Digital Games as Simulations
Katrin Becker & J. R. Parker
Digital Media Laboratory
Department of Computer Science
University of Calgary
1 403 220 6784
parker@cpsc.ucalgary.ca
Keywords: video games, discrete event simula-

tion, methodology.

Abstract

On a computer, all games are simulations, but
not all simulations are games.
With the recent and rapidly growing interest in
digital games, it has become important to examine this
claim in detail. In this paper, the authors will examine
the dichotomy between modern digital games and the
more traditional view of simulations, and what
implications this has for the development of both
‘pure’ simulations as well as games.

INTRODUCTION
Isn’t the connection between games and
simulations obvious? For much of the simulation
community it appears so, but other disciplines make
other connections and use different terminology.
What difference does it make, anyway? Well, in many
instances it does not matter much or at all. And yet, if
computer games are simulations, then tools and
techniques are being developed in the games domain
that would be of interest to simulation practitioners of
all stripes, and we need to know how to find them. It
may also be valuable to avoid a duplication of
terminology, thus making the literature of both
subjects more accessible.
The relationship of games to simulations is of
particular interest in the area of “serious games”,
which are games whose primary purpose is something
other than pure entertainment. This area includes
games created for training and other educative
purposes, games used for advertising, games designed
for health-related, medical, and military applications
as well as games used as vehicles to effect social
change. Several elements set these kinds of games
apart from commercial entertainment games. This

includes, but is not limited to the diversity of experts
involved in the development of these applications, as
well as the degree of influence they hold over their
design and implementation. This difference is one that
makes a clear understanding of the connection
between games and simulations crucial. Not only do
different expert communities use different vocabulary
to express different ideas; they sometimes use the
same terminology to express different ideas[1], and
this causes difficulties.
Simulation has been an active application area of
computer technology almost since the very beginning
of computers, yet with a very few exceptions, CS
professionals still seem to have a view of simulation
that is different from that of most other interest
groups. One noteworthy exception comes from the
military, and the relationship between simulations,
games, and training has been a long and fruitful one
for them. Other groups do not share the same comfort.
With more and more attention being paid to the use of
games in educational and training situations, the view
of simulation held by educators [2] is bound to have a
greater impact on how simulations will be developed
and used as well as on research and development in
simulation.
In education, many view simulations as
necessarily involving the simulation of realistic and
real-life systems, and make sweeping assumptions
about how simulations get used. This includes notions
that fidelity and realism in simulations are essential to
effective learning, notions that learners do not use
games in ways other than those intended (which, by
implication makes them less effective than
simulations), and that winning always takes
precedence over exploration in games. These notions
tend to limit the efficacy of all simulations including
games, whereas a better understanding of how games
are in fact merely a subset of a larger category of

simulations affords opportunities for exchange of
knowledge and a broadening of the view of games as
an area of focus for emerging methodologies and
tools.

THE NATURE AND STRUCTURE OF A
COMPUTER GAME
Although a significant fraction of the North
American population has played a video game, very
few of those individuals have any real appreciation of
what kind of technology a game depends on, or even
necessarily that a game is a software object.
Looked at from the perspective of a designer or
developer, a computer game can be described as a
real-time system that uses input from a person with a
keyboard, mouse or special purpose device (E.G.
joystick) to control a simulation and a graphical and
audio display. A certain degree of (artificial)
intelligence is needed to control independent
graphical entities with which to interact (E.G.
opponents) and/or there can be a network interface
with which to communicate with other real entities
(network opponents). There is usually a significant
amount of multimedia data associated with a game, in
the form of graphics, video, and sound. Finally, game
consoles (E.G. Playstation 2) and recent PCs can use
multiple processors, and so a measure of parallel
computation is sometimes used to accelerate play.
Whether that is so or not, it is always true that an
efficient implementation is always required - games
constantly push the available resources, both
processor speed and memory, of modern PCs to the
limit.
A distinction should be made at the outset
between games that are implemented on the computer,
such as chess and solitaire, and games that require a
computer in order to be played, like Tetris and Doom.
It is the latter category that will be referred to as
computer games. It is this class of games that requires
the significant technology of the modern computer,
and that is the study of so much recent attention to
define rational methods of design.

A Quick Walkthrough of a Game
When a computer game begins executing, it
loads the initial set of media files (sounds, images) as
it displays a set of splash screens that are either purely
decorative or that are asking the user for input
(selection of player parameters and so on). The next

step is sometimes to play a short video and perhaps to
enter a tutorial that explains the rules and the
operation of the interface.
When game play begins, simulation time begins
as well. It’s generally true that game/simulation time
advances at the same rate as real time, and that the
game proceeds whether the player is actively
participating or not. For example, in a racing game
once the race begins the player can choose to race,
follow another car, stop, or drive backwards – the
other cars will continue to race each other, and time
will advance. The graphical display is updated quickly
enough so that the screen appears to be a window into
the simulated world, and object motion appears to be
continuous. This requires a minimum display rate
(frame rate) of 24 images per second, but faster is
better. Moreover, the computation associated with the
graphical display takes most of the time between each
frame.
So, in each 1/24 of a second, here what has to be
done:
- Determine where all of the objects
should be.
- Detect any collisions and their time
and result.

20%

- Determine how the objects ought to
behave, given their current system
state, and what the next step in
their plan should be.
- Start playing any sounds resulting
from actions.

15%

- Determine which frame in each animation should be next.
- Determine the camera position.

8%

- Render all objects from the current
camera position

57%

The order matters – objects need to be positioned
before being drawn, and position often depends on
interactions with other objects. Also, it should be clear
that a computer game is a discrete event simulation, in
the sense that the state of the simulation is displayed
at regular intervals, and continuous processes need
only to be calculated at those times.

Essentials of Digital Simulation

as we model them.

Let’s begin with a good definition of a computer
(digital) simulation, one that is non-threatening and,
with any luck, uncontroversial. Wikipedia defines:

Fidelity

A computer simulation or a
computer model is a computer
program that attempts to simulate an
abstract model of a particular
system. … Traditionally, the formal
modeling of systems has been via a
mathematical model, which attempts
to find analytical solutions to
problems that enable the prediction
of the behaviour of the system from
a set of parameters and initial
conditions.
This definition unfortunately uses the word
simulate. What simulate means in that context is to
offer a working analog, in software, of the larger
original system or model that reacts in all practical
ways like the original, but in an artificially provided
environment. Consider a spring hanging from the
ceiling with a weight attached to the lower end.
Pulling the weight down a few inches and then letting
go causes the weight to be pulled up by the spring to a
maximum height, then falling again, and so on in an
oscillating manner. That’s the real world.
The model is an equation that will provide the
position of the weight as a function of time given all
of the parameters of the system: the stiffness of the
spring, the magnitude of the weight, and the amount
of the initial displacement (this ignores air resistance
and other minor effects, and perhaps more aspects of
the real situation).
The simulation is a computer program that codes
the equation of the model and allows an experimenter
to enter the parameters. The simulation then builds a
virtual environment within which time appears to
pass, and the model appears to govern the motion of
the weight on the spring. There is no weight and no
spring, only the model and perhaps a graphical
version for display on a computer screen. The passage
of time in the simulated virtual world is under
programmer control, and bears no necessary
connection to the passage of time in the real world. A
virtual world has been defined in which physical laws
are what we say they are, and in which objects behave

The term fidelity refers to the accuracy with
which the simulation represents or models the
situation being simulated. Sometimes the simulation
is intended to be a model of the real world, in which
case what we mean by fidelity is clear enough – it is
how well the simulation resembles the real situation.
A difficulty is encountered if we become too religious
about what we mean by real. Common usage in the
field of educational technology, for instance, has it
that simulations must simulate the real world, or they
are not actually simulations.
On the other hand, real is not always what a
simulation is modeling. A pretty clear statement of
this has been made by the Defense Modeling and
Simulation Office (DMSO) who refer to the system
being simulated as the simuland, and clearly make a
distinction between a simuland and reality:
However,
simulands
are
not
necessarily
the
“real
world,”
because many simulations do not
intend to represent situations found
in current reality. For example, they
may represent the performance of
proposed weapon systems in a
hypothetical battlefield.

Virtual Worlds
So, it appears that both games and simulations
define a mathematical construct that bounds the
possible properties and activities of the objects being
described. This would be a fair description of a virtual
world. What is possible in these worlds is not
restricted by the bounds of the known universe: the
gravitational constant could be varied, for instance, or
a substance that is massless but very strong could be
created. In the case of many simulations, the purpose
is to predict the results of an experiment, to try to
define the end state of a situation. In some cases the
simulation is intended to determine which set of
parameters will yield a particular outcome.
A game often has as its goal to entertain. People
often find a game entertaining if it offers a virtual
world that has many real aspects, probably because
the real world is so familiar. If time moves too quickly
or slowly it is unnerving, and if gravity is too strong
then our instincts are all wrong. It may be useful at
this point to examine a few of the major genres of

computer game and see how they are, in fact,
simulations.

Video Game Genres
A genre is a type or class of an object, and with
respect to computer games there are many recognized
classes. The essential ones are:
²
²
²
²
²
²
²

Action games, including first person
shooters (FPS) and fighting games.
Role-playing games, including real time
and turn based versions.
Simulators, within which the sports genre,
flight simulators, and driving games reside.
Strategy games, including military games.
Puzzle games, including pinball and tetris
type games.
Adventure games, which sometimes are
text based.
Activity based games such as Dance,
Dance Revolution, that are based on
external sensors that detect motions of the
player.

Genre Activities
Shooters and fighting games require that the
model universe represent reality in the sense that
blows and weapons have the effect that you would
expect, and physical activities including collisions
must behave as they would in the actual world. They
are in that sense a simulation of a restricted part of the
real world.
Role-playing games can be turn based, and so
might not have a real time aspect. Other role-playing
games have the characteristic of shooters, in that the
perspective is that of the individual, and the goals are
local and tactical at the moment but support an overall
global goal that results in winning the game. Like
shooters, these require a fair model of the physical
universe in order to be entertaining, or at least a
consistent model of a fictional universe.
Sports games and driving games are the most
obvious simulations in the group. Physics takes a huge
role in these games, as collisions are a key feature and
real-time activity is almost always essential. Flight
simulators are amongst the oldest in this type. They
have been used to teach flight skills for a long time, in
some form, and the simulation (for example, a Link

trainer) predates the video game. Flight sims can be
made into first person shooters quite easily (E.G.
Crimson Skies).
Strategy games are in many ways a more abstract
representation of the world, sometimes showing
terrain or military units as icons. In this way they can
be thought to be a high level simulation, giving a more
strategic view than a tactical one. Indeed, this is the
source of the name: strategy game. Their value is that
the details associated with individual objects is
sacrificed in favour of a higher level perspective.
Frequently the issues are those of logistics, position,
and general strength levels and goal selection rather
than specific individual strengths or skills. The
simulation is at a higher level than is the shooter, but
has the same characteristics: the world must be a
consistent model of a universe in order to be effective.
Puzzle games fall into a few categories. Some are
clearly simulations of a physical game, like the
computer pinball games, and so might not fall into the
video game definition as defined here at all. Others,
such as the famous Tetris, contain isolated parts that
are simulations: geometry in the abstract and gravity,
for instance. This class of game may well be the most
interesting, and is certainly the hardest to get a firm
grasp on. If there is a counter example to the ‘games
are simulations’ theorem it is in this class.
Tetris is a good example of what I would call a
pure video game. There can’t even be an
approximation of Tetris without use of real-time
interactive technology. Kids play shooting games with
water guns, and do role-playing with each other;
strategy games have an origin in certain kinds of
board games. However, the nearest non-computer
game I know to Tetris is Soma, which was a 3D
geometric puzzle that became popular in the late
1960’s and 1970’s (a computer version can be found
on the internet at http://yavsoft.com/soma/).
Adventure games consist of a model of the
physical environment and how that interacts with the
player. In that sense, they are obviously simulations,
but the degree of interaction and the resolution of the
display have a large amount of variation, from simple
text descriptions to graphics and positional sound.
Finally, activity based games are often direct
measurements of game-like activities that would take
place in real life. These games always require extra
input devices: microphones, cameras, pressure
sensors, and so on, so as to create an input from user

motions and activities. This is almost an identity
simulation, with the game platform relegated to
keeping track of performance.

WHAT CAN SIMULATIONS TAKE FROM
GAMES?
Games constitute the single biggest influence on
the advancement of PC hardware in the last decade,
and this includes processor speeds, storage capacities,
transfer rates, graphics capabilities and sound. The
majority of after-purchase hardware upgrades are
used to enhance gameplay [7]. With the ever
increasing popularity of games also comes a higher
profile for the role of simulations in general. Whether
we wish to admit it or not, computer science owes
much to the consumers’ ever-increasing demands for
more realistic, immersive game experiences. Nearly
half of all freshman entering the field cite an interest
in games development as a significant factor in their
choice of major [8].
Until recently, the games industry has been
largely discounted by the more ‘serious’ and rigorous
scientific community. The data reliability and realworld performance essential in scientific visualization
and visual simulations [9] and the kinds of
environments implemented in games were too
disparate to suggest that the simulation community at
large could benefit from game technology, at least, in
terms of software and design. However, the demands
of present-day high end simulation and the kind of
environments supported by games like Elder Scrolls:
Oblivion are converging to the point where dual
purpose games like Full Spectrum Warrior have
emerged. This game, which was first released in 2003,
has been produced in two versions: a scaled-down
version produced for commercial release, and a
substantially more involved one designed for and used
by the U.S. Department of Defense as part of its
training program. Other military groups, such as the
Singapore Armed Forces are also actively exploring
the viability of using commercial off the shelf (COTS)
games for training [10].
State of the art technology in games can now be
used to inform design in more serious simulations,
from user interfaces and navigation schemes to file
formats. Perhaps as important as the technology of
games is the knowledge of the psychological issues
surrounding them. Especially when simulations are
used in training applications, the concepts of flow [11]

and intrinsic motivation [12] are important in
understanding how to create interactive software that
accomplishes its stated goals. Flow is a state of human
perception, one in which the person is completely
immersed or absorbed in their activity. It has been
studied more fully since the advent of video games,
mainly because game developers seem to understand
how to create that state in players using the relatively
limited multimedia tools at their disposal. Intrinsic
motivation has been described as a motivation to
participate in activities that maintain or agree with a
person's self-conceit; in more plain terms it refers to a
desire to engage in an activity for its own sake. People
who are intrinsically motivated work on tasks because
they find them enjoyable, and not necessarily for
another kind of reward.
Are these theories the reason that some players
find video games so addicting? Perhaps. However,
there is a recent theory that the brain desires sensory
information because it craves the natural opiates that
the sensations create [13]. This would imply that
interactive game-based methods are a better way to
encourage a greater participation in the defined
simulation activity in some groups of people. The
latter theory may explain sense of pleasure that many
players receive from game play. Training sims can
learn much from this if they are to continue to be
successful.

REFERENCES
[1] Shaw, Mildred and B. Gaines, Comparing Conceptual
Structures: Consensus, Conflict, Correspondence and
Contrast. 1989.
[2] Alessi, S.M. and S.R. Trollip, Multimedia for learning:
methods and development. 3rd ed. 2001, Boston: Allyn
and Bacon. xi, 580.
[3] Parker, J.R., Loose, K., and Verheyde, N., Objectives and
Outcomes of a Senior Course in Computer Game Programming, Western Canadian Conference on Computing

Education (WCCCE), Mt. Royal College, Calgary,
Alberta, Canada. May 4-6, 2006.
[4] Parker, J.R., Start Your Engines - Developing Driving
and Racing Games, Paraglyph Press, 2005.
[5] Parker, J.R., Cyber GameSpace: Simulating the Unreal,
Simulation and Other Re-enactments: Modeling the
Unseen Symposium, Banff, Alberta.
[6] J.R. Parker, Sonny Chan and Jeff Howell, OceanQuest:
A University-Based Serious Game Project, Digital
Games Research Association Conference (DiGRA
2005) Vancouver, BC. June 16-20, 2005.