Designing User Interfaces to Simulation Games. Designing User Interfaces to Simulation Games.
A summary of Will Wright's talk to Terry Winnograd's User Interface Class at Stanford, in 1996.
Written by Don Hopkins.
Will Wright, the designer of SimCity,
SimEarth, SimAnt, and other popular games from Maxis, gave a talk at
Terry Winnograd's user interface class at Stanford, in 1996 (before the
release of The Sims in 2000). At the end of the talk, he demonstrated
an early version of The Sims, called Dollhouse at the time. I attended
the talk and took notes, on which this article elaborates. I was
fascinated by Dollhouse, and subsequently went to work with Will Wright
at Maxis for three years. We finally released it as The Sims in 2000,
after several name changes: TDS (Tactical Domestic Simulator),
Project-X (everybody has one of those), Jefferson (after the president,
not the sitcom), happy fun house (or some other forgetable Japanese
placism). At the talk, he reflected on the design of simulators and user
interfaces in SimCity, SimEarth, and SimAnt. He demonstrated several of
his games, including his current project, Dollhouse. Here are some important points Will Wright made, at this and
other talks. I've elaborated on some of his ideas with my own comments,
based on my experiences playing lots of SimCity, talking with Will,
studying the source code and porting it to Unix, reworking the user
interface, and adding multi player support.
The anatomy of a simulation game: There
are several tightly coupled parts of a simulation game that must be
designed closely together: the simulation model, the game play, the
user interface, and the user's model. In order for a game to be realizable, all of those different parts
must be tractable. There are games that might have a great user
interface, be fun to play, easy to understand, but involve processes
that are currently impossible to simulate on a computer. There are also
games that are possible to simulate, fun to play, easy to understand,
but that don't afford a useable interface: Will has designed a great
game called "Sim Thunder Storm", but he hasn't been able to think of a
user interface that would make any sense.
On the user model: The
digital models running on a computer are only compilers for the mental
models users construct in their heads. The actual end product of
SimCity is not the shallow model of the city running in the computer.
More importantly, it's the deeper model of the real world, and the
intuitive understanding of complex dynamic systems, that people learn
from playing it, in the context of everything else about a city that
they already know. In that sense, SimCity, SimEarth, and SimAnt are
quite educational, since they implant useful models in their users
minds.
On the simulation model: Many
geeks have spent their time trying to reverse engineer the simulator by
performing experiments to determine how it works, just for fun. This
would be a great exercise for a programming class. When I first started
playing SimCity, I constructed elaborate fantasies about how it was
implemented, which turned out to be quite inaccurate. But the exercise
of coming up with elaborate fantasies about how to simulate a city was
very educational, because it's a hard problem! The actual simulation is much less idealisticly general purpose
that I would have thought, epitomizing the Nike "just do it" slogan. In
SimCity classic, the representation of the city is low level and
distilled down compactly enough that a small home computer can push it
around. The city is represented by tiles, indexed by numbers that are
literally scattered throughout the code, which is hardly general
purpose or modular, but runs fast. It sacrifices expandability and
modularity for speed and size, just the right trade-off for the
wonderful game that it is. Some educators have asked Maxis to make SimCity expose more
about the actual simulation itself, instead of hiding its inner
workings from the user. They want to see how it works and what it
depends on, so it is less of a game, and more educational. But what's
really going on inside is not as realistic as they would want to
believe: because of its nature as a game, and the constraint that it
must run on low end home computers, it tries to fool people into
thinking it's doing more than it really is, by taking advantage of the
knowledge and expectations people already have about how a city is
supposed to work. Implication is more efficient than simulation. People naturally attribute cause and effect relationships to
events in SimCity that Will as the programmer knows are not actually
related. Perhaps it is more educational for SimCity players to
integrate what they already know to fill in the gaps, than letting them
in on the secret of how simple and discrete it really is. As an
educational game, SimCity stimulates students to learn more about the
real world, without revealing the internals of its artificial
simulation. The implementation details of SimCity are quite interesting
for a programmer or game designer to study, but not your average high
school social studies class. Educators who want to expose the internals of SimCity to
students may not realize how brittle and shallow it really is. I don't
mean that as criticism of Will, SimCity, or the educators who are
seeking open, realistic, general purpose simulators for use in
teaching. SimCity does what it was designed to and much more, but it's
not that. Their goals are noble, but the software's not there yet. Once
kids master SimCity, they could learn Logo, or some high level visual
programming language like KidSim, and write their own simulations and
games! Other people wanted to use SimCity for the less noble goal of teaching people what to think, instead of just teaching them to think.
Everyone notices the obvious built-in political bias, whatever
that is. But everyone sees it from a different perspective, so nobody
agrees what its real political agenda actually is. I don't think it's
all that important, since SimCity's political agenda pales in
comparison to the political agenda in the eye of the beholder. Some muckety-muck architecture magazine was interviewing Will
Wright about SimCity, and they asked him a question something like
"which ontological urban paridigm most influenced your design of the
simulator, the Exo-Hamiltonian Pattern Language Movement, or the
Intra-Urban Deconstructionist Sub-Culture Hypothesis?" He replied, "I
just kind of optimized for game play." Then there was the oil company who wanted "Sim Refinery", so
you could use it to lay out oil tanker ports and petrolium storage and
piping systems, because they thought that it would give their employees
useful experience in toxic waste disaster management, in the same way
SimCity gives kids useful experience in being the mayor of a city. They
didn't realize that the real lessons of SimCity are much more subtle
than teaching people how to be good mayors. But the oil company hoped
they could use it to teach any other lessons on their agenda just by
plugging in a new set of graphics, a few rules, and a bunch of
disasters. And there was the X-Terminal vendor who wanted to adapt the
simulator in SimCity into a game called "Sim MIS", that they would
distribute for free to Managers of Information Systems, whose job it is
to decide what hardware to buy! The idea was that the poor overworked
MIS would have fun playing this game in which they could build networks
with PCs, X-Terminals, and servers (instead of roads with residential,
commercial, and industrial buildings), that had disasters like
"viruses" infecting the network of PC's, and "upgrades" forcing you to
reinstall Windows on every PC, and business charts that would
graphically highlight the high maintanence cost of PCs versus
X-Terminals. Their idea was to use a fun game to subtly influence
people into buying their product, by making them lose if they didn't.
Unlike the oil company, they certainly realized the potential to
exploit the indirect ways in which a game like SimCity can influence
the user's mind, but they had no grip on the concept of subtlety or
game design.
On the game play: Usually
the game is separate from the simulation. Games can be based on
conflicts and goals, that are external to the simulation itself. The
simulation goes on doing its thing, and the user can play different
games with their own sets of goals. The simulation does not consider
fires spreading between buildings to be an error condition or a source
of conflict -- that's just the way the simulator's supposed to behave.
But the user might, unless the game they're playing is pyromaniacal. The design of the game play has a lot to do with the user's model
of the system, and SimCity elegently supports a number of different
user models, games, and toys in one program. You can use the
terraforming tools and natural features to play with it like a sandbox
or landscaping toy, without even starting the city simulation phase of
the game. You can even use it as a painting tool, drawing colorful
designs and cartoons with land, water, roads and buildings. SimCity
comes with several scenarios with different conflicts and goals, and
has a menu of disasters you can invoke to destroy your city, or
challenge yourself to recover. You can start your own city from
scratch, and develop it in any direction you want. A satisfying feature
of SimCity 2000 is the ability to put signs in your city, to name roads
and buildings and parts of town. How else could you personalize a
simulated city? There was some interesting discussion about using SimCity as a
medium for story telling: encouraging people to imagine far beyond the
bounds of what the computer is able to simulate. You can build cities
to empathise with, and tell stories about them, about their people,
culture, buildings, and history. A class of students could label
different parts of a city, and each person could tell a story about a
different part, that interacted with the stories going on in
neighboring parts of the city. Then they could make a web site with the
downloadable city, and an image map of the whole city, linking to all
the stories on web pages, with screen snapshots of their neighborhoods,
and lots of hypertext links between each story. This way each student
could colaborate with several others to write a web of interconnected
stories, all about the same city!
On the user interface: Will
demonstrated the close up and overall views in SimEarth, and showed how
SimCity 2000 integrated these with zooming in one window. He talked
about information density and screen size.
Post Morta: After
designing SimCity Classic, then SimEarth, then SimAnt, then SimCity
2000, here's one way Will compares them: With SimCity Classic as the
standard against which to measure, SimEarth was too complex, SimAnt was
too simple, and SimCity 2000 was just right.
SimEarth: SimEarth and
SimAnt did not support the same level of creativity and personal
imprinting that SimCity does. With SimEarth, anything you do is quickly
wiped out by continental drift, erosion, and evolution; you can walk
away from it for a while, come back later, and it will have evolved
life or shriveled up and died without you, looking pretty much the same
as if you had slaved over it for hours. It was too complex a simulation
for people to grasp or effect in a satisfying way. The time scale slows down as the game progresses, from geological
time, to when life appears, to when intelligence appears, to when
technology is developed. There was some trouble conveying this to the
users. One thing that supported the notion of time scale is how the
view controls along the bottom of the global map were ordered in a
temporal progression, in the order you'd need to use them, from the
continental drift display, to the technology display.
SimAnt: SimAnt had
just the opposite problem -- it was too simple, but that made it
popular with younger kids. Like SimEarth, it didn't support creative
personal imprinting as well as SimCity, since one ant farm looks pretty
much like any other, and ants are quite disposable and devoid of
personality... The educational point of SimAnt is to teach about the
emergent behavior of multi-cellular organisms like ant colonies. I
think SimAnt would make a fascinating large scale multi player game.
SimCity Classic: I haven't typed this in yet. It's been endlessly rehashed elsewhere and deserves a whole article in itself.
SimCity 2000: I
haven't typed this in yet, either. When I write this in 1996, I skipped
over SimCity because wanted to get on to writing the following while it
was fresh in my mind:
Dollhouse: Imagine
zooming into SimCity 2000, all the way down to the street level, and
seeing little people walking around, waving at each other, asking for
spare change, jumping up and down, gesturing, interacting with each
other, living and playing in rooms with furniture and active objects,
and you're one of them! Will showed me Dollhouse several years ago, and it was amazing
then, and even more so now. It's not a product yet, but he's been
working on solving some very hard problems. He's trying to give the
people who walk around the world seemingly rational behavior. Dollhouse takes the third person view (looking down on your
character), instead of the first person view (looking out of the eyes
of your characters). You view your character from above, with a 45
degree orthographic view like SimCity 2000 uses to display buildings.
Will has found that it works quite well, since you can see yourself as
others see you, as well as seeing other people around you. If there are
a bunch of people gathering around some interesting person or place,
it's easy to tell what's going on, and navigation is simple and direct.
It doesn't suffer from the disorienting navigational problems that a
first-person view like Doom imposes. Being able to see yourself as
others see you seems to make interpersonal interactions involving body
gestures much easier.
PostScript:
%!
Since I originally wrote this in 1996, Maxis released Dollhouse as
The Sims in 2000, and it quickly became much more popular than anyone
expected. But in the context in which this was written in 1996,
Dollhouse was so drastically different than the first-person-shooters
that dominated the market, that it wasn't obvious it would ever be
successful. It questioned and reformulated many of the widely-held
assumptions about virtual reality games: the audience (both sexes and
all ages), the person and perspective (overhead god view instead of
first person), direct navigation control (routing and action queue
instead of forward/back/turn), mapping of players to characters (player
switches between many characters instead of one-to-one), the overall
approach to AI (object centric, extensible plug-ins, interacting with
autonomous agents), programming tools (SimAntics visual programming
language, instead of text script), and the style and motivation of game
play (creative sandbox and social dynamics).
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