Research Synthesis

Mixed Reality game design introduces unique challenges in how play
interfaces are deployed in their environment. The formal elements of
these interfaces are defined by the spaces in which they are used,
since capturing the essence of Mixed Reality requires a conversation
between the systems’ physical environment and the digital systems
that users interact with. In the design documents for the Double
Dribble, CitiTag and Touch-Space games, the way feedback is presented
to users is defined primarily by the space in which the systems are
deployed. The Social and Physical Interactive Paradigms and Human
Factors in Mixed Reality papers support this by describing Mixed
Reality system design in terms of very clear physical and ergonomic
design constraints. By comparing the environmental design
considerations of games developed for Mixed Reality environments in
the context of the technical and human factors required to deploy
Mixed Reality interfaces, a clear design focus will emerge for how
these types of games can be designed and deployed for a particular

The Double Dribble game features a digital game of basketball that sports
fans can play over the internet while listening to an audio feed of
live NBA games. Where the conversation between the physical and
digital occurs in how the games are scored. The digital game being
played by the fans is scored alongside the score of the live (or
pre-recorded) NBA game. The digital game score is added to the live
game score, with the addition of a non-player character who acts out
the live game scoring in the virtual space as the live game score
increases. This "ghost player" mechanic augments the
experience of participating in a computer game experience with input
from a live sports event. The researchers conducted a prototyped
experience using an actual game of basketball played in a gym that
was synced to a prerecorded audio feed of an NBA game. The
researchers found that players were often frustrated by the breaks in
their play induced by the input from the NBA game. This frustration
occurs because the experience of playing a "real" game of
basketball captures more attention from players than the audio feed
of the NBA game. In designing Mixed Reality games for social
gathering places, I will avoid this spatial disconnection by keeping
limiting the external influence of the gameplay to computational
enhancements that will have a clear correlation with the direct
actions of the players in the same physical space.

During the prototyping and testing phase of the CitiTag project, the
researchers found a number of emergent behaviors exhibited by
players. These behaviors arose out of limitations and quirks of the
technologies used to implement the Mixed Reality system, as well as
the rules of play imposed by the designers. Players cooperated and
ganged-up on other players in areas where the project’s GPS reception
was known to be temperamental. This often allowed larger groups to
overcome a single player of greater skill, simply because of the
lagging of the GPS technology. Players of CitiTag also began to raise
their hands when tagged, to indicate to other players that they
needed to be untagged by a teammate. While such physical indications
are necessary in CitiTag’s large, open environments, I hope to
utilize the same technological and gameplay quirks in designing for
social gathering places, that require players to communicate amongst
one another (as well as with spectators). While these open holes in
CitiTag’s gameplay allowed for interesting emergent behavior, I hope
that in designing Mixed Reality games for a more constrained physical
environment, I can minimize the amount of technical glitches that
occur in the conversation between the digital and real spaces of the
games. I hypothesize that players encountering technical glitches in
more constrained and competitive environments will bring about more
frustration that the types of interesting emergent behavior exhibited
by the CitiTag players.

Compared to the previous two design documents, Touch-Space presents a more
segmented approach to Mixed Reality entertainment. While Double
Dribble and CitiTag present real-time interactions that are
influenced by both digital and real forces, Touch-Space presents a
physical environment (an enclosed room) that is augmented by virtual
spaces, which include discoverable games. The designers of
Touch-Space clearly demarcated three stages in the gameplay that
users would experience: Physical Land Exploration Stage, Virtual Land
Exploration Stage and Virtual Castle Exploration Stage. The first two
stages lean more towards the field of Augmented Reality, while the
third is a Virtual Reality experience. In designing Mixed Reality
games for social gathering spaces, I plan to create a real-time
system that combines these user experience stages into a singular
game mechanic. Whereas Touch-Space consists of a platform where
virtual games can be embedded in real space, I plan to introduce a
physical/”real” game that is influenced by digital space, thus
encompassing the players’ experience into a single game space.
Despite this clear differentiation between approaches, I feel that
the clear definition of players’ experiences in Mixed Reality spaces
provides a clear framework for how players will become comfortable in
Mixed Reality settings. I hope to use the influence of these
distinctions in designing the static, and introductory states of the
game. That is to say that the game surface should afford certain
types of interactions, even when nobody is playing it. In addition,
before the competitive gameplay begins, I will introduce a “sandbox”
mode, where players can, if they want, experience the nature of play
before scoring begins.

and Physical Interactive Paradigms for Mixed-Reality Entertainment

shows a number of different Mixed Reality interfaces, and classifies
them based on the interactive paradigms they employ. A number of
projects utilizing similar models to Double Dribble, CitiTag and
Touch-Space are analyzed, as well as a project called Magic Land,
that more closely resembles an interface design that could be
deployed in social gathering spaces. The Magic Land project requires
a single player to look into a device that is position and
rotation-aware, that augments the player’s view with digital elements
when they are looking at a table with devices that are tracked with
Computer Vision. This system closely matches the needs of a system
for real-time, competitive gameplay in social gathering places with
the exception that the Magic Land system can only be used by one
person at a time. By utilizing imagery that can be viewed on a flat
surface, the game can be played and observed by many people at once.
While the Magic Land system can be used in various light conditions,
social gathering places like bars have darker atmospheres that afford
digital projection that can be viewed by many people at once.

Human Factors paper describes a number of factors relating to the
projection of digital imagery onto, and capturing digital information
from, the physical world. Where the previous papers included a number
of practical assumptions about environments selected for Mixed
Reality applications, this paper remains abstract about the factors
inherent in the technology. Despite this intended objectivity, the
paper often alludes towards applications in outdoor environments, as
well as ego-centric approaches in visual input. While these
implications make it difficult to extract usable criteria for the
application of Mixed Reality in clearly defined spaces withing areas
of social gathering, the considerations presented in Human Factors
can assist in creating a more immersive experience. In particular,
the sections on matching luminance, contrast and resolution of
digital images to their real world counterparts will influence how a
Mixed Reality game will present its imagery to the user. Whereas
Human Factors presents these considerations as limitations to more
open-ended systems of Mixed Reality, games designed for specific
contexts and physical spaces will be able to closely match the
digital worlds they produce to the external environments. This I
believe, will create a more engaging game experience for users who
are familiar with the environments they choose to gather in.

approaching these papers, a clear picture of the environmental
considerations for designing Mixed Reality systems emerges. The
weaknesses in the Double Dribble project will be avoided by focussing
on influence from players in the same physical vicinity, while
emergent behavior, as exhibited in the CitiTag project, will be
encouraged by exploring multiple modes of gameplay. The Touch-Space
and Magic Land projects offer ego-centric visualizations that limit
the ability of multiple players to interact within a larger group
context. By addressing these considerations, as well as appropriating
the Human Factors found in other systems, a clear focus will emerge
for designing Mixed Reality games specifically for social gathering


Bardzell, Jeffrey.,
Bardzwell, Shaowen., Birchler, Craig., eds. 2007. Double Dribble:
Illusionism, Mixed Reality, and the Sports Fan Experience ACE ’07

Vogiazou, Yanna.,
Rajimakers, Bas., Geelhoed, Erik., eds. 8 June 2006. Design for
Emergence: Experiments with a Mixed Reality Urban Playground Game.
Personal and Ubiquitous Computing 11: 45-58

Cheok, David., Yang,
Xubo., Zhi Ying, Zhou., eds. 2002. Touch-Space: Mixed Reality game
Spaces Based on Ubiquitous, Tangible, and Social Computing. Personal
and Ubiquitous Computing 6: 430-442

Cheok, Adrian D., Teh,
Keng Soon., Duy Nguyen, eds. April 2006. Social and Physical
Interactive Paradigms for Mixed-Reality Entertainment ACM
Computers inEntertainment

Milgram, Paul 2006.
Some Human Factors Considerations for Designing Mixed Reality
Interfaces. Virtual Media for Military Applications KN1-1
– KN1-14

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