126) can be used. 
To start the Bureau from the stopped state, pull down "run" menu and select 
"start". The server terminal comes to be connected at the specified port. 
At this moment, the state shown in "status" window becomes "running". 
Thus, after completion of the bureau preparations, when the Browser comes 
to connect to the Bureau, it tells the position of the Browser to another 
Browser or transfers information such as conversation and behavior. 
The "status" window of the Bureau is updated every time connection is made 
by the user, so that using this window allows the user to make sure of the 
users existing in that virtual world. 
Connection of the Browser 
Connection of the Browser requires the following two steps. First, instruct 
the Browser to which Bureau it is to be connected. This is done by writing 
an "info" node to the VRML file. Second, copy the user's avatar file to an 
appropriate direction so that you can be seen from other users. 
Adding to a VRML File 
When writing a line specifying the Bureau to be connected to the VRML file, 
a name of the personal computer on which the Bureau is operating and the 
port number must be specified in the following format: 
DEF VsServer Into {string"server name:port number"} 
The server terminal name is a machine name as used in the Internet on which 
the Bureau is operating (for example, fred.research.sony.com) or its IP 
address (for example, 123.231.12.1). The port number is one set in the 
Bureau. 
Consequently, the above-mentioned format becomes as follows for example:DEF 
VsServer Info {string "fred. research.sony.com:5126"} 
In the example of FIG. 25, the IP address of the shared server terminal 
11-1 is 43.0.35.117, so that the above-mentioned format becomes as 
follows:DEF VsServer Info {string"43.0.35.117:5126"} 
This is added below the line shown below of the prepared VRML file: 
#VRML V1.0 ascii 
Copying an Avatar File 
When Community Place Browser gets connected to Community Place Bureau, the 
former notifies the latter of its avatar. When a specific avatar meets 
another, the Bureau notifies the other Browsers of the meeting information 
to make the specific avatar be displayed on the other Browsers. For this 
reason, it is required to copy the VRML file of the specific avatar to an 
appropriate place in advance. 
FIG. 27 shows a display example of a display device 45 of the client 
terminal 13 on which the avatar of the user is arranged in a circus park 
which is a three-dimensional virtual reality space. The image displayed 
therein is an image as viewed from the own avatar in the circus park. 
Currently, the avatar is looking at a child clown in the forward 
direction. 
This display screen also shows a variety of buttons 211 through 221 for 
moving (or navigating) the avatar in the three dimensional virtual reality 
space. It should be noted that moving the own avatar is equivalent to 
moving the viewpoint position of the user along the reference plane (the 
ground or horizontal plane) in the three-dimensional virtual reality 
space. 
The arrow button 211 is operated to move the avatar forward. The arrow 
button 212 is operated to move the avatar backward. The arrow buttons 213 
and 214 are operated to rotate the avatar to the left and to the right 
respectively. 
The triangle buttons 215 through 218 are operated to move the avatar 
upward, downward, to the left, and to the right respectively. 
The upper pedal button 219 is operated to move the sight line of the avatar 
upward. The lower pedal button 220 is operated to move the sight line of 
the avatar downward. The arc arrow button 221 is operated to reset the 
sight line direction such that the sight line of the avatar is moved to 
the horizontal reference plane (the preset default direction horizontal to 
the ground). 
In order to execute the processing corresponding to the operations of these 
navigation buttons, the client terminal 13 executes the processing shown 
in FIG. 28. Namely, in steps S51 through S61, it is determined whether the 
buttons 211 through 218 have been operated respectively. 
In step S51, if the button 219 has been found operated, then, in step S62, 
the processing for moving the sight line of the avatar upward is executed. 
This displays an image obtained by viewing upward from that point on the 
display device 45 of the client terminal 13. If the button 219 is kept 
operated, the angle of the sight line direction from the horizontal 
direction grows gradually and, when the button 219 is released, the sight 
line is fixed there. 
In step S52, if the button 220 has been found operated, the processing for 
moving down the sight line of the avatar is executed. Namely, in this 
case, an image obtained by viewing down from that point is displayed. Like 
the operation of the button 219, if the button 220 is kept operated, the 
angle of the direction of the current sight line from the horizontal 
direction to downward grows gradually and, when the button 220 is 
released, the sight line is fixed there. 
Further, in step S53, if the button 221 has been found operated, then, in 
step S64, the processing for setting the sight line to a preset 
predetermined reference direction (in this embodiment, the horizontal 
direction). Namely, in the state in which the sight line is directed in an 
upward direction or a downward direction from a predetermined angle by 
operating the button 219 or 220, the sight line can be returned if 
required to the horizontal direction by operating the button 220 or 219. 
However, this operation takes time. In such a case, operating the button 
221 immediately sets the sight line to the horizontal direction. 
FIG. 29 shows changes in the sight line direction corresponding to the 
operations of the buttons 219 through 221. As shown in the figure, 
operating the button 219 changes the sight line of an avatar 401 upward 
and operating the button 220 changes the sight line of the avatar 401 
downward. This changes the direction of the sight line in a range of 
.+-.90 degrees from the horizontal direction. When the button 221 is 
operated, the direction of the sight line is immediately reset to the 
horizontal direction along a reference plane 404 in the three-dimensional 
virtual reality space no matter which direction the sight line has been 
set. 
Referring to FIG. 28 again, if the button 211 has been found operated in 
step S54, then, in step S65, the processing for moving the avatar forward 
is executed. For example, if the button 211 is operated in the state shown 
in FIG. 27, an image in which the avatar gradually approaches the child 
clown is obtained. 
In step S55, if the button 212 has been found operated, then, in step S66, 
the processing for moving the avatar backward is executed. For example, if 
the button 212 is operated in the state shown in FIG. 27, an image in 
which the avatar gradually moves away from the clown while looking at the 
same. 
In step S56, if the button 213 has been found operated, then, in step S67, 
the processing for rotating the avatar to the left is executed. In this 
case, the avatar rotates to the left horizontally. If, in step 57, the 
button 214 has been found operated, then, in step 68, the avatar rotates 
to the right. For example, if the button 213 or 214 has been operated in 
the state shown in FIG. 27, an image to the left of the child clown or an 
image to the right thereof is obtained. 
In step S58, if the button 215 has been found operated, then, in step S69, 
the processing for raising the avatar is executed. In this case, an image 
in which as if the avatar is standing on tiptoe at that point is obtained. 
In step S59, if the button 216 has been found operated, then, in step S70, 
the processing for lowering the avatar is executed. In this case, an image 
in which as if the avatar is crouching at that point is obtained. It 
should be noted that, the buttons 211 through 214, if released after 
operation, the direction of the sight line is fixed at the time of 
release. On the contrary, when the button 215 or 216 is released after 
operation, the direction of the sight line is returned to the original 
reference height (the height corresponding to the avatar viewpoint). 
In step S60, if the button 217 has been found operated, then, in step S71, 
the processing for moving the avatar to the left is executed. In step S61, 
if the button 218 has been found operated, then, in step S72, the 
processing for moving the avatar to the right is executed. In this case, 
the avatar moves to the left or to the right while looking forward. This 
is a difference from the operation of the button 213 or 214, in which the 
sight line swivels. 
Thus, when the button 211 is operated in the state shown in FIG. 27 for 
example, an image in which the avatar gradually approaches the child clown 
is obtained. This clown is a child and therefore is small in stature, so 
that approaching this child clown to a certain degree results in an image 
shown in FIG. 30 for example. Namely, an image in which only the head of 
the child is shown is obtained. So, directing the sight line downward at 
that point by operating the button 220 for example provides an image in 
which the entire stature of the child clown is shown as shown in FIG. 31. 
Further, as schematically shown in FIG. 32 for example, if the sight line 
402 of the avatar 401 is directed upward by operating the button 219 and 
then the button 211 is operated, the avatar 401 moves forward (regardless 
of the sight line direction 402) in the direction 403 without being raised 
from the ground. Therefore, in this case, when viewed from the viewpoint 
of the avatar 401, an image in which as if the avatar is walking looking 
up is obtained. 
The following describes an actual processing method of changing 
above-mentioned the viewpoint position and sight line direction of the 
user in a three-dimensional virtual reality space. 
According to VRML 2.0 (The Virtual Reality Modeling Language Specification 
Version 2.0) published on Aug. 4, 1996 as a file format for describing an 
interactive three-dimensional virtual reality space and object, any 
viewpoint position of a user in a three-dimensional virtual reality space 
can be specified by changing the value of a position field of a viewpoint 
node, one of bindable nodes. Therefore, the processing operations of steps 
S55 through S61 and steps S65 through S72 of FIG. 28 are implemented by 
appropriately changing the value of the position field of the viewpoint 
node according to the operations of the buttons 211 through 218 by the 
user. 
Also, any sight line direction of the user in the three-dimensional can be 
specified by appropriately changing the value of an orientation field of 
the viewpoint node. Therefore, the processing operations of steps S51 and 
S52 and steps S62 and S63 are implemented by appropriately changing the 
value of the orientation field of the viewpoint node according to the 
operations of the buttons 219 and 220 by the user. 
For more details of the method of describing this node, refer to 
URL=http://www.vrml.org/Specifications/VMRL2.0/FINAL/spec/part1/nodesRef.h 
tml. 
It should be noted that, actually, operating the button 211 causes the 
avatar to move into the depth of the screen; but for the convenience of 
description, the avatar moves laterally (to the left) in FIG. 32. 
So far, the present invention has been described by using the Internet for 
the network 15 and by using the case in which WWW is used. It will be 
apparent that the present invention can also be implemented by using a 
wide band communication network other then the Internet or by using a 
system other than WWW. 
As described and according to the three-dimensional virtual reality space 
display processing apparatus described in claim 1, the three-dimensional 
virtual reality space display processing method described in claim 5, and 
the information providing medium described in claim 6, the display of a 
virtual reality space viewed from the viewpoint of an avatar can be made 
to look more natural with reference to the ground level (horizontal plane) 
in the real space. Moreover, the novel constitution allows observation of 
an object in a three-dimensional virtual reality space from a desired 
direction (viewpoint position) and from a desired height (sight line 
direction). 
While the preferred embodiments of the present invention have been 
described using specific terms, such description is for illustrative 
purposes only, and it is to be understood that changes and variations may 
be made without departing from the spirit or scope of the appended claims.