A Realistic Chat Environment for Virtual Avatars in Cyber Space

Graphics Application Lab

A Realistic Chat Environment for Virtual
Avatars in Cyber Space

Cyberworlds ‘08.


Soohyun Park

Pusan National University

Republic of Korea

Graphics Application Lab

2

Motivation


Chat is a crucial function in virtual worlds
.


We need a
realistic and efficient communication
framework
for multi
-
agents participating in a virtual world.

Figure 1. Current Chat System


However, current virtual world
systems have several problems
and limitations.


only 2
-
D dialog boxes
and
word
balloons


All word balloons are
orthogonally visible
to a viewer.


All dialogue texts can be read
by any avatar agent
without
regard to spatial
constraints(distance)
.

Graphics Application Lab

Main Goal


A realistic and efficient communication framework

o
Our virtual chatting system is quite different from current virtual
communicating systems.

o
If an agent wants to talk other people, then that agent should
approach within an ”audible distance”









o
We perceive that some distant agents are chatting, but cannot
identify the text contents clearly due to the distance.

3

Graphics Application Lab

4

Human
-
Cognition in Chat (1)


A virtual chat room consisting of three small subspaces
.


9 virtual chat agents are strolling in the room.


Chat agent
C

in the passageway gate is watching Groups
G
1
, G
2

and Group
G
3
.


(a) at
time
i

(b) at
time
i+1

(c) at
time
i+2

Graphics Application Lab

5

Human
-
Cognition in Chat (2)


Agent
C

is connected to Group
G
1

at
time
i
.

(a)

(b)

(c)

(d)

Graphics Application Lab

6

Human
-
Cognition in Chat (3)


Agent
C

is connected to Group
G
2

at
time
i+1
.

(a)

(b)

(c)

(d)

Graphics Application Lab

7

Human
-
Cognition in Chat (4)


Agent
C

is looking at Group
G
3

at
time
i+2
.

(a)

(b)

(c)

(d)

Graphics Application Lab


Virtual Chat Bandwidth(VCB) for two chat agents
A
a
,
A
b

.

Evaluating Chat Visibility(1)

8


Communication capacity bandwidth



Virtual Chat Bandwidth is computed
dependent on the
distance

and
viewing vector
between two agents.



The higher VCB, the greater the
extent to which two agents A and B
are able to chat with each.


Graphics Application Lab


Difference of viewing result according to the distance.


9

Evaluating Chat Visibility(2)

(a) VCB
A,BC

= 92.764

(b) VCB
A,BC

= 54.720

Chat Pair

l
ab

θ
a

θ
b

VCB

A

B

0.078

90

90

92.7644

A

C

0.078

110

45

75.6165

Chat Pair

l
ab

θ
a

θ
b

VCB

A

B

0.530

90

90

65.3595

A

C

0.525

110

45

54.7203

Graphics Application Lab

Constructing Chat Flow Graph(CFG)


A novel data structure, Chat Flow Graph (CFG)

o
Keeping track of chat dialogue is crucial.

o
Most chat programs provide
only textual history

transcripts

based
on
temporal sequence
without any explicit relationship tag.








o
A smart procedure to
manage the chatting dialogues
among
multiple agents in virtual space.

•
More flexible and superior to the previous chatting history

10

(a) Textual
history
transcript

(b) Comic Chat

Graphics Application Lab

Constructing CFG (1)


CFG(Chat Flow Graph) Construction Algorithm

11

o
Nodes denote the
messages with
timestamp and agent.

Node
←
Talk( A
i
, t
i

)
.

o
Edges are determined
through
timestamp
△
t

and
VCB
due to the
spatial information.




Graphics Application Lab

Experiment


Experiment
: One Group Chat

o
Movie


‘Dead Poets Society’

o
One group including five men is talking in a room


Experiment process

o
calculating VCB, constructing CFG, optimizing parameters and
improving CFG

12

Graphics Application Lab


The Movie ‘Dead Poets Society’


13

Chat Pair

l
ab

θ
a

θ
b

VCB

A

B

0.010

145

145

57.352

A

C

0.010

45

120

78.246

A

D

0.010

75

100

97.522

A

E

0.020

105

90

98.242

B

C

0.020

110

110

93.932

B

D

0.020

90

90

99.960

B

E

0.010

45

80

83.440

C

D

0.010

150

100

70.164

C

E

0.020

90

110

96.899

D

E

0.020

65

135

80.021

Experiment for One Group (1)

(b) VCB among agents appeared
in Figure (a)

(a) Scene of movie and
Visibility graph

Graphics Application Lab


Chat Flow Graph of Talk shown in the movie ‘Dead
Poets Society’
.

14

Experiment for One Group (3)

o
Threshold parameter
δ = 15

o
Easier for people to understand
the chat flow than before.

o
More flexible and superior to
previous chat text, which is only
kept in terms of temporal
sequence without any information
about question/answer pairing
tags.

Graphics Application Lab

Conclusion


Conclusion

o
We proposed a
realistic communication
framework
and a nice algorithm to
cluster a set of dialogue text

by
considering the spatial information
of chat agents.

o
We hope this method would be applied to the internet
chat system over virtual reality space.

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