329
19
AnEgocentricMotion
ManagementSystem
Michael Ramsey
Ramsey Research, LLC
Between the motion
And the act
Falls the shadow.
—T. S. Eliot
The egocentric motion management system (ECMMS) is both a model for agent
movement and an application of a behavioral theory. Any game that features
agents (e.g., animals, soldiers, or tanks) that move around in a 3D scene has a
need for an agent movement solution. A typical movement solution provides
mechanisms that allow for an agent to move through a scene, avoiding geometry,
all the while executing some sort of behavior.
This article discusses not only how focusing on the agent drives the immedi-
ate interactions with the environment but also, more importantly, that by gather-
ing some information about the environment during locomotion, we gain the
ability to generate spatial semantics for use by the agent’s behavior system. Por-
tions of the ECMMS were used in a cross-platform game entitled World of Zoo
(WOZ), shown in Figure 19.1. WOZ is an animal simulator that requires various
zoo animals to move through their environments in an incredibly compelling
manner while the players constantly alter the environment. So the proving ground
for this system was in an environment that could be changed around the agents at
any particular moment.
330
Con
v
importa
n
mind is
h
facilitat
e
dreadin
g
havioral
expect t
h
percept
u
states o
f
user of
n
b
ehavio
r
have a c
sire to
b
enough
t
they fit
t
One
is that
w
in an ap
p
is not o
p
purpose
f
animati
o
imbue o
u
compon
e
should
b
F
v
incing beha
v
n
t as what is
p
h
ow we con
t
e
s
p
erceived
g
and percept
u
coordinatio
n
h
e user to mi
m
u
al mindreadi
n
f
others, and
w
n
ot only the a
g
r
, also know
n
riterion for
u
b
elief, then i
t
t
o represent
t
t
ogether.
of the highe
r
w
e ideally wo
u
p
ropriate ma
n
p
en for inter
p
f
ul manner.
T
o
n, and artifi
c
u
r agents wi
t
e
nts that for
m
b
e about the p
F
i
g
ure 19.1. S
c
v
ior is not a
p
erceived by
rol the perce
p
intent. Bur
m
u
al mindrea
d
n
—this gets
u
m
ic the agen
t
n
g is slightl
y
w
e accompli
s
g
en
t
’s intend
e
n
as propositi
o
nderstanding
t
is likely t
h
t
he states of
r
-order goals
u
ld like to o
b
n
ner. What i
s
p
retation is t
h
T
o help facil
i
c
ial intelligen
t
h these char
a
m
the system
r
ocess throu
g
19.An
E
c
reenshots fro
m
one-way stre
the user. The
p
tion of an a
g
m
edez [2007]
d
ing. Simple
m
u
s nowhere,
a
t
’s behavior i
n
y
different in
t
s
h this by pr
o
e
d state but i
t
o
nal attitude
s
behavio
r
. If
h
at the beha
v
a behavio
r
—
when desig
n
serve an age
n
s
appropriate
h
e desire that
i
tate this, we
ce a
r
e inter
w
a
cteristics. A
s
and its resul
t
g
h which thes
E
gocentricM
m
World of Zo
o
e
e
t
—what th
e
e
immediate
q
g
ent in a sce
n
delineates
b
mindreading
a
s we are o
b
n
order to un
d
that the focu
s
o
viding mec
h
t
s eventual st
a
s
). This is cri
t
they witness
v
ior is justifi
—
humans ne
e
n
ing a motio
n
n
t in a scene
is open to in
t
we perceive
need to un
d
w
oven into a
s
s
such, this c
h
t
ant end prod
u
e results wer
e
otionManag
o
.
e
agent does
i
q
uestion that
c
n
e in such a
w
b
etween sim
p
is fundame
n
b
viously not
d
erstand it.
H
s
is on the p
e
h
anisms to in
f
a
te (i.e., goal
-
tical because
the attributi
o
able. It’s si
m
e
d to underst
a
n
manageme
n
responding t
o
t
erpretation,
b
the agent ac
t
d
erstand how
s
hadowy sub
s
h
apte
r
focus
e
u
ct, but the t
a
e
obtained.
ementSyste
m
i
s just as
c
omes to
w
ay that
p
le min-
n
tally be-
going to
H
owever,
e
rceptual
f
orm the
-
directed
humans
o
n of de-
m
ply not
a
nd how
n
t system
o
stimuli
b
ut what
t
ing in a
physics,
s
tance to
e
s on the
a
keaway
m
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