MeetAlive: Room-Scale Omni-Directional Display System
for Multi-User Content and Control Sharing
Andreas Rene Fender
Aarhus University
Aarhus, Denmark
andreasfender@cs.au.dk

Hrvoje Benko
Microsoft Research
Redmond, USA
benko@microsoft.coma)Andy Wilson
Microsoft Research
Redmond, USAawilson@microsoft.comb)Figure 1. MeetAlive transforms an ordinary meeting room into an omni-directional display for sharing content. (a) The walls arounda meeting table serve as a canvas for desktop content. (b) Participants of a meeting can share their desktop at any time anywhere in
the room. Our system keeps track of participants and content.
ABSTRACTACM Classification Keywords

MeetAlive combines multiple depth cameras and projectors
to create a room-scale omni-directional display surface
designed to support collaborative face-to-face groupmeetings. With MeetAlive, all participants may
simultaneously display and share content from their personal
laptop wirelessly anywhere in the room. MeetAlive gives
each participant complete control over displayed content in
the room. This is achieved by a perspective corrected mouse
cursor that transcends the boundary of the laptop screen to
position, resize, and edit their own and others’ sharedcontent. MeetAlive includes features to replicate content
views to ensure that all participants may see the actions ofother participants even as they are seated around aconference table. We report on observing six groups of threeparticipants who worked on a collaborative task withminimal assistance. Participants’ feedback highlighted thevalue of MeetAlive features for multi-user engagement inmeetings involving brainstorming and content creation.

H.5.2 [Information Interfaces and Presentation]: User
Interfaces – Graphical User Interfaces.

Author Keywords

Meeting system; Room scale; Collaboration; Large displays;
Projection Mapping
Permission to make digital or hard copies of all or part of this work forpersonal or classroom use is granted without fee provided that copies are
not made or distributed for profit or commercial advantage and that copies
bear this notice and the full citation on the first page. Copyrights forcomponents of this work owned by others than ACM must be honored.
Abstracting with credit is permitted. To copy otherwise, or republish, topost on servers or to redistribute to lists, requires prior specific permission
and/or a fee. Request permissions from Permissions@acm.org.
ISS '17, October 17–20, 2017, Brighton, United Kingdom© 2017 Association for Computing Machinery.
ACM ISBN 978-1-4503-4691-7/17/10…$15.00
https://doi.org/10.1145/3132272.3134117

INTRODUCTION

Face-to-face conference room meetings serve a variety of
purposes [20]: meeting new people, working through issues,reaching decisions, presenting projects, lectures, generatingideas and many more. In a typical meeting room, chairs arearranged around a large conference table so that participants
are facing each other (Figure 1a). This allows for effective
face-to-face communication during discussions.
Such meetings nowadays normally feature digital content(e.g., presentation slides) displayed on a wall for everyone tosee. Traditionally, participants physically connect theirlaptop to the display. In modern setups, content is transmitted
wirelessly [1]. Typically, only one person at a time is incharge for displaying and controlling content. Digital content
can only be displayed at one specific location (e.g., a display
in the room or a projection surface) potentially making it
difficult for all participants to see the display in a face-toface arrangement. Lastly, passing control of the single
display between participants remains a time-consuming
process, often disrupting the flow of a meeting.
In this paper, we present the MeetAlive system, designed toenable every participant in the meeting to display content
from their laptop at any time on any wall surface in the roomand control their own content and content of others
regardless of their role in the meeting.
MeetAlive enhances an ordinary meeting room with fiveprojectors covering the walls and table to create a tenmegapixel omni-directional room-scale display (Figure 1b).

Every participant in a MeetAlive conference room can sharethe desktop from their personal laptop and control a cursor
both on their screen and everywhere in the room. Eachparticipant controls the arrangement of their content and as
well as the content of others. Participants can freely move,resize and replicate content to ensure optimal visibility while
maintaining a face-to-face seating arrangement. Finally, allparticipants can directly edit any content displayed by any
participant.
The main contribution of our work is a novel system, wherea combination of existing technologies is utilized specificallyto enhance a meeting room scenario. To the best of ourknowledge, MeetAlive is the only conference room display
system that offers:••••

omni-directional multi-user room-scale display;where every participant can easily share, position, scale,edit, replicate and snapshot content from their laptops
anywhere on the room’s walls;
using a per-participant perspective-corrected mouse
cursor;without requiring the user to worry about which
projector they are controlling.

The interactive capabilities of MeetAlive are illustrated in
Figure 2. We also contribute feedback from our user
evaluation of MeetAlive with six groups of three participants(18 total) collaborating on a task. Participants reported that
MeetAlive was easy to learn and use and indicated higher
engagement, better control of content, and more awarenessduring the meeting compared to their typical meeting
experience.

The presenter displays thepresentation shared from theirlaptop at the center wallbehind them.

A participant in the back row
has a hard time seeing thebullet points at the bottom, sothey replicate the window anddisplay it in front of them.

The presenter reaches a slidewith an important diagram, sothey create a snapshot andposition it for later reference.

A participant in the audiencehas a question in the middle ofthe presentation. To clarify
what they are asking, theyquickly place an image fromtheir laptop on the wall andrefer to it (blue border).
Another participant has aquestion, but does not want tointerrupt, so they make asnapshot of the current slideand place it under the diagram
for later reference (green).

RELATED WORK

We focus our overview of related work on augmented
meeting room systems, multi display environments androom-scale projection displays. We restrict our review to colocated experiences.
Augmented Meeting Room Systems

Providing more effective collaborative meeting room
experiences has been an active research area for decades.
Notable early examples include Tivoli [22], based on
Xerox’s LiveBoard touch-enabled vertical display, andelectronic meeting systems by Nunamaker et al. [20] which
combined large shared and small personal displays.
More recently, many custom systems explored specific colocated collaborative activities such as work meetings [14,31], design tasks [12, 30], scientific inquiry [33], informal
meetings [9, 16, 17], and software development [3, 4]. For
example, WeSpace [33] was designed to support regularmeetings of scientists, incorporating an interactive tabletop
and a large high-resolution vertical display. Pictionnaire [12]and NiCE [9] focused on integrating physical and digitalassets in a seamless fashion to aid informal group meetings.
WeSearch [16] was designed for collaborative web searching
on a large tabletop display, finding that increased awarenessstimulates discussion among group members. inSpace [31]Havingconcludedthepresentation, the meetingtransitions to a more general
discussion. The speaker joins
the table and no longer
controls
themeeting.
Participants discuss various
topics while continuing toshare their desktops.

Figure 2. Possible meeting scenarios supported by MeetAlive.

and iRoom [14] focused on the custom design of meeting
spaces to foster collaboration. Office Social [7] provides
shared slide view and control mechanisms for the audience
members in a presentation scenario. Oblong Technologies’
Mezzanine [21] incorporates a variety of personal and shareddevices and displays into a unified meeting system.
Most previous room meeting systems feature a large,
dedicated shared display, requiring participants to orient
themselves for best view. Such configurations can limit theface-to-face interaction with other participants. In contrast,
the large shared display in MeetAlive envelops theparticipants in an omni-directional (potentially even
immersive) manner. This allows for more flexible

arrangement of content, higher overall resolution, as well as
the sharing, control and joint editing of content from any
meeting participant on any available surface in the room.
Multi Display Environments

Many research projects have explored combining multiple
heterogeneous displays to support meeting scenarios. Streitz
et al. presented i-LAND [29], a collection of collaborative
workspaces investigating creativity support in group work.
The Emmie system [6] used multiple displays with a variety
of form factors (including head-mounted displays) to create
a consistent collaborative environment where users canconnect their personal devices and view both 2D and 3D
spatialized data. In addition to meeting scenarios, Multidisplay environments have been explored in the context ofcollaborative programming [3], lunch table conversations[17], and scientific visualizations on high-resolution tiled
displays [1].
Nacenta et al.’s E-conic system [19] investigated the conceptof perspective-corrected multi-display environments. We
build on Nacenta et al.’s Perspective Cursor [18] whichallows for seamless movement between displays by taking
the user’s perspective into account.
Allowing multiple users to simultaneously control content ina multi-user multi-display environment has been explored ina variety of projects (e.g., [11, 12, 17, 21, 32, 33]). However,most systems restrict the joint control and editing to thecontent residing on the shared display and not on personal
devices. Inspiration for MeetAlive’s simultaneous editing
features came from Wallace et al. [32] who demonstrated
multiple users sharing parts of their desktop while allowing
for remote input in a many-to-many fashion.
Room-Scale Projection Displays

MeetAlive’s room-scale display is based on spatial
augmented reality technology [23], primarily based on
projection mapping. While we share much of the corefunctionalities and ideas with other room-scale projection
mapping systems (e.g., Office of the Future [24], Urp [30],
CAVE [8], LightSpace [34], Ubi Displays [10], and
RoomAlive [15]), we use projection mapping purely as anenabling technology for a seamless display on every surface
in the room, and focus our efforts on supporting sharing andediting of content among multiple participants in the room.
Conceptually, MeetAlive is closest to Rekimoto and Saitoh’s
Augmented Surfaces [25] where two projectors transformthe table and wall surfaces into a continuous display
supporting the exchange of documents between laptops. In
contrast, we focus on meeting scenarios and treat the shareddisplay as a room-scale display that supports joint editing
and control for increased awareness of actions andcollaborative work.
Guidelines and Surveys

Finally, we draw inspiration from Huang et al.’s “Secrets to
Success and Fatal Flaws” [13] which aggregates knowledge
and guidelines from a comparison across multiple systems

exploring collaboration on large displays. We further draw
our guidelines from other observational research [5, 26, 27]
that examines issues of awareness, social aspects, andproductivity in collaboration on large displays.
MEETALIVE DESIGN GOALS

MeetAlive is designed to support the different phases of ameeting and transitions between these (Figure 2). Many ofour design goals are tackling common problems in meetings
as also pointed out by related work. For instance, somemeetings suffer from an inequality of participation andcontribution of participants during discussions. Other
problems include the loss of eye-contact between
participants when looking at the digital content and potential
inconvenient postures when having to rotate the headtowards the display. While MeetAlive can facilitate theexisting one-person-in-charge dynamic typical of today’s
conference rooms, it can further support more egalitarian
scenarios, where multiple people can share their desktop, edit
each-others’ content, and contribute equally to theconversation in the room. Furthermore, we envision
MeetAlive to be used for collaborative tasks like
programming. Based on our vision described earlier anddrawing from guidelines from related work, we describe themain design goals of our system:
Equal control among participants: To maximize
participation and contribution of all participants, the systemshould give equal control to everyone in the meeting. Every
participant is always in full control, even during
presentations with one speaker. Because participants are colocated, and the system is designed so that all actions arevisible to all participants, we rely on the participants
themselves to negotiate potential conflicts that can arise withshared editing and control.
Simple and quick reconfiguration of environment:
Instead of optimizing for a specific meeting workflow, we
acknowledge and emphasize the dynamic nature ofmeetings; i.e., situations, roles and communication patterns
can change within a meeting. The system should provide afast and simple mechanism for participants to quickly
configure the environment according to the needs of themeeting.
Minimizing context switching: The participants should be
able to easily switch between working on their own laptop
and interacting with the content in the room.
Simple and familiar user interface: The interface should
be familiar, easy to learn and use for a wide variety of people
to avoid embarrassment from learning the system in a public
situation [5]. The interface and its use should not distractfrom the meeting itself.
Facilitate face-to-face arrangement: The system shouldmake it possible for the participants to maintain a face-toface arrangement while comfortably viewing and editing
projected content.

MEETALIVE INTERACTIVE CAPABILITIESIn this section, we describe the core features of MeetAlive.
Color coding users: To identify ownership of content andcursors, each participant and their laptop is assigned a uniquecolor when they connect to the MeetAlive system. A diffuse
colored area is displayed around each laptop on theconference room table in our room (Figure 3).
Desktop sharing: MeetAlive participants can share theirdesktop by pressing Ctrl+D. A live copy of their desktop

Figure 4. Cursors in MeetAlive. (1) Desktop Cursor is a virtual
copy of the standard OS cursor and it shows that the participant
is working within their own desktop. The cursor is flat. (2)Room Cursor is activated when the participant moves the
cursor out of their own desktop. It is rendered lifted. (3) The
participant can access room-related functionalities and arrange
content in the room with the room cursor and the title bar icons.

Figure 3. Example setup with four laptops. Each laptop is
assigned a unique color.

is then displayed on the wall directly in front of them.
Content window title bar: Every shared desktop is
displayed as a rectangular content area with a title bar (Figure4). The title bar contains a caption to indicate the type or stateof the content, and is colored to match the assigned color ofthe desktop’s owner. Participants can freely position content
by dragging its title bar. They can also resize each content
window by dragging the resize button. Lastly, they can close
any content window by pressing on a close button.
Depending on the type of content, the title bar also contains
buttons for replication and creating snapshots (discussed
below).
Desktop Cursor: Each participant controls one cursor
identified by the assigned color. The cursor is controlledusing the participant’s laptop touchpad or mouse, and has
two interactive states. The first state, which we call Desktop
Cursor, is the ordinary cursor when working within theparticipant’s laptop display; i.e., the default behavior of theoperating system cursor. The Desktop Cursor is rendered on
the participant’s laptop as well as on the shared content in theroom, where it appears as a flat cursor (cursor 1 in Figure 4).
Room Cursor: The second state, which we call Room
Cursor, is activated when the participant’s Desktop Cursor
reaches the edge of the laptop display (or, equivalently, when
the cursor reaches the edge of the projected window). The
cursor is rendered with a shadow to appear slightly above thesurface, indicating that it is now operating outside of theparticipant’s shared desktop (cursors 2 and 3 in Figure 4).

Each participant can control the shared elements in the room
via their Room Cursor. To accommodate varying
arrangement of people in the room, we use the relative
movement of each person’s positioning input device (e.g., amouse) together with 3D model of the environment and theperson’s point of view to determine the movement of the
RoomCursor in their perspective field of view. This behavior
closely resembles the Perspective Cursor technique [18]whereas we dynamically slow down cursor movement on
surfaces with narrow grazing angles to the user.
Remote input: By clicking the content window of anotherparticipant, remote desktop control is activated. Mouse
clicks and key input are then redirected to the laptop whichis sharing the respective content. Using this functionality,
participants can jointly edit content on each other’s
computers. Furthermore, participants can send the content of
their clipboard to the other machine and paste it by pressing
Alt+V.
Replication: In MeetAlive, it is easy to create multiple
instances of some shared content. The title bar of a content

Figure 5. Replication and Snapshot functionality: (a) The
participant clicked the replicate button. The replicated content
window is updating the same way as the original. (b) The
participant clicked the snapshot button, which takes an imageof the current state of the content window.

window contains buttons for creating replications (Figure5a). When the replication button is pressed, a new content
window is created with the same title bar. This content
window is updated in real time in the same way as theoriginal. The window can be positioned and resized without
affecting the original. Replication can be used to ensure thatevery participant can comfortably view the replicatedcontent, especially when they are sitting opposite to eachother. Cursors hovering over replicated content are renderedsemi-transparently in every replication.

MeetAlive client software runs on a variety of standard
laptops without the need for a dedicated graphics card. Our
MeetAlive room is equipped with a Wireless 802.11ac
access point as well as several wired network ports in thetable for easy network connectivity for each client.
System Architecture

The MeetAlive Server handles connections, event processing
and room rendering. Each participant can use their own PC
and the MeetAlive client software to connect to the
MeetAlive Server.

Snapshot: When pressing the snapshot button, a new content
window including title bar is generated and can be positioned
and resized freely (Figure 5b). The content shows a snapshotof the shared desktop from the moment the button waspressed. This window is not updated in real time and no
cursors are replicated. The Snapshot function enables quick
capture of content (e.g., during presentation) to enablefurther discussion or serve as a reminder for later.
MEETALIVE IMPLEMENTATION

We now describe the key infrastructure details enabling
MeetAlive features and discuss the system’s performance.
Hardware Setup

The MeetAlive room display employs five Optoma
EH415ST projectors. The resolution of each is 1920x1080
pixels for a combined total of about ten megapixels.
Projectors are arranged such that there is one projecting onto
each of the four walls of our meeting room and one
projecting on to the meeting room table (Figure 6).
Eight Kinect v2 cameras are installed in the ceiling. Each isconnected to an Intel NUC mini-PC computer (Intel Core i5,
8GM RAM) processing the camera streams, tracking eachparticipant’s body position in the room and transmitting alldata via Ethernet. The RoomAlive Toolkit Ensemble
Calibration 1 is used offline to calibrate the projectors andcameras, finding the pose of each.

Figure 7. A Unity Editor view of the MeetAlive Server runninga live meeting in the room. Each participant is represented as a
tracked skeleton and color-coded position at the table. The
shared desktop from the green participant can be seen on thewall. Projectors and Kinect cameras are shown near the ceiling.

Both MeetAlive client and server software are implemented
in Unity 3D game engine 2 (Figure 7). Furthermore, the open
source RoomAlive Toolkit for Unity plugin is used to
combine projector displays and Kinect skeletal tracking
streams to create a unified 3D spatial display similar to theroom-scale display in the RoomAlive project [15]. Oncecalibrated, all projectable areas are treated as a single display,
enabling the sharing of content without worrying about
which projector ultimately displays the content.
Each MeetAlive client captures the desktop contents of theirlocal display as well as mouse and keyboard events. This
information is streamed to the server as two separate streams(desktop and input). A native Unity plugin captures thedesktop on the MeetAlive Client using on the real-time
DirectX (DXGI) Desktop Duplication API. Desktop captures
are compressed with JPEG compression (quality set to 35%)
in order to reduce the network bandwidth requirement.

Figure 6. Floorplan of the MeetAlive room showing
approximate positions of five projectors in the ceiling (one perwall and one projecting down on the conference table). Right
image shows the installation of the five projectors in the ceiling.

The MeetAlive server runs on a custom PC capable ofdriving up to eight simultaneous displays (Intel Core i7, 32
GB RAM, two Nvidia GeForce GTX 980 graphics cards).
All five projectors are directly connected to our server.
1

https://github.com/Kinect/RoomAliveToolkit

The MeetAlive server receives the two streams from eachclient and updates the overall state of the room display. The
server distributes the input events to other clients to enable
collaborative editing across machines (similar to [32]).
System Performance

The performance of our system depends on a variety ofconditions such as network bandwidth, client display
resolution, image compression choice. We conducted a2

http://www.unity.com

series of tests to characterize the performance of our current
prototype system (five projectors and eight cameras).
We stress tested the streaming performance with up to six
clients simultaneously streaming their desktops (full HD
resolution 1920x1080). MeetAlive was able to maintain thesteady streaming framerate of ~10Hz for each client. With
smaller number of clients, the framerate can be higher, but
we chose to keep 10Hz as the default streaming framerate as
it provided a good tradeoff between the overall system
responsiveness and reasonable network bandwidth
utilization. Therefore, each MeetAlive client streaming fullHD desktop content at 10Hz using JPEG compression with a
35% quality setting requires approximately 16Mbps of
network bandwidth. When bandwidth is further limited,
MeetAlive clients automatically throttle the desktop imagetransmission framerate, without throttling transmission of
the comparatively tiny input event stream (mouse &keyboard events). With our network setup and chosenframerate, we experienced very few dropped frames during
operation (e.g., in our experiment, with four clients
streaming via wireless network for 15 minutes, our system
dropped ~0.5% of incoming frames due to longer than
expected transmission delay).
Furthermore, we measured the latency of the content
projected on the room display compared to the local screen.
When clients are connected via wired Ethernet connections,
we observed the following system latencies: one client~200ms, two clients ~230ms, three clients ~290ms, and fourclients ~340ms. Using the wireless network instead of thewired connection added additional 10-20ms to the measured
latency.
MeetAlive currently uses JPEG compression for desktop
image transmission. However, JPEG compression anddecompression is a fairly CPU intensive and long operation(~40ms combined). One future improvement to the
MeetAlive system latency and network bandwidth utilization
would be to use hardware accelerated compression (e.g.,
H.264 MPEG4) or compression methods that are specificallydesigned for remote desktop protocol (RDP).
USER EVALUATION

To explore the usability of MeetAlive and collect feedbackon the features and interactions it affords during meetings,
we conducted a user evaluation with 18 participants recruitedfrom our organization (six female, ages 25 to 52).
Participants were divided into six meeting sessions (groupsof three in each session). Each session lasted approximately
one hour. Participants received a $10 gift card for their time.
The main part of the user study was a collaborative
brainstorming task in which participants researched a given
topic to gather information. We used a collaborative searchtask similar to that of WeSearch [16], with an added goal tojointly create a presentation.
All participants were very familiar with typical businessmeetings in similarly-sized conference rooms in ourorganization. They confirmed that they have both been active
presenters and listeners/participants at similar meetings
before.
Apparatus

For the study, we pre-arranged four laptops in our MeetAlive
conference room as seen in Figure 3. The experimenter used
one laptop while the participants used the remaining threelaptops. The room consists of four walls: one wall in thecenter, two walls to the side including doors and one wallwith a large one-way mirror. While the mirror and the room
behind it are designed for observing the meetings without
interfering, the mirror prevented projection on much of therear wall. During the study, this wall could not be used forcontent placement.
Procedure

Each participant was greeted and asked to take a seat in frontof one of the provided laptops. The study was initiated withan experimenter giving a 10-minute how-to tutorial on themain capabilities of the MeetAlive system. In the beginning,tutorial presentation slides were displayed on a single
window on the center wall. However, as the presentation
progressed, the experimenter directly demonstrated eachfeature of MeetAlive in the room. During the presentation,
participants were also asked to try each feature immediately
after it was introduced. This includes sharing their own
desktop, moving the window, resizing it, creating replicatedwindows and creating snapshots. At the end of this tutorial,
all participants were familiar with the core features of
MeetAlive.
Following this tutorial, participants were given 30 minutes tocreate a short presentation (approximately five slides) on a
specific topic: “What is the difference between cloud, fog
and mist?”. Participants could choose any workflow or
strategy they wanted, could access the Internet, and were free
to arrange the content around the room however they wanted,
i.e., they could choose anything from a conventional setup
with one connected laptop to arrangements that fill the wallswith shared content from every laptop. The experimenter
was present in the room during this task to answer technicalquestions, but did not otherwise participate in the task. Aftercompleting the task, each participant completed a survey
consisting of ratings and qualitative feedback. All ratings
were based on a 7-point Likert scale.
Results

While each group had a slightly different assignment of roles
and workflow they all successfully created a simple
presentation.
The survey specifically asked participants about theirawareness of projected content in the room, how easy it wasfor them to control and arrange content, and their thoughts
about the overall workflow. This section provides anddiscusses some survey findings.

AwarenessWe asked participants about how they perceived the content
surrounding them:strongly disagreestrongly agree

Being able to position a cursor and content over any wall areain the room was well appreciated, but it also required that theparticipant remembers where they left the cursor upon lastaction. Luckily, due to the perspective nature of the Room
Cursor, by moving the cursor via mouse or touchpad, theparticipant was able to quickly notice where the cursor is in
the room.
Workflow

We asked participants questions about the system’s impact
on workflow and group dynamics:
strongly disagreestrongly agree

Participants quickly understood the arrangement of content.
They did not report any confusion about replicated content at
the walls in front of them or behind them. Figure 8 shows atypical arrangement as well as different situations.
Control

One part of our questionnaire investigated the ease of use interms of moving cursors, positioning content, etc. Survey
results suggest that participants had little trouble controllingthe system and arranging content:strongly disagreestrongly agree

Participants were responsible for arranging all content whensolving the task. This also includes resolving occlusion byother participants while positioning the window, which was
generally not considered demanding. Locating the Room
Cursor outside the desktop on the other hand was sometimes
challenging, which is reflected in the participants’ scores.

b)

In the observed meetings, all participants got used to thesystem quite easily. Even after only a short training period,
participants made use of most of the system’s features
unprompted to optimize their workflow. We have observed
them arranging and replicating content to work effectively
on the task with very few interruptions. We also observed theparticipants helping each other with features that someone
forgot, or frequently reminding each other to use a particularfunctionality to make better use of the system.
In addition, we observed that the meetings typically had two
distinct phases. In the first phase, the participants discussed
the task, assigned roles amongst themselves and spent time
configuring the content and the windows around the room.
During this phase, the room arrangement changed a lot andthere was a lot of discussion on what should go where. The
second phase consisted of the search for content and joint
editing of the presentation and during this time thearrangement of the room was mostly stable with only
sporadic movement of the content for better visibility. Thissuggests that it is likely that most meetings in MeetAlive
would converge on an agreeable arrangement and only
modify it when a different task is presented to theparticipants. An interesting extension of our system would
be to consider offering a few preset layouts for content
around the room as an easy way to arrange a room for ameeting.
Overall Impressionsd)Figure 8. Arrangements of content by participants during theuser study and the most frequently used arrangement (lowerright). Groups tended to place the desktop with the working
version of the presentation on the center wall and the otherdesktops and replications, which were mainly used for web
search, at the side walls.

We asked the participants about their impressions of using
the MeetAlive system in contrast to their existing meetingroom experiences. Participants were overwhelmingly
positive in their feedback and expressed interest to use
MeetAlive in their everyday meetings. Interestingly, few
participants commented that using the MeetAlive system
made them feel a lot more invested and more engaged in themeeting. For example, one participant stated the following
about working with the system:
Overall, once you get used to all the cursors andthe experience of owning your own window, it's
really fun to collaborate this way. I found myself
being much more engaged socially than I
normally would.
Participants also voiced some negatives about the system;
namely that there is a learning curve required to effectively
use all the functionality of the system and that keeping trackof multiple simultaneous cursors can be a bit overwhelming.
However, many offered praise of the main idea of everyonein the meeting being able to equally contribute, control andshare. For example, one participant commented:
The notion of leaving the traditional bounded boxof a TV, monitor, or projector wall and be able todisplay content anywhere is awesome. I
particularly enjoyed and liked some of the sharing
and control responsibility semantics, such as theability to duplicate my screen behind me and thenthe people who can see that duplicate version
controlling it for themselves.
DISCUSSION AND FUTURE WORK

Our final system is reduced to the core functionalities needed
to enable participants to easily share and manipulate content
anywhere in the room. It mixes familiar practices andinteraction techniques with spatialization of content. In thefollowing, we discuss features of MeetAlive that go beyond
these core functionalities and yield potential future work.
Equal access and control of all content in the room is one of
the core design goals of MeetAlive. We observed in ourstudies that participants heavily relied on social protocols toeffectively negotiate the control of content (e.g., saying out
loud “I am editing now”). We did not observe many conflicts
with participants simultaneously arranging content in theroom. However, concurrent editing or manipulation of theshared content was sometimes confusing for participants andshould therefore be further investigated in the future.
Our vision of MeetAlive is to support the dynamics ofmeetings under a variety of situations. While our current
evaluation was mainly focused on usability aspects, future
longer-term deployment studies should give us insights on
how MeetAlive impacts meetings, its versatility, and what
new behaviors and communication patterns emerge among
its users.
To allow MeetAlive novices to quickly become proficient atusing the system, MeetAlive interfaces are deliberately
designed to closely resemble those of familiar WIMP
systems. This enabled a smooth transition from the laptop to
the room. For example, with the same mouse movement,
participants can go from their own desktop to the title bar ofanother participant’s shared view to manipulate it. There isno need to switch between interaction techniques. However,
WIMP metaphors also impose substantial visual overhead tothe content and the interactions. On-demand or contextsensitive menus or interfaces may reduce the need forcontinuous on-screen user interface elements.
We implemented a gestural hand pointing technique for
placing and moving content around the room similar to [4].
Using that interaction, a person could position content byselecting a window on their desktop and pointing to the wallat the same time using their finger. However, this approach
suffered from poor pointing accuracy due to relatively noisy
skeletal tracking from the overhead cameras. Therefore, we
omitted this feature from the final system. More accurate
hand tracking capabilities might provide opportunities forfurther investigation of such interactions in meetings.
MeetAlive is implemented on top of the open source
RoomAlive for Unity framework which can support many
configurations of projectors and cameras. We have only
experimented with our setup of five projectors; however, it
would be interesting to explore how our system scales todifferent meeting rooms and configurations. Furthermore,
we’d like to explore meetings with more than four
participants. New challenges are introduced when having tonegotiate physical space for projecting content due to many
shared desktops. We experimented with simple grid-based
automatic layout adjustments, but we removed that feature
eventually, since it was not necessary for the number ofparticipants we had. Future iterations may investigate theimplications of many participants with a focus on different
approaches for automatic layouts.
Lastly, MeetAlive currently uses the table only for projecting
colored regions that indicate ownership of like-coloredcontent. During development, we implemented rotating
horizontal desktop views for the table surface. However, weremoved this feature in the final system. The rationale for theremoval is that the windowing system of many operating
systems and 2D UIs are designed to be viewed on a verticalscreen and not optimized for horizontal large displays. In
particular, every element on a 2D UI assumes the same
physical distance to the user’s viewpoint. Rectangular
content gets heavily distorted or needs a lot of space when
getting undistorted – especially since we assume thatparticipants are mostly sitting during meetings. Since wecannot adapt the inner contents itself, we chose to simply
keep the familiar vertical nature of desktop content by only
allowing to display content on the walls. Furthermore, as
opposed to walls, the table is often reserved for physicalobjects, sketches etc. We did not observe confusion in thatregard during our user study. Future iterations, however, canbuild upon the research on collaborative table top
interactions [16] to enable the more effective use of thetabletop in MeetAlive.
CONCLUSION

MeetAlive is an omni-directional room scale display systemdesigned for supporting face-to-face meetings. We integratestate of the art tracking and projection technologies into one
coherent system to enable participants to share content
anywhere in the room at any time during a meeting. Our
system is designed to work with and improve the dynamics
of meetings by providing equal control to every participant.
Furthermore, MeetAlive addresses the largely differing gaze
directions of participants by replicating content to ensure
visibility, so that participants can maintain eye contact andview content at the same time.
While this system is still a research prototype, it is alreadydeployed in our organization. Our preliminary feedback fromthe user study shows that it has the potential to positively
change the meeting experience. Overall, the results of our
first evaluation make us confident that MeetAlive performs
very well in meeting situations, is easy to learn and use, andintegrates well into the existing workflow of meetings. We
hope that MeetAlive can inspire a new model for conference
rooms where anyone can contribute, share, manipulate andedit content displayed around the room.
REFERENCES

1.
2.

3.

4.

5.

6.

7.

Apple Inc. 2017. Apple TV. Retrieved Aug. 24, 2017from https://support.apple.com/en-us/HT202618
Beaudouin-Lafon, M. (2011, October). Lessons learned
from the WILD room, a multisurface interactive
environment. In Proceedings of the 23rd Conference onl'Interaction Homme-Machine (p. 18). ACM.
DOI: http://dx.doi.org/10.1145/2044354.2044376.
Biehl, J.T., Baker, W.T., Bailey, B.P., Tan, D.S., Inkpen,
K.M., & Czerwinski, M. 2008. Impromptu: a newinteraction framework for supporting collaboration in
multiple display environments and its field evaluation
for co-located software development. In Proceedings of
the SIGCHI Conference on Human Factors in
Computing Systems (CHI '08). ACM, New York, NY,USA,
939-948.
DOI: http://dx.doi.org/10.1145/1357054.1357200.
Bragdon, A., DeLine, R., Hinckley, K. and Morris,
M.R., 2011, November. Code space: touch+ air gesturehybrid interactions for supporting developer meetings.
In Proceedings of the ACM International Conference on
Interactive Tabletops and Surfaces (pp. 212-221).
ACM.
Brignull, H., & Rogers, Y. 2003. Enticing people tointeract with large public displays in public spaces. In
Proceedings of INTERACT ’03. IFIP, 17-24.
Butz, A., Höllerer, T., Feiner, S., MacIntyre, B., &Beshers, C., 1999. Enveloping Users and Computers in
a Collaborative 3D Augmented Reality. In Proceedingsof the 2nd IEEE and ACM International Workshop on
Augmented Reality (IWAR '99). IEEE Computer
Society, Washington, DC, USA, 35-41.
Chattopadhyay, D., O'Hara, K., Rintel, S. and Rädle, R.,
2016, May. Office Social: Presentation Interactivity for
Nearby Devices. In Proceedings of the 2016 CHI
Conference on Human Factors in Computing Systems(pp. 2487-2491). ACM.

8.

Cruz-Neira, C., Sandin, D.J., & DeFanti, T.A. 1993.
Surround-screen projection-based virtual reality: thedesign and implementation of the CAVE. In
Proceedings of the 20th annual conference on Computer
graphics and interactive techniques (SIGGRAPH '93).
ACM,
New
York,
NY,
USA,
135-142.
DOI: http://dx.doi.org/10.1145/166117.166134.
9. Haller, M., Leitner, J., Seifried, T., Wallace, J.R., Scott,S.D., Richter, C., Brandl, P., Gokcezade, A., & Hunter,
S. 2010. The NiCE Discussion Room: Integrating Paper
and Digital Media to Support Co-Located Group
Meetings. In Proceedings of the SIGCHI Conference on
Human Factors in Computing Systems (CHI '10). ACM,
New
York,
NY,
USA,
609-618.
DOI: http://dx.doi.org/10.1145/1753326.1753418.
10. Hardy, J., Ellis, C., Alexander, J., & Davies, N. (2013,
June). Ubi displays: A toolkit for the rapid creation ofinteractive projected displays. In The International
Symposium on Pervasive Displays.
11. Hartmann, B., Beaudouin-Lafon, M., & Mackay, W.E.
2013. HydraScope: creating multi-surface metaapplications through view synchronization and input
multiplexing. In Proceedings of the 2nd ACM
International Symposium on Pervasive Displays(PerDis '13). ACM, New York, NY, USA, 43-48.
DOI: http://dx.doi.org/10.1145/2491568.2491578.
12. Hartmann, B., Morris, M.R., Benko, H., & Wilson, A.D.
2010. Pictionaire: supporting collaborative design workby integrating physical and digital artifacts. In
Proceedings of the 2010 ACM conference on Computer
supported cooperative work (CSCW '10). ACM, New
York,
NY,
USA,
421-424.
DOI: http://dx.doi.org/10.1145/1718918.1718989.
13. Huang, E.M., Mynatt, E.D., Russell, D.M., & Sue, A.E.
2006. Secrets to Success and Fatal Flaws: The Design ofLarge-Display Groupware. IEEE Computer Graphics
and Applications. 26, 1 (January 2006), 37-45.
DOI: http://dx.doi.org/10.1109/MCG.2006.21.
14. Johanson, B., Fox, A., & Winograd, T. 2002. The
Interactive Workspaces Project: Experiences with
Ubiquitous Computing Rooms. IEEE Pervasive
Computing1,
2(April2002),
67-74.
DOI: http://dx.doi.org/10.1109/MPRV.2002.1012339.
15. Jones, B., Sodhi, R., Murdock, M., Mehra, R., Benko,
H., Wilson, A.D, Ofek, E., MacIntyre, B., Raghuvanshi,N., & Shapira, L. 2014. RoomAlive: magicalexperiences enabled by scalable, adaptive projectorcamera units. In Proceedings of the 27th annual ACM
symposium on User interface software and technology(UIST '14). ACM, New York, NY, USA, 637-644.
DOI: http://dx.acm.org/10.1145/2642918.2647383.
16. Morris, M.R., Lombardo, J., & Wigdor, D. 2010.
WeSearch: supporting collaborative search andsensemaking on a tabletop display. In Proceedings of the2010 ACM conference on Computer supported
cooperative work (CSCW '10). ACM, New York, NY,

USA,
401-410.
DOI: http://dx.doi.org/10.1145/1718918.1718987.
17. Nacenta, M.A., Jakobsen, M.R., Dautriche, R., Hinrichs,
U., Dörk, M., Haber, J., & Carpendale, S. 2012. The
LunchTable: a multi-user, multi-display system for
information sharing in casual group interactions. In
Proceedings of the 2012 International Symposium on
Pervasive Displays (PerDis '12). ACM, New York, NY,
USA,
Article18,
6pages.
DOI: http://dx.doi.org/10.1145/2307798.2307816.
18. Nacenta, M.A., Sallam, S., Champoux, B.,
Subramanian, S., & Gutwin, C. 2006. Perspective
cursor: perspective-based interaction for multi-display
environments. In Proceedings of the SIGCHI
Conference on Human Factors in Computing Systems(CHI '06). ACM, New York, NY, USA, 289-298.
DOI: http://dx.doi.org/10.1145/1124772.1124817.
19. Nacenta, M.A., Sakurai, S., Yamaguchi, T., Miki, Y.,
Itoh, Y., Kitamura, Y., Subramanian, S., & Gutwin, C.
2007. E-conic: a perspective-aware interface for multidisplay environments. In Proceedings of the 20th annual
ACM symposium on User interface software andtechnology (UIST '07). ACM, New York, NY, USA,279-288.
DOI: http://dx.doi.org/10.1145/1294211.1294260.
20. Nunamaker, J.F., Dennis, A.R., Valacich, J.S., Vogel,D., & George, J.F. 1991. Electronic meeting systems.
Communications of the ACM 34, 7 (July 1991), 40-61.
DOI: http://dx.doi.org/10.1145/105783.105793.
21. Oblong Industries. 2016. Mezzanine. Retrieved Sept.
12,
2016
from:
http://www.oblong.com/mezzanine/overview/.
22. Pedersen, E.R., McCall, K., Moran, T.P., & Halasz, F.G.
1993. Tivoli: an electronic whiteboard for informal
workgroup meetings. In Proceedings of the INTERACT'93 and CHI '93 Conference on Human Factors in
Computing Systems (CHI '93). ACM, New York, NY,USA,
391-398.
DOI: http://dx.doi.org/10.1145/169059.169309.
23. Raskar, R., Welch, G., & Fuchs, H. 1998. Spatiallyaugmented reality. First IEEE Workshop on Augmented
Reality (IWAR’98).
24. Raskar, R., Welch, G., Cutts, M., Lake, A., Stesin, L., &Fuchs, H. 1998. The office of the future: a unified
approach to image-based modeling and spatiallyimmersive displays. In Proceedings of the 25th annual
conference on Computer graphics and interactive
techniques (SIGGRAPH '98). ACM, New York, NY,USA,
179-188.
DOI: http://dx.doi.org/10.1145/280814.280861.
25. Rekimoto, J. & Saitoh, M. 1999. Augmented surfaces: aspatially continuous work space for hybrid computing
environments. In Proceedings of the SIGCHI conferenceon Human Factors in Computing Systems (CHI '99).
ACM,
New
York,
NY,
USA,
378-385.
DOI: http://dx.doi.org/10.1145/302979.303113.

26. Russell, D.M., Drews, C., & Sue, A. 2002. Social
Aspects of Using Large Public Interactive Displays for
Collaboration. In Proceedings of the 4th international
conference on Ubiquitous Computing (UbiComp '02).
Springer-Verlag, London, UK, UK, 229-236.
27. Stefik, M., Foster, G., Bobrow, D.G., Kahn, K.,
Lanning, S., & Suchman, L. 1987. Beyond the
chalkboard: computer support for collaboration andproblem solving in meetings. Communications of the
ACM
30,
1
(January1987),
32-47.
DOI: http://doi.acm.org/10.1145/7885.7887.
28. Stoakley, R., Conway, M.J., & Pausch, R. 1995. Virtual
reality on a WIM: interactive worlds in miniature. In
Proceedings of the SIGCHI Conference on Human
Factors in Computing Systems (CHI '95), ACM, New
York,
NY,
USA,
265-272.
DOI: http://dx.doi.org/10.1145/223904.223938.
29. Streitz, N.A., Geißler, J., Holmer, T., Konomi, S.,
Müller-Tomfelde, C., Reischl, W., Rexroth, P., Seitz, P.,& Steinmetz, R. 1999. i-LAND: an interactive landscapefor creativity and innovation. In Proceedings of the
SIGCHI conference on Human Factors in Computing
Systems (CHI '99). ACM, New York, NY, USA, 120127. DOI: http://dx.doi.org/10.1145/302979.303010.
30. Underkoffler, J., & Ishii, H. 1999. Urp: a luminoustangible workbench for urban planning and design. In
Proceedings of the SIGCHI conference on Human
Factors in Computing Systems (CHI '99). ACM, New
York,
NY,
USA,
386-393.
DOI: http://dx.doi.org/10.1145/302979.303114.
31. Voida, S., McKeon, M., Le Dantec, C., Forslund, C.,
Verma, P., McMillan, B., Bunde-Pedersen, J., Edwards,
K., Mynatt, E.D., & Mazalek, A. 2008. inSpace: CoDesigning the Physical and Digital Environment to
Support Workplace Collaboration. GVU Center
Technical Reports #535. Georgia Institute ofTechnology.
32. Wallace, G. & Li, K. 2007 Virtually Shared Displays
and User Input Devices. USENIX Annual TechnicalConference.
33. Wigdor, D., Jiang, H., Forlines, C., Borkin, M., & Shen,
C. 2009. WeSpace: the design development anddeployment of a walk-up and share multi-surface visualcollaboration system. In Proceedings of the SIGCHI
Conference on Human Factors in Computing Systems(CHI '09). ACM, New York, NY, USA, 1237-1246.
DOI: http://dx.doi.org/10.1145/1518701.1518886.
34. Wilson, A.D., & Benko, H. 2010. Combining multiple
depth cameras and projectors for interactions on, aboveand between surfaces. In Proceedings of the 23nd
annual ACM symposium on User interface software andtechnology (UIST '10). ACM, New York, NY, USA,273-282.
DOI: http://dx.doi.org/10.1145/1866029.1866073.