Augmented Reality is becoming widely available thanks to the widespread use of mobile devices
such as smartphones and tablets popular categories include lifestyle apps such as furniture placement
utility apps such as measuring tapes and educational apps such as celestial body
visualizers there are other types of AR besides mobile and researchers are currently exploring
new devices and new interaction techniques but rather than creating novel techniques
this work focuses on how to create interactive prototypes within the existing mobile design space
currently creating fully interactive prototypes requires coding an extensive programming skills
so we wonder how can designers prototype interactive AR without the need of coding well for
other interactive mediums such as websites or screen based mobile apps designers have a set of
rapid prototyping techniques at their disposal they use sketching to quickly illustrate ideas
for example on a whiteboard depicting different screens of a mobile application
sometimes they use paper prototyping maybe to get a representation closer to the final size
to support interactivity without programming they can use the Wizard of Oz technique
where one designer can play the role of the computer and finally all this work
can be recorded to illustrate a scenario or to explore multiple ideas with a technique called
video prototyping one drawback of these rapid techniques is that the output is
a non-interactive video the designer can only press play and watch it to create interactivity
these representations are used as guidelines for programmers to translate them into symbolic
representations generally using programming code here we want to support a workflow that allows
designers' representations to be reused so instead of being disposable guidelines
they will be essential parts of the interactive prototype okay so how can we do this for AR
first AR programming has a heavy use of realistic 3D models but we should also be able to work with
simple 2D sketches also to animate these objects designers need to define curves timings or even
detailed keyframe animations however designers can simply enact the animation with a gesture
in a similar way to the Wizard of Oz technique in contrast to traditional video prototyping
where the scenario is recorded at the end for AR we need to record the scenario at the beginning to
capture the spatial properties of the environment with all this in mind let's introduce Rapido
a tool that allows the creation of interactive AR prototypes using demonstrated examples let's try
to prototype an AR furniture app it looks simple but has many details that could be easily ignored
while prototyping only with 2D techniques Rapido supports three phases video prototyping,
programming with examples, and testing we start by capturing a video background in the scenario
we want to be able to place a lamp in different positions so we make sure to capture all those
angles in advance we can draw sketches to represent a catalog, a circular marker, or a lamp
the user should be able to select an item from the catalog in Rapido we can demonstrate user inputs
by pressing the record input button in this case we perform a tap gesture on top of the catalog
by default sketches are attached to the screen to represent menus or items but they should also be
able to pinned in the 3D world to pin the lamp to the user focus we create a link between the
pin action and a yellow focus square the focus square position is calculated as the intersection
between the closest plane and a ray casted orthogonally from the center of the screen
next the video shows the user moving the lamp to the table
to signify that the lamp's position is being edited we want a floating animation with Rapido
we can create animations by pressing the record animation button and drawing an
animation path with a finger the user should now be able to move the lamp from the floor
to the table by panning with a finger on the screen after performing the user's pan gesture
we see a red target appearing on the scene representing the corresponding world touch
the position of the world touch is calculated in a similar way to the position of the focus square
the only difference is that the starting point is the location of the finger on the screen
we will now move from the AR interface to the overview interface in this phase we turn the video
prototype into an interactive prototype we can see that every action that we created on the tablet is
shown in a timeline view like in a video editing application the timeline contains tracks for the
demonstrated user inputs and the corresponding actions designers' representations generally
work with visual states like a user flow depicted by screens of a mobile application this linear
representation use a concrete scenario however a computational state machine should be general
and cover not only this scenario but any other sequence of user inputs Rapido infers an initial
state machine from the linear states identified in the timeline at the top we can see that Rapido
assumes that every input generates a new state with six placeholders every action that is below
a placeholder will be added to the corresponding state in the diagram by default Rapido enumerates
the states but we can type-in more descriptive names for example selecting an item from the
catalog placing the lamp observing the selected results and finally repositioning the lamp
we can now test the interactive state machine on the tablet by pressing the test button during
testing the state machine diagram will highlight the current state and the current transition
to help debug the prototype in less than 10 minutes Rapido enabled us to create a video
prototype of a furniture placement application and turn it into a fully interactive AR prototype
for more details on Rapido read our paper you will find an analysis of the related work and a
discussion about its current limitations we just covered a small portion of what Rapido can do
and its opportunities to support many other types of AR devices to which extent
this approach could work for designers in their current practices will require further studies
but we hope to inspire other researchers to combine designer-friendly representations
with symbolic representations for the creation of interactive AR prototypes thank you