Game Development Reference
In-Depth Information
12.6 TYPES OF NPCS AND HOW THEY CAN BE USED IN VIRTUAL ENVIRONMENTS
To understand how NPCs support the visual depth and diversity of an environment, put on your walking
shoes and take a 20-minute stroll through your real-world local marketplace, mall, or public park. While you
are walking, take note of the people around you. Who is standing still, and why? Are they selling something,
or maybe looking at a map? Is there a group of them chatting together, blocking trafic on the sidewalk?
Do you see a couple sitting on a bench together, or maybe an old lady and her ancient poodle enjoying the
afternoon sun? Inspiration and information about how to populate a street scene are right outside your door,
and you should tap that resource for your virtual world scenes.
12.6.1 s
eTTing
The
“s
Tage
”: p
roper
B
ehaVior
in
y
our
npC
s
Behavior, just like costumes or clothing, is period speciic. When you start to think of the crowd design for
your virtual space, ask yourself: What kinds of behaviors are appropriate for the time period I am represent-
ing, and how can I relect that in my NPC animations?
Also, you will have to consider how many of these virtual background actors the server supporting your
virtual environment will be able to control, especially if you have a busy sim full of running scripts and
people-run avatars with lots of attachments.
Furthermore, you need to ask, how does adding NPCs to my sim enhance the visitors' experience of the
environment? Do the NPCs in my region make them feel like the “leading actors” there?
12.6.2
C
iTy
of
u
ruK
: a s
umerian
T
oWn
C
omes
To
l
ife
A signiicant example of NPC utilization in Second Life is the city of Uruk (http://www-staff.it.uts.edu.au/~anton/
Research/Uruk_Project/). In this sim, the daily life in the ancient Sumerian city of Uruk, circa 3000 BC, is
reenacted by numerous NPCs, playing out the roles of ishermen, potters, slaves, and royalty. Created in 2008
and ongoing both in Second Life and in OpenSim, this project was started with the collaborative efforts of
Dr. Anton Bogdanovych, PhD, from the University of Western Sydney (UWS) and Alex Cohen, the senior
digital information strategist at the U.S. Department of Energy. In Figure 12.2, you will see images taken from
Uruk that show the resident avatars performing daily tasks such as pot making and ishing and an overall view
of the city as it stands today in Second Life (http://maps.secondlife.com/secondlife/FAS/184/121/28).
12.6.3 r
oles
T
hose
npC
s
C
an
p
lay
How can we utilize NPCs on a sim? Let us count the ways. Here are some basic categories of NPCs, separated
by their level of artiicial intelligence (AI) and interaction:
1.
Non-AI:
mannequins, crowds for street scene, “regulars” at a bar or tavern, spectators, entourage,
palace staff, village inhabitants, angry mob, lash mob, pacers for exercise programs, “hares” for
people-based “hounds” to chase, weapons targets
2.
With partial AI:
receptionist, tour guide, companion, ensemble actor, maître d'
3.
With programmed/chatbot AI:
language tutor, teacher, presenter, therapist, near “background” actor,
interactive actor/performer, bartender
