A Study of Transitional Virtual Environments

Abstract

Due to real world physical constraints (e.g. walls), experimenting a virtual reality phenomenon implies transitional issues from one virtual environment (VE) to another. This paper proposes an experiment which studies the relevance of smooth and imperceptible transitions from a familiar and pleasurable virtual environment to a similar workplace as a mean to avoid traumatic experiences in VR for trainees. Specifically, the hereby work assumes that the user consciousness regarding virtual environment transitions is a relevant indicator of positive user experience during those. Furthermore, serious games taking place in purely virtual environments have the advantage of coping with various workplace configurations and tasks that the trainee can practice. However, the virtual world of serious games should be carefully designed in order to avoid traumatic experiences for trainees. The results presented stem from an empirical evaluation of user experience conducted with 80 volunteers. This evaluation shows that more than one-third of the participants did not even notice the VE global change.

Full text

A Study of Transitional Virtual Environments
Maria Sisto1(B
), Nicolas Wenk1, Nabil Ouerhani2, and St´ephane Gobron1
1Image Processing and Computer Graphics Group, HE-Arc, HES-SO,
Neuchˆatel, Switzerland
{maria.sisto,stephane.gobron}@he-arc.ch
2Interaction Technology Group, HE-Arc, HES-SO, Neuchˆatel, Switzerland
Abstract. Due to real world physical constraints (e.g. walls), experi-
menting a virtual reality phenomenon implies transitional issues from one
virtual environment (VE) to another. This paper proposes an experiment
which studies the relevance of smooth and imperceptible transitions from
a familiar and pleasurable virtual environment to a similar workplace as
a mean to avoid traumatic experiences in VR for trainees. Specifically,
the hereby work assumes that the user consciousness regarding virtual
environment transitions is a relevant indicator of positive user experience
during those. Furthermore, serious games taking place in purely virtual
environments have the advantage of coping with various workplace con-
figurations and tasks that the trainee can practice. However, the virtual
world of serious games should be carefully designed in order to avoid
traumatic experiences for trainees. The results presented stem from an
empirical evaluation of user experience conducted with 80 volunteers.
This evaluation shows that more than one-third of the participants did
not even notice the VE global change.
Keywords: Virtual reality ·Virtual environment ·Head-mounted dis-
play ·Health application ·Musculoskeletal disorder
1 Introduction
The effect of transitions between real and virtual environment (see Fig. 1)isa
subject that emerged with the renew of VR those last years. This section presents
the context of this work and the reasons we needed to understand better the
impact of word transitions on users.
1.1 Context
This project is a preliminary work for the project Serious Game for Health at
Work oriented towards prevention of Musculoskeletal Disorder (MSD) that aims
to reduce the MSDs occurrences in manufacturing industries. As a reminder,
MSDs are lesions to muscles, articulations or nervous systems due to repetitive
c
Springer International Publishing AG 2017
L.T. De Paolis et al. (Eds.): AVR 2017, Part I, LNCS 10324, pp. 35–49, 2017.
DOI: 10.1007/978-3-319-60922-5 3

36 M. Sisto et al.
Fig. 1. Context of the main question of this paper: how did the user consciously realize
virtual environment transition? [1].
work in an inappropriate position. According to the INRS [2], this is one of the
main work-related injuries in western countries, with costs of hundred of billions
of euros per year in Europe [3]. The idea is to create a Serious Game (SG) using
Virtual Reality (VR) that tracks players’ gestures and gives feedback whenever
a movement is potentially harmful (see Fig. 2). It has been shown that SGs
using VR are a valid solution in the health field as the main trigger for users’
motivation [4–6]. Furthermore, VR can be used to teach procedure sequences [7]
and movement tracking devices enables ergonomic monitoring [8,9]. Considering
previously described context relative to VR and the fact that SG development
must include various environments, we must evaluate potential impact of virtual
environment (VE) transitions on users. Results of the current study will therefore
help us tweaking the VE parameters in order to change and improve the exercise
context.
1.2 Literature Review
The SG domain being very specific, projects treating the same subjects are rare.
Many SGs and exergames are about health and re-education domains [10] but
very few cover the subject of MSD or movements and postures. We can cite
three of them. The first one is an application called “Halte aux TMS” by the
company daesign [11]. It is a web application explaining MSD dangers with
interactive videos and scenes. The second one is a study named “A Serious
Game to Improve Posture and Spinal Health While Having Fun” [12]. This
game is in two phases: one passive and one active. In the first phase, the user
has to correct the positions of a character portrayed working in a scene. In the
second phase, the user has to stand and do stretching exercises in front of the
Kinect. The application validates the exercise using the Kinect data. The third
one named “Kinect-Based Virtual Game for the Elderly that Detects Incorrect
Body Postures in Real Time” [13] has two aims. Firstly it helps the elderly to

A Study of Transitional Virtual Environments 37
Fig. 2. General idea: the user (right side) is immersed in VR and performs a manu-
facturing task (left side). A feedback is given about the potential dangers on the user
body (white figure on the right).
maintain physical activity and sense of balance. Secondly, it uses the Kinect
to give feedback on the dangerous postures. It also gives advice on the best
postures to avoid harm or falls. The game is in VR and the user has to catch
falling objects from the sky.
1.3 Environments and Transitions
The physical environment is an essential component, both in the working con-
text and in knowledge acquisition. We know, for instance, that the classrooms
organization impacts the student learning rate. For example, it has been shown
that factors such as environmental color, personalization and light have a signifi-
cant influence on this rate [14]. It has also been shown that factors such as light,
noise and room layout impact the well-being of employees [15,16] and hence
their productivity [17].
In order to enable optimal learning, the user should be placed in the best-
suited environment for this activity. The ART theory (Attention Restoration
Theory) [18] suggests that natural environments (whether immersion in nature
or observation of nature images or videos) stimulate the concentration recovery
ability and allows to be more relaxed. Therefore, we decided to put the user in a
virtual environment representing a “calm” scene in the middle of nature. More-
over, choosing a totally different environment from the usual one contributes to
motivating the user to play the SG. Actually, if the user is only placed in his
work environment, it is difficult to see the VR interest. In addition, the stress
linked to his being in his workplace may slow down the user’s learning rate.
Once the bad habits are banned from the exercises in a calm environment,
it must be ensured that those habits remain present in the workplace. In order

38 M. Sisto et al.
to do this, the user is gradually transposed to a virtual environment represent-
ing his actual work environment, relative to his progression in the game: the
environment will begin to change only when the user is able to correctly per-
form the required task. Thereby, the user will gradually become accustomed to
a more and more realistic environment and eventually translate the good habits
acquired through the calm environment to his work environment successfully.
1.4 Environment and MSDs
Although this is not the sole cause of MSDs, the environment is not entirely
foreign to these problems. Indeed, a noisy environment, fast work pace and
repetitive tasks take part in inducing stress to employees. Referring to the INRS
website: “There are many stress effects related to MSDs. Clamping and support-
ing forces are increased, muscle tension increases, recovery time increases. Stress
amplifies the pain perception and makes employees more sensitive to MSDs risk
factors.” [19].
1.5 Types of Environments
Keeping in mind the stress influence on MSDs, we can distinguish two environ-
ment types: the calm environment, which is the starting environment, and the
working environment, which is the environment towards which the transition
is heading. In order to allow a gradual evolution, a third type of environment
has been defined: the intermediate environment, which must be between total
decontextualization and the exact workplace reproduction. Several environments
of each type can exist, allowing customization according to user preferences and
actual working conditions. Thus, each personal session can be adapted according
to the needs with a corresponding combination of possibilities (see Figs. 3and 4
for an application example).
1.6 Technological Choices
For the development of 3D environments, the Unity Game Engine [20] has been
chosen because it allows the rapid creation of a scene from 3D objects and it
provides an efficient scripting system. Many resources are available on the Unity
Asset Store [21] and the community is substantial and very active. We have
chosen Blender [22] to edit 3D models because it is open source and gives us
the flexibility to import and export from and to multiple formats. The selected
HMD was the HTC Vive [23] because it provides a several-meters-wide tracking
zone which lets the player move physically into the virtual world while walking.
In addition, two special controllers (one for each hand) are provided to allow
a much more natural interaction than with a conventional keyboard or game
controller.

A Study of Transitional Virtual Environments 39
Fig. 3. Transitional concepts, three types of VEs are represented from left to right:
calm VE (see Fig. 5), intermediate VE (see Fig. 6), and work VE. (see Fig. 7). Figure 4
illustrates the transition’s impact can be on VEs.
Fig. 4. Main context transitions, from calm to workplaces.
2 Virtual Environment and Transitions
This section describes the chosen environments and their implementation. It also
describes the chosen types of transitions, with one example for each type.
2.1 Virtual Environment
Three calm environments have been designed: a garden, a beach and a snowy
mountain (see Fig. 5). The intermediate environment and the working environ-
ment are a living room and a watchmaker workshop.
The garden is a grassy place with trees and is very sunny. A tree and a sun
umbrella are near, providing some shadow. The sound of the wind and birds
can be heard in the background. The beach is sandy, has palm trees and is also
very sunny. Some very large beach umbrellas shade you from the sun. The sea
is calm, we can hear waves and a light wind blowing. We can also hear a seagull
shrieking. The mountain is snowy, with some pine trees. Little noise, just a light
wind and noises from small animals can be heard. The same round wooden table
has been used in the three scenes.
The intermediate environment is a living room. It is a closed space with
a large window on the quiet outside landscape, according to the EV that was

40 M. Sisto et al.
Fig. 5. Set of three calm VEs.
chosen in the beginning (in Fig. 6the calm scene is the garden). Faint sounds
from the outside can be heard.
Fig. 6. A living room: the intermediate VE.
The watchmaker workshop is a closed space, filled with workbenches and
tools. Large lateral windows let the natural light enter and thus the user can see
outside (see Fig. 7). Sounds from outside are no longer audible, but for work-
related sounds.
2.2 Transitions
The first environment is always calm, natural, outdoors. In order to make the
transitions more subtle, the intermediate scene (the living room) is indoors, but
still a calm environment. A living room is familiar to everyone and is a relaxing
place. A link with the calm environment is maintained by a large window show-
ing the outside and letting the faint sound from the outside world in. Once the
transition to the intermediate environment is complete, the change to the work-
ing environment is launched. The outdoor is still visible through the windows,
but without the sounds of nature and with the specific sounds of the workplace.
We can see this transitions in Fig. 4.
We have used different methods to change the scenes: fade in and out,
scale and position change, shape and texture morphing, offscreen appear-
ance/disappearance, fragmentation, sound transition.

A Study of Transitional Virtual Environments 41
Fig. 7. A workshop: the working VE. – i.e. potentially more stressful.
Fade In/Out — The fade effect is easily achieved by changing the alpha chan-
nel in the object shader. We have used it on the ground to make the floor of
the intermediate and work scene appear. The sound effects are also fades. The
sound’s volume slowly changes in order to make the sounds audible/inaudible.
Scale Change — The change of scale is a linear enlargement or shrinking on
a given time. This transition can be very subtle if applied to small objects, or
totally obvious on big objects. This effect has been used on the grass in the
garden scene and on the walls of both intermediate and work scenes. It can
create an illusion of movement, hence provoking motion sickness to sensitive
users.
Position Change — The change of position is a linear movement in a given
time period. We have used it on the tree in the garden scene and the pine in
the mountain scene. The trees back slowly away from the user (see Fig. 8). If
noticed, this transition has caused slight discomfort.
Fig. 8. Tree transition: the depicted tree virtually gets out of the scene not too fast,
and not too slowly, nevertheless only few subjects noticed such an odd behavior for a
tree.
Morphing — The morphing is the change of size and/or texture of an object.
Shape morphing cannot be done natively in Unity, so we chose Blender and its
KeyShapes in order to store both start and target vertex positions and import

42 M. Sisto et al.
them to Unity. On import, a Unity script is generated with the necessary options
to make a seamless shape transition. Texture transition has been done with a
custom shader by displaying a certain amount of two textures blended together.
In Fig. 9we can see the table shape and texture transition.
Fig. 9. Table transition: the table changes size and shape from round to rectangular
and texture from dark wood to white marble. The morphing is progressive, done in
a few minutes. This transition was under detected compared to our expectations (as
described in Sect. 4).
Offscreen Appearance/Disappearance — In an offscreen appearance/
disappearance, an object instantly appears/disappears when it is outside the
user’s field of view.
Fragmentation — Fragmentation is an effect created by the breaking of an
object into small pieces. This operation is not available natively in Unity, so we
used Blender in order to create the pieces. We applied it on the chairs in the
garden, where we wanted to apply a blow out effect (see Fig. 10). Unity provides
an explosion option that generates a force applied on each object in an epicenter.
Sound Transitions — The sound transitions are all fading in or out. The sound
aspect will be worked on more in a further development of the final project.
3 Task
We have created a prototype of a SG to be able to test the transitions in similar
conditions to the final ones. Asking the testers to be in the environment and wait
will imply they focus more on the environment than on doing a task that can

A Study of Transitional Virtual Environments 43
Fig. 10. Chair transition: this third example of local transition was showy as it depicted
an object breaking into small pieces. Most of the people, fortunately, noticed the event
– especially in the sky – but failed to understand that the chair next to them had
exploded.
inhibit their attention level. Therefore, we implemented the following interaction
using the HTC Vive controllers: they must build robots by assembling their limbs
to the body and giving them weapons or shields. A task overview can be seen
in Figs. 2and 11.
Fig. 11. This drawing shows the general task that the participant has to do. Objects
(a), (b), and (c) describe the VR hardware used in this simulation; entities (d) and
(f) represent two of the main attributes that were used as local transitions; item (e)
illustrates the partially built robot.
Three robot-part sets are available in different colors. The user can choose
whether he respects the color while building the robot. The arms and shields
are on the table, the bodies and weapons are on a shelf and the legs stand on
the floor. The user can grab them by using the Vive controllers trigger buttons.
When a part is grabbed, all the articulations where it can be put together glow in
yellow. When this area overlaps a corresponding articulation, the color changes to

44 M. Sisto et al.
green (Fig. 12a) and, by releasing the part, they are automatically set into place.
When a limb is mounted, we still need to screw it in order to seal it. The user
has to pick up a screw in a container and put it in the correct articulation place
shown by a yellow glowing orb. Then he must screw it completely in (Fig. 12b).
Fig. 12. Renderings of the robot building main task. Image (a) presents a selected
robot arm (surrounded by a yellow sphere) and the area where it has to be fixed is
highlighted by a green sphere; Image (b) depicts a user screwing a limb to the robot.
(Color figure online)
The weapons and shields are immediately sealed when mounted. The sealed
state is used when the robot falls or is thrown out the playing area. All the pieces
that aren’t sealed will be disassembled and placed back to their initial location.
This also works for the screws and screwdriver. The sealed parts will appear on
the floor behind the user.
Since the task was an alibi to distract the user while the transitions were
taking place, it had to be longer than the overall time taken by the transitions
to happen. Not a single user had finished building the three robots in the required
time to do all the transitions, so the estimated time for the task was long enough.
To avoid any frustration, when the transitions were over, the users were allowed
to continue their task so some finished building up the three robots.
The robot assembling and screwing tasks were chosen because they seemed
to be promising tasks for the final SG. They are close to the user usual work
tasks and still allow various gameplay possibilities.
The weapons and shield were thought for the future SG where the goal might
be to build fighting robots. This possibility was explained to the users as the
potential goal of the future game. This gave them a scenario opening and a
purpose to do the task even if no score or any game component were present.
The implemented solution is a contextualized interactive VR experience but it
was not introduced as SG. Most of the users were conscientious in doing the task
successfully and enjoyed it.

A Study of Transitional Virtual Environments 45
4UserTest
A user test was made over five days on 80 people. They were asked to perform
the robot task, which was to assemble robots limbs and screw them in place. The
activity lasted 15 to 20 min, which is the time for all the transitions to occur and
let the user finish his task. The environment transitions were never mentioned
and the users were not aware of any environment change. After the session, the
user had to fill a survey about the environment and the transitions.
4.1 Population
The sample was 40% female and 60% male, and with 84% having never tested
VR or only once. The age range scaled between 12 and 73 years old, with 48%
of them between 20 and 30 years old. The users had very different backgrounds,
but most of them (80%) feeling at ease with the technology.
4.2 Transitions
For each transition taking place, the user was asked if he noticed it while it
was happening. The results show that most of the transitions were not noticed
(see Fig. 13), with only four transitions which are two walls, the table and the
floor noticed by 25% people or more. The living room and the workplace walls
appearing are the two biggest transitions in size, the table is the place where
the task is executed and the floor is where the objects fall; so the chances the
user never looked at those while they were changing are very low. The table
transition is probably one of the most surprising results of this study; the user
main working area was not only changing texture from dark wood to white
marble, but was basically changing size and shape from round to rectangular;
still few people realized such tremendous changes.
If we look at the number of noticed transitions per person, we can see that
nobody remarked all the changes when they were taking place, with a maximum
of 10 transitions seen out of 14 (see Fig. 14), and with 23 people not noticing any
of them. In total, we have 84% of people noticing less than half of the transitions.
4.3 Environments
The results of the questions asked about the transitions show that few of them
were observed. But since the final and starting environment are so different,
you would expect the user to notice at least some change, even after it took
place. This user test shows that it is not the case with 37% of users not noticing
any environmental change at all (see Fig. 15a). As expected, most of the people
that did not notice any environment change noticed zero or one transition (see
Fig. 15b). However, some people noticed up to five transitions, without realizing
that the whole environment was changing.

46 M. Sisto et al.
Fig. 13. Fourteen local transitions and corresponding survey results from the most
noticed (left) to the least (right). The blue and red colors indicate respectively positive
and negative answers. (Color figure online)
Fig. 14. This figure represents how many of the fourteen local transitions were actually
noticed by participants when they occurred: surprisingly 29% of the users did not see
asingleofthem.
4.4 Results
This test results highlight several elements. The first being that environmental
changes do not bother the users in their tasks. This is an important element for
the project continuation. In fact, had transitions been proved to be disturbing
or too distracting, the imagined transitional principle would have had to be
completely redesigned. The transitions proved to be so little disturbing that the
majority was not even noticed, with only 22% of them being observed while they
were taking place.

A Study of Transitional Virtual Environments 47
Fig. 15. (a) Considering the global virtual environment, and after an average of 20 min
in VR, 37% of the candidates did not realize they moved from the middle of a garden
to a working office. (b) Among those people, 25% noted from 2 to 6 transitions.
These results can be due to the fact that users were not aware of the future
environment evolution, and were therefore focused solely on their task, causing
a phenomenon called “Inattentional Blindness” [24], which is the fact of not
noticing a new element because of the concentration on something else. Some
transitions were obviously not seen because they were outside the user’s field of
view, but this is by far not always the case. Most of the transitions happen over
a certain period of time (up to 2 min) with the only transitions that last under
20 seconds are the off-screen appearances as well as the explosion. For all the
other transitions, it is unlikely that the object was never in their field of view
during this time. In addition, many transitions have clearly taken place in the
field of view without them noticing. This blindness phenomenon is such that
37% of users did not see that the environment had changed between the session
beginning and end, when the difference was obvious and right before their eyes.
5 Discussion
5.1 Conclusion
This paper has presented an empirical study relative to the virtual environment
(VE) impact and more specifically to transition from one VE to another. Indeed,
due to real world room constraints, experimenting a virtual reality phenomenon
implies transition issues – at least at the very beginning and end, i.e. from the
real world to the virtual and vice versa.
As developed in the user test Sect. 4, the original objective was to identify
how participants were consciously noticing global VE changes (i.e. from being
in the middle of a garden to a closed indoor office with artificial lights) and/or
local transition (e.g. a tree few meters away virtually walking out of the scene).
This experiment conducted over 80 participants demonstrated the following
results:
– Local object transitions being noticed on an average of 20%;
– About 3 people out of 10 did not see any of the local transitions as they
occurred;

48 M. Sisto et al.
– About 4 participants out of 10 did not even realize that the global environ-
ment changed from a garden to an office.
5.2 Perspective
This encouraging results are the starting point for future work related to under-
standing and identifying the factors that impact the user experience during a
virtual environment change. More specifically we are now conducting investi-
gations on the unconscious influence of the environment (lights, sound, voice,
colors, number of objects, etc.) on manual tasks such as handling in the indus-
trial area.
Acknowledgement. This work was supported by the EU Interreg program, grant
number (contract no.1812) as a part of the SG4H@W project. We would like to thank
all the health professionals that took part in the investigation or contributed otherwise
to this project; many thanks also to the CHUV (University Hospital of Canton Vaud,
Switzerland) for its help and advice.
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