RESEARCH CENTRE

Inria Centre
at Rennes University

2023
ACTIVITY REPORT

IN PARTNERSHIP WITH:

Institut national des sciences appliquées
de Rennes, CNRS, Université de Rennes

Project-Team

HYBRID

3D interaction with virtual environments
using body and mind

IN COLLABORATION WITH: Institut de recherche en informatique et
systèmes aléatoires (IRISA)

DOMAIN

Perception, Cognition and Interaction

THEME

Interaction and visualization

Contents

Project-Team HYBRID

1 Team members, visitors, external collaborators

2 Overall objectives

3 Research program

3.1 Research Axes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

4 Application domains

4.1 Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

5 Social and environmental responsibility

5.1 Impact of research results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

6 Highlights of the year

6.1 Awards . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

1

3

5

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7

8
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8
9

7 New software, platforms, open data

9
9
7.1 New software . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
9
7.1.1 OpenVIBE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
9
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
7.1.2 Xareus
7.1.3 AvatarReady . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
7.1.4 ElectroStim . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
7.2 New platforms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
7.2.1 Immerstar . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

8 New results

12
8.1 Virtual Reality Tools and Usages . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
8.1.1 Assisted walking-in-place: Introducing assisted motion to walking-by-cycling in

embodied virtual reality . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
8.1.2 Assistive robotic technologies for next-generation smart wheelchairs . . . . . . . . . 12
8.1.3 VR for vocational and ecological rehabilitation of patients with cognitive impairment:

a survey . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

8.1.4 Handwriting for efficient text entry in industrial VR applications: Influence of board

orientation and sensory feedback on performance . . . . . . . . . . . . . . . . . . . . 14

8.1.5 Immersive and interactive visualization of 3D spatio-temporal data using a space

time hypercube: Application to cell division and morphogenesis analysis

. . . . . . 14

8.1.6 Can you find your way? Comparing wayfinding behaviour between reality and virtual

reality . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
8.1.7 Deep weathering effects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
8.2 Avatars and Virtual Embodiment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
8.2.1 The sense of embodiment in Virtual Reality and its assessment methods . . . . . . . 17
8.2.2 I’m transforming! Effects of visual transitions to change of avatar on the sense of

embodiment in AR . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

8.2.3 I am a Genius! Influence of virtually embodying Leonardo Da Vinci on creative

performance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18

8.2.4 Beyond my real body: Characterization, impacts, applications and perspectives of

“dissimilar” avatars in Virtual Reality . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19

8.2.5 Now I wanna be a dog: Exploring the impact of audio and tactile feedback on animal

embodiment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

8.2.6 To stick or not to stick? Studying the impact of offset recovery techniques during

mid-air interactions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

8.2.7 Cybersickness, cognition, & motor skills: The effects of music, gender, and gaming

experience . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21

8.3 Haptic Feedback . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
8.3.1 PalmEx: adding palmar force-feedback for 3D manipulation with haptic exoskeleton

gloves . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22

8.3.2 Design, evaluation and calibration of wearable electrotactile interfaces for enhancing

contact information in virtual reality . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22

8.3.3 Tangible avatar: Enhancing presence and embodiment during seated virtual experi-

ences with a prop-based controller

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23

8.3.4 Persuasive vibrations: speech-based vibrations on persuasion, leadership, and co-

presence during verbal communication in VR . . . . . . . . . . . . . . . . . . . . . . . 24

8.3.5 Fostering empathy in social Virtual Reality through physiologically based affective

haptic feedback . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
8.3.6 MultiVibes: What if your VR controller had 10 times more vibrotactile actuators? . . 26
8.3.7 Inducing self-motion sensations with haptic feedback: State-of-the-art and perspect-

ives on “haptic motion” . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
8.3.8 Leveraging tendon vibration to extend pseudo-haptic sensations in VR . . . . . . . . 26
8.3.9 When tangibles become deformable: Studying pseudo-stiffness perceptual thresholds

8.4 Brain Computer Interfaces

in a VR grasping task . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
8.4.1 Design and evaluation of vibrotactile stimulus to support a KMI-based neurofeedback 28
8.4.2 Which sensations should you imagine? . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
8.4.3 Measuring presence in a virtual environment using electroencephalography: A study

of breaks in presence using an oddball paradigm . . . . . . . . . . . . . . . . . . . . . 30

8.4.4 Acceptability of BCI-based procedures for motor rehabilitation after stroke: A ques-

tionnaire study among patients

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30

8.4.5 A large EEG database with users’ profile information for motor imagery brain-

computer interface research . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
8.4.6 Does gender matter in motor imagery BCIs? . . . . . . . . . . . . . . . . . . . . . . . . 31
8.5 Art and Cultural Heritage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
8.5.1 Virtual Reality for the preservation and promotion of historical real tennis . . . . . . 31
8.5.2 De l’imagerie médicale à la réalité virtuelle pour l’archéologie . . . . . . . . . . . . . 32

9 Bilateral contracts and grants with industry

33
9.1 Grants with Industry . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33

10 Partnerships and cooperations

10.1 European initiatives

34
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
10.1.1 H2020 projects
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
10.1.2 Other european programs/initiatives . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
10.2 National initiatives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
10.2.1 ANR . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
10.2.2 PIA . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37
10.2.3 Inria projects
10.3 Regional initiatives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38

11 Dissemination

39
11.1 Promoting scientific activities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
11.1.1 Scientific events: organisation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
11.1.2 Scientific events: selection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
11.1.3 Journal
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
11.1.4 Invited talks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40
11.1.5 Leadership within the scientific community . . . . . . . . . . . . . . . . . . . . . . . . 40
11.1.6 Scientific expertise . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40
11.1.7 Research administration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40
11.2 Teaching - Supervision - Juries . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
11.2.1 Teaching . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41

11.2.2 Supervision . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42
11.2.3 Juries . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43
11.3 Popularization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43
11.3.1 Articles and contents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43
11.3.2 Interventions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44

12 Scientific production

44
12.1 Major publications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45
12.2 Publications of the year
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49
12.3 Cited publications

Project HYBRID

1

Project-Team HYBRID

Creation of the Project-Team: 2013 July 01

Keywords

Computer sciences and digital sciences

A2.5. – Software engineering

A5.1. – Human-Computer Interaction

A5.1.1. – Engineering of interactive systems

A5.1.2. – Evaluation of interactive systems

A5.1.3. – Haptic interfaces

A5.1.4. – Brain-computer interfaces, physiological computing

A5.1.5. – Body-based interfaces

A5.1.6. – Tangible interfaces

A5.1.7. – Multimodal interfaces

A5.1.8. – 3D User Interfaces

A5.1.9. – User and perceptual studies

A5.2. – Data visualization

A5.6. – Virtual reality, augmented reality

A5.6.1. – Virtual reality

A5.6.2. – Augmented reality

A5.6.3. – Avatar simulation and embodiment

A5.6.4. – Multisensory feedback and interfaces

A5.10.5. – Robot interaction (with the environment, humans, other robots)

A6. – Modeling, simulation and control

A6.2. – Scientific computing, Numerical Analysis & Optimization

A6.3. – Computation-data interaction

Other research topics and application domains

B1.2. – Neuroscience and cognitive science

B2.4. – Therapies

B2.5. – Handicap and personal assistances

B2.6. – Biological and medical imaging

B2.8. – Sports, performance, motor skills

B5.1. – Factory of the future

B5.2. – Design and manufacturing

B5.8. – Learning and training

B5.9. – Industrial maintenance

B6.4. – Internet of things

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Inria Annual Report 2023

B8.1. – Smart building/home

B8.3. – Urbanism and urban planning

B9.1. – Education

B9.2. – Art

B9.2.1. – Music, sound

B9.2.2. – Cinema, Television

B9.2.3. – Video games

B9.4. – Sports

B9.6.6. – Archeology, History

Project HYBRID

3

1 Team members, visitors, external collaborators

Research Scientists

• Anatole Lécuyer [Team leader, INRIA, Senior Researcher, HDR]

• Fernando Argelaguet Sanz [INRIA, Researcher, HDR]

• Marc Macé [CNRS, Researcher, HDR]

• Léa Pillette [CNRS, Researcher]

• Justine Saint-Aubert [CNRS, Researcher, from Dec 2023]

Faculty Members

• Bruno Arnaldi [INSA Rennes, Emeritus, HDR]

• Valérie Gouranton [INSA Rennes, Associate Professor, HDR]

• Mélanie Villain [UNIV Rennes, Associate Professor]

Post-Doctoral Fellows

• Elodie Bouzbib [INRIA, until Nov 2023]

• Yann Glemarec [INRIA, Post-Doctoral Fellow, from Oct 2023]

• Francois Le Jeune [INRIA, Post-Doctoral Fellow, from Mar 2023]

• Justine Saint-Aubert [INRIA, until Oct 2023]

• Kyung-Ho Won [INRIA, Post-Doctoral Fellow, from Mar 2023]

PhD Students

• Clément Broutin [CENTRALE Nantes, from Dec 2023]

• Florence Celant-Le Manac’H [CHRU Rennes, UNIV Rennes, from Nov 2023]

• Romain Chabbert [CNRS, from Oct 2023, INSA Rennes]

• Antonin Cheymol [INRIA, INSA Rennes]

• Maxime Dumonteil [UNIV Rennes, from Oct 2023]

• Nicolas Fourrier [Segula Technologies, CIFRE, CENTRALE Nantes]

• Vincent Goupil [Sogea Bretagne, CIFRE, until Oct 2023, INSA Rennes]

• Lysa Gramoli [ORANGE LABS, CIFRE, until Sep 2023, INSA Rennes]

• Martin Guy [CENTRALE Nantes, until Feb 2023]

• Jeanne Hecquard [INRIA, UNIV Rennes]

• Gabriela Herrera Altamira [INRIA and UNIV Lorraine]

• Emilie Hummel [INRIA, INSA Rennes]

• Julien Lomet [UNIV Paris 8, UNIV Rennes]

• Julien Manson [UNIV Rennes, from Oct 2023]

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Inria Annual Report 2023

• Maé Mavromatis [INRIA, until Mar 2023]

• Yann Moullec [UNIV Rennes]

• Grégoire Richard [INRIA, UNIV Lille, until Jun 2023]

• Mathieu Risy [INSA Rennes]

• Tom Roy [INRIA and InterDigital, CIFRE, from Oct 2023, INSA Rennes]

• Sony Saint-Auret [INRIA , INSA Rennes]

• Emile Savalle [UNIV UNIV Rennes]

• Sabrina Toofany [INRIA, from Oct 2023, UNIV Rennes]

• Philippe de Clermont Gallerande [INRIA and InterDigital, CIFRE, from Mar 2023, UNIV Rennes]

Technical Staff

• Alexandre Audinot [INSA Rennes, Engineer]

• Ronan Gaugne [UNIV Rennes, Engineer]

• Lysa Gramoli [INSA Rennes, Engineer, from Nov 2023]

• Anthony Mirabile [INRIA, Engineer, from Oct 2023]

• Florian Nouviale [INSA Rennes, Engineer]

• Thomas Prampart [INRIA, Engineer]

• Adrien Reuzeau [UNIV Rennes, Engineer]

Interns and Apprentices

• Arthur Chaminade [INRIA, Intern, from May 2023 until Oct 2023]

• Lea Driessens [INRIA, Intern, from Feb 2023 until Jun 2023]

• Maxime Dumonteil [INRIA, Intern, from Apr 2023 until Sep 2023]

• Pierre Fayol [UNIV Rennes, Intern, from Mar 2023 until Aug 2023]

• Julien Manson [ENS Rennes, Intern, from Feb 2023 until Aug 2023]

• Vincent Philippe [INRIA, Intern, from May 2023 until Nov 2023]

Administrative Assistant

• Nathalie Denis [INRIA]

External Collaborators

• Rebecca Fribourg [CENTRALE Nantes]

• Guillaume Moreau [IMT Atlantique, HDR]

• Jean-Marie Normand [CENTRALE Nantes, HDR]

Project HYBRID

5

2 Overall objectives

Our research project belongs to the scientific field of Virtual Reality (VR) and 3D interaction with virtual
environments. VR systems can be used in numerous applications such as for industry (virtual prototyping,
assembly or maintenance operations, data visualization), entertainment (video games, theme parks),
arts and design (interactive sketching or sculpture, CAD, architectural mock-ups), education and science
(physical simulations, virtual classrooms), or medicine (surgical training, rehabilitation systems). A major
change that we foresee in the next decade concerning the field of Virtual Reality relates to the emergence
of new paradigms of interaction (input/output) with Virtual Environments (VE).

As for today, the most common way to interact with 3D content still remains by measuring user’s
motor activity, i.e., his/her gestures and physical motions when manipulating different kinds of input
device. However, a recent trend consists in soliciting more movements and more physical engagement
of the body of the user. We can notably stress the emergence of bimanual interaction, natural walking
interfaces, and whole-body involvement. These new interaction schemes bring a new level of complexity
in terms of generic physical simulation of potential interactions between the virtual body and the virtual
surrounding, and a challenging "trade-off" between performance and realism. Moreover, research is also
needed to characterize the influence of these new sensory cues on the resulting feelings of "presence"
and immersion of the user.

Besides, a novel kind of user input has recently appeared in the field of virtual reality: the user’s
mental activity, which can be measured by means of a "Brain-Computer Interface" (BCI). Brain-Computer
Interfaces are communication systems which measure user’s electrical cerebral activity and translate it,
in real-time, into an exploitable command. BCIs introduce a new way of interacting "by thought" with
virtual environments. However, current BCI can only determine a small amount of mental states and
hence a small number of mental commands. Thus, research is still needed here to extend the capacities
of BCI, and to better exploit the few available mental states in virtual environments.

Our first motivation consists thus in designing novel “body-based” and “mind-based” controls of virtual

environments and reaching, in both cases, more immersive and more efficient 3D interaction.

Furthermore, in current VR systems, motor activities and mental activities are always considered
separately and exclusively. This reminds the well-known “body-mind dualism” which is at the heart of
historical philosophical debates. In this context, our objective is to introduce novel “hybrid” interaction
schemes in virtual reality, by considering motor and mental activities jointly, i.e., in a harmonious,
complementary, and optimized way. Thus, we intend to explore novel paradigms of 3D interaction mixing
body and mind inputs. Moreover, our approach becomes even more challenging when considering
and connecting multiple users which implies multiple bodies and multiple brains collaborating and
interacting in virtual reality.

Our second motivation consists thus in introducing a “hybrid approach” which will mix mental and

motor activities of one or multiple users in virtual reality.

3 Research program

The scientific objective of Hybrid team is to improve 3D interaction of one or multiple users with virtual
environments, by making full use of physical engagement of the body, and by incorporating the mental
states by means of brain-computer interfaces. We intend to improve each component of this framework
individually and their subsequent combinations.

The “hybrid” 3D interaction loop between one or multiple users and a virtual environment is depicted
in Figure 1. Different kinds of 3D interaction situations are distinguished (red arrows, bottom): 1) body-
based interaction, 2) mind-based interaction, 3) hybrid and/or 4) collaborative interaction (with at least
two users). In each case, three scientific challenges arise which correspond to the three successive steps
of the 3D interaction loop (blue squares, top): 1) the 3D interaction technique, 2) the modeling and
simulation of the 3D scenario, and 3) the design of appropriate sensory feedback.

The 3D interaction loop involves various possible inputs from the user(s) and different kinds of output
(or sensory feedback) from the simulated environment. Each user can involve his/her body and mind
by means of corporal and/or brain-computer interfaces. A hybrid 3D interaction technique (1) mixes
mental and motor inputs and translates them into a command for the virtual environment. The real-time

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Inria Annual Report 2023

Figure 1: 3D hybrid interaction loop between one or multiple users and a virtual reality system. Top
(in blue) three steps of 3D interaction with a virtual environment: (1-blue) interaction technique, (2-
blue) simulation of the virtual environment, (3-blue) sensory feedbacks. Bottom (in red) different cases
of interaction: (1-red) body-based, (2-red) mind-based, (3-red) hybrid, and (4-red) collaborative 3D
interaction.

simulation (2) of the virtual environment is taking into account these commands to change and update
the state of the virtual world and virtual objects. The state changes are sent back to the user and perceived
through different sensory feedbacks (e.g., visual, haptic and/or auditory) (3). These sensory feedbacks
are closing the 3D interaction loop. Other users can also interact with the virtual environment using the
same procedure, and can eventually “collaborate” using “collaborative interactive techniques” (4).

This description is stressing three major challenges which correspond to three mandatory steps when

designing 3D interaction with virtual environments:

• 3D interaction techniques: This first step consists in translating the actions or intentions of the
user (inputs) into an explicit command for the virtual environment. In virtual reality, the classical
tasks that require such kinds of user command were early classified into four [51]: navigating the
virtual world, selecting a virtual object, manipulating it, or controlling the application (entering
text, activating options, etc). However, adding a third dimension and using stereoscopic rendering
along with advanced VR interfaces cause many 2D techniques to become inappropriate. It is
thus necessary to design specific interaction techniques and adapted tools. This challenge is here
renewed by the various kinds of 3D interaction which are targeted. In our case, we consider various
situations, with motor and/or cerebral inputs, and potentially multiple users.

• Modeling and simulation of complex 3D scenarios: This second step corresponds to the update
of the state of the virtual environment, in real-time, in response to all the potential commands or
actions sent by the user. The complexity of the data and phenomena involved in 3D scenarios is
constantly increasing. It corresponds for instance to the multiple states of the entities present in
the simulation (rigid, articulated, deformable, fluids, which can constitute both the user’s virtual
body and the different manipulated objects), and the multiple physical phenomena implied by
natural human interactions (squeezing, breaking, melting, etc). The challenge consists here in
modeling and simulating these complex 3D scenarios and meeting, at the same time, two strong
constraints of virtual reality systems: performance (real-time and interactivity) and genericity (e.g.,

Project HYBRID

7

multi-resolution, multi-modal, multi-platform, etc).

• Immersive sensory feedbacks: This third step corresponds to the display of the multiple sensory
feedbacks (output) coming from the various VR interfaces. These feedbacks enable the user to
perceive the changes occurring in the virtual environment. They are closing the 3D interaction loop,
making the user immersed, and potentially generating a subsequent feeling of presence. Among the
various VR interfaces which have been developed so far we can stress two kinds of sensory feedback:
visual feedback (3D stereoscopic images using projection-based systems such as CAVE systems
or Head Mounted Displays); and haptic feedback (related to the sense of touch and to tactile or
force-feedback devices). The Hybrid team has a strong expertice in haptic feedback, and in the
design of haptic and “pseudo-haptic” rendering [52]. Note that a major trend in the community,
which is strongly supported by the Hybrid team, relates to a “perception-based” approach, which
aims at designing sensory feedbacks which are well in line with human perceptual capabilities.

These three scientific challenges are addressed differently according to the context and the user
inputs involved. We propose to consider three different contexts, which correspond to the three different
research axes of the Hybrid research team, namely: 1) body-based interaction (motor input only), 2)
mind-based interaction (cerebral input only), and then 3) hybrid and collaborative interaction (i.e., the
mixing of body and brain inputs from one or multiple users).

3.1 Research Axes

The scientific activity of Hybrid team follows three main axes of research:

• Body-based interaction in virtual reality. Our first research axis concerns the design of immersive
and effective "body-based" 3D interactions, i.e., relying on a physical engagement of the user’s body.
This trend is probably the most popular one in VR research at the moment. Most VR setups make
use of tracking systems which measure specific positions or actions of the user in order to interact
with a virtual environment. However, in recent years, novel options have emerged for measuring
“full-body” movements or other, even less conventional, inputs (e.g. body equilibrium). In this
first research axis we focus on new emerging methods of “body-based interaction” with virtual
environments. This implies the design of novel 3D user interfaces and 3D interactive techniques,
new simulation models and techniques, and innovant sensory feedbacks for body-based interaction
with virtual worlds. It involves real-time physical simulation of complex interactive phenomena,
and the design of corresponding haptic and pseudo-haptic feedback.

• Mind-based interaction in virtual reality. Our second research axis concerns the design of im-
mersive and effective “mind-based” 3D interactions in Virtual Reality. Mind-based interaction
with virtual environments relies on Brain-Computer Interface technology, which corresponds to
the direct use of brain signals to send “mental commands” to an automated system such as a
robot, a prosthesis, or a virtual environment. BCI is a rapidly growing area of research and several
impressive prototypes are already available. However, the emergence of such a novel user input
is also calling for novel and dedicated 3D user interfaces. This implies to study the extension of
the mental vocabulary available for 3D interaction with VEs, the design of specific 3D interaction
techniques “driven by the mind” and, last, the design of immersive sensory feedbacks that could
help improve the learning of brain control in VR.

• Hybrid and collaborative 3D interaction. Our third research axis intends to study the combination
of motor and mental inputs in VR, for one or multiple users. This concerns the design of mixed
systems, with potentially collaborative scenarios involving multiple users, and thus, multiple bodies
and multiple brains sharing the same VE. This research axis therefore involves two interdependent
topics: 1) collaborative virtual environments, and 2) hybrid interaction. It should end up with
collaborative virtual environments with multiple users, and shared systems with body and mind
inputs.

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4 Application domains

4.1 Overview

The research program of the Hybrid team aims at next generations of virtual reality and 3D user interfaces
which could possibly address both the “body” and “mind” of the user. Novel interaction schemes are
designed, for one or multiple users. We target better integrated systems and more compelling user
experiences.

The applications of our research program correspond to the applications of virtual reality technologies

which could benefit from the addition of novel body-based or mind-based interaction capabilities:

• Industry: with training systems, virtual prototyping, or scientific visualization;

• Medicine: with rehabilitation and re-education systems, or surgical training simulators;

• Entertainment: with movie industry, content customization, video games or attractions in theme

parks,

• Construction: with virtual mock-ups design and review, or historical/architectural visits.

• Cultural Heritage: with acquisition, virtual excavation, virtual reconstruction and visualization

5 Social and environmental responsibility

5.1 Impact of research results

A salient initiative carried out by Hybrid in relation to social responsibility on the field of health is the
Inria Covid-19 project “VERARE”. VERARE is a unique and innovative concept implemented in record
time thanks to a close collaboration between the Hybrid research team and the teams from the intensive
care and physical and rehabilitation medicine departments of Rennes University Hospital. VERARE
consists in using virtual environments and VR technologies for the rehabilitation of Covid-19 patients,
coming out of coma, weakened, and with strong difficulties in recovering walking. With VERARE, the
patient is immersed in different virtual environments using a VR headset. He is represented by an “avatar”,
carrying out different motor tasks involving his lower limbs, for example : walking, jogging, avoiding
obstacles, etc. Our main hypothesis is that the observation of such virtual actions, and the progressive
resumption of motor activity in VR, will allow a quicker start to rehabilitation, as soon as the patient
leaves the ICU. The patient will then be able to carry out sessions in his room, or even from his hospital
bed, in simple and secure conditions, hoping to obtain a final clinical benefit, either in terms of motor
and walking recovery or in terms of hospital length of stay. The project started at the end of April 2020,
and we were able to deploy a first version of our application at the Rennes hospital in mid-June 2020
only 2 months after the project started. Covid patients are now using our virtual reality application at the
Rennes University Hospital, and the clinical evaluation of VERARE is still on-going and expected to be
achieved and completed in 2024. The project is also pushing the research activity of Hybrid on many
aspects, eg., haptics, avatars, and VR user experience, with 4 papers published in IEEE TVCG in 2022 &
2023.

6 Highlights of the year

• Hiring of Justine Saint-Aubert as CNRS Research Scientist.

• Hiring of Thomas Prampart as Inria Research Engineer.

• Attribution of IEEE VR 2025 conference organization (Anatole Lécuyer and Ferran Argelaguet are

General Chairs)

• Definition of the new team project: Seamless

Project HYBRID

6.1 Awards

9

• IEEE VGTC Virtual Reality Best PhD Dissertation Award (Honorable Mention) - Hugo Brument

7 New software, platforms, open data

7.1 New software

7.1.1 OpenVIBE

Keywords: Neurosciences, Interaction, Virtual reality, Health, Real time, Neurofeedback, Brain-Computer

Interface, EEG, 3D interaction

Functional Description: OpenViBE is a free and open-source software platform devoted to the design,
test and use of Brain-Computer Interfaces (BCI). The platform consists of a set of software modules
that can be integrated easily and efficiently to design BCI applications. The key features of Open-
ViBE software are its modularity, its high performance, its portability, its multiple-user facilities
and its connection with high-end/VR displays. The designer of the platform enables users to build
complete scenarios based on existing software modules using a dedicated graphical language and a
simple Graphical User Interface (GUI). This software is available on the Inria Forge under the terms
of the AGPL licence, and it was officially released in June 2009. Since then, the OpenViBE software
has already been downloaded more than 60000 times, and it is used by numerous laboratories, pro-
jects, or individuals worldwide. More information, downloads, tutorials, videos, documentations
are available on the OpenViBE website.

Release Contributions: Added: - Metabox to perform log of signal power - Artifacted files for algorithm

tests

Changed: - Refactoring of CMake build process - Update wildcards in gitignore - Update CSV File
Writer/Reader - Stimulations only

Removed: - Ogre games and dependencies - Mensia distribution

Fixed: - Intermittent compiler bug

News of the Year: Python2 support dropped in favour of Python3 New feature boxes: - Riemannian
geometry - Multimodal Graz visualisation - Artefact detection - Features selection - Stimulation
validator

Support for Ubuntu 18.04 Support for Fedora 31

URL: http://openvibe.inria.fr

Contact: Anatole Lecuyer

Participants: Cedric Riou, Thierry Gaugry, Anatole Lecuyer, Fabien Lotte, Jussi Lindgren, Laurent

Bougrain, Maureen Clerc Gallagher, Théodore Papadopoulo, Thomas Prampart

Partners: INSERM, GIPSA-Lab

7.1.2 Xareus

Name: Xareus

Keywords: Virtual reality, Augmented reality, 3D, 3D interaction, Behavior modeling, Interactive Scen-

arios

Scientific Description: Xareus mainly contains a scenario engine (#SEVEN) and a relation engine (#FIVE)
#SEVEN is a model and an engine based on petri nets extended with sensors and effectors, enabling
the description and execution of complex and interactive scenarios #FIVE is a framework for the
development of interactive and collaborative virtual environments. #FIVE was developed to answer

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Inria Annual Report 2023

the need for an easier and a faster design and development of virtual reality applications. #FIVE
provides a toolkit that simplifies the declaration of possible actions and behaviours of objects in
a VE. It also provides a toolkit that facilitates the setting and the management of collaborative
interactions in a VE. It is compliant with a distribution of the VE on different setups. It also proposes
guidelines to efficiently create a collaborative and interactive VE.

Functional Description: Xareus is implemented in C# and is available as libraries. An integration to the
Unity3D engine, also exists. The user can focus on domain-specific aspects for his/her application
(industrial training, medical training, etc) thanks to Xareus modules. These modules can be used
in a vast range of domains for augmented and virtual reality applications requiring interactive
environments and collaboration, such as in training. The scenario engine is based on Petri nets
with the addition of sensors and effectors that allow the execution of complex scenarios for driving
Virtual Reality applications. Xareus comes with a scenario editor integrated to Unity 3D for creating,
editing and remotely controlling and running scenarios. The relation engine contains software
modules that can be interconnected and helps in building interactive and collaborative virtual
environments.

Release Contributions: This version is up to date with Unity 3D 2022.3 LTS and includes the rewrite of
most of the visual editor on UIToolkit library. It also add many features and options to customize
the editor Added : - Sections - Multiple sensor/effector on one transition - Negation of sensors -
Website

URL: https://xareus.insa-rennes.fr/

Publications: hal-01147733, hal-01199738, tel-01419698, hal-01086237, hal-01147734

Contact: Valerie Gouranton

Participants: Florian Nouviale, Valerie Gouranton, Bruno Arnaldi, Vincent Goupil, Carl-Johan Jorgensen,

Emeric Goga, Adrien Reuzeau, Alexandre Audinot

7.1.3 AvatarReady

Name: A unified platform for the next generation of our virtual selves in digital worlds

Keywords: Avatars, Virtual reality, Augmented reality, Motion capture, 3D animation, Embodiment

Scientific Description: AvatarReady is an open-source tool (AGPL) written in C#, providing a plugin for
the Unity 3D software to facilitate the use of humanoid avatars for mixed reality applications. Due
to the current complexity of semi-automatically configuring avatars coming from different origins,
and using different interaction techniques and devices, AvatarReady aggregates several industrial
solutions and results from the academic state of the art to propose a simple and fast way to use
humanoid avatars in mixed reality in a seamless way. For example, it is possible to automatically
configure avatars from different libraries (e.g., rocketbox, character creator, mixamo), as well as to
easily use different avatar control methods (e.g., motion capture, inverse kinematics). AvatarReady
is also organized in a modular way so that scientific advances can be progressively integrated into
the framework. AvatarReady is furthermore accompanied by a utility to generate ready-to-use
avatar packages that can be used on the fly, as well as a website to display them and offer them for
download to users.

Functional Description: AvatarReady is a Unity tool to facilitate the configuration and use of humanoid
avatars for mixed reality applications. It comes with a utility to generate ready-to-use avatar
packages and a website to display them and offer them for download.

URL: https://gitlab.inria.fr/avatar/avatarreadypackage

Authors: Ludovic Hoyet, Fernando Argelaguet Sanz, Adrien Reuzeau

Contact: Ludovic Hoyet

Project HYBRID

7.1.4 ElectroStim

11

Keywords: Virtual reality, Unity 3D, Electrotactility, Sensory feedback

Scientific Description: ElectroStim provides an agnostic haptic rendering framework able to exploit
electrical stimulation capabilities, test quickly different prototypes of electrodes, and have a fast
and easy way to author electrotactile sensations so they can quickly be compared when used as
tactile feedback in VR interactions. The framework was designed to exploited electrotactile tactile
feedback but it can also be extended to other tactile rendering system such as vibrotactile feedback.
Furthermore, it is designed to be easily extendable to other types of haptic sensations.

Functional Description: This software provides the tools necessary to control an electrotactile stimu-
lator in Unity 3D. The software allows precise control of the system to generate tactile sensations in
virtual reality applications.

Publication: hal-03799188

Authors: Sebastian Santiago Vizcay, Fernando Argelaguet Sanz

Contact: Fernando Argelaguet Sanz

7.2 New platforms

7.2.1 Immerstar

Participants:

Florian Nouviale, Ronan Gaugne.

URL: Immersia website
With the two virtual reality technological platforms Immersia and Immermove, grouped under the
name Immerstar, the team has access to high-level scientific facilities. This equipment benefits the
research teams of the center and has allowed them to extend their local, national and international
collaborations. In 2023, the Immersia platform was extended to offer a new space dedicated to scientific
experimentations in XR, named ImmerLab (see figure 2). A Photography Rig was also installed. This
system given by Interdigital will allow to explore head/face picture computing and rendering.

We celebrated the twentieth anniversary of the Immersia platform in November 2019 by inaugurating
the new haptic equipment. We proposed scientific presentations and received 150 participants, and visits
for the support services in which we received 50 people.

Since 2021, Immerstar is granted by a PIA3-Equipex+ funding, CONTINUUM. The CONTINUUM
project involves 22 partners and animates a collaborative research infrastructure of 30 platforms located
throughout France. It aims to foster advance interdisciplinary research based on interaction between
computer science and the human and social sciences. Thanks to CONTINUUM, 37 research teams
can develop cutting-edge research programs focusing on visualization, immersion, interaction and
collaboration, as well as on human perception, cognition and behaviour in virtual/augmented reality,
with potential impact on societal issues. CONTINUUM enables a paradigm shift in the way we perceive,
interact, and collaborate with complex digital data and digital worlds by putting humans at the center of
the data processing workflows.

Immerstar is involved in a new National Research Infrastructure since the end of 2021, which gathers

the main platforms of CONTINUUM.

Immerstar is also involved in EUR Digisport led by University of Rennes, H2020 EU projects GuestXR

and Share Space, and PIA4 DemoES AIR led by University of Rennes.

In october 2023, the team of the platform has been strengthened by the recruitment of a permanent
research engineer by the University of Rennes, Adrien Reuzeau. Immerstar was also granted in 2023
by a CPER funding for a 2 years position of a University Rennes 2 research engineer dedicated to the
development of partnership with private entities.

Immersia also hosted teaching activities for students from INSA Rennes, ENS Rennes, and University

of Rennes.

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Inria Annual Report 2023

Figure 2: Immersia platform: (Left) “Scale-One” Haptic system for one or two users. (Right) Motion
platform for a powered wheelchair simulation.

8 New results

8.1 Virtual Reality Tools and Usages

8.1.1 Assisted walking-in-place: Introducing assisted motion to walking-by-cycling in embodied

virtual reality

Participants:

Yann Moullec, Mélanie Cogné (contact),
Anatole Lécuyer.

Justine Saint-Aubert,

In this work [28], we investigate the use of a motorized bike to support the walk of a self-avatar
in Virtual Reality (VR). While existing walking-in-place (WIP) techniques render compelling walking
experiences, they can be judged repetitive and strenuous. Our approach consists in assisting a WIP
technique so that the user does not have to actively move in order to reduce effort and fatigue. We chose
to assist a technique called walking-by-cycling, which consists in mapping the cycling motion of a bike
onto the walking of the user’s self-avatar, by using a motorized bike (see figure 3). We expected that our
approach could provide participants with a compelling walking experience while reducing the effort
required to navigate. We conducted a within-subjects study where we compared "assisted walking-by-
cycling" to a traditional active walking-by-cycling implementation, and to a standard condition where
the user is static. In the study, we measured embodiment, including ownership and agency, walking
sensation, perceived effort and fatigue. Results showed that assisted walking-by-cycling induced more
ownership, agency, and walking sensation than the static simulation. Additionally, assisted walking-by-
cycling induced levels of ownership and walking sensation similar to that of active walking-by-cycling, but
it induced less perceived effort. Taken together, this work promotes the use of assisted walking-by-cycling
in situations where users cannot or do not want to exert much effort while walking in embodied VR such
as for injured or disabled users, for prolonged uses, medical rehabilitation, or virtual visits.

8.1.2 Assistive robotic technologies for next-generation smart wheelchairs

Project HYBRID

13

Figure 3: We introduce assisted motion to walking-by-cycling using a motorized bike (left). The user
embodies an avatar which is viewed in first-person perspective (right). The bike drives the user’s legs in a
cycling motion, which makes the avatar walk in synchrony (middle) without requiring effort from the
user.

Participants:

Valérie Gouranton (contact).

This work [27] describes the robotic assistive technologies developed for users of electrically powered
wheelchairs, within the framework of the European Union’s Interreg ADAPT (Assistive Devices for Em-
powering Disabled People Through Robotic Technologies) project. In particular, special attention is de-
voted to the integration of advanced sensing modalities and the design of new shared control algorithms.
In response to the clinical needs identified by our medical partners, two novel smart wheelchairs with
complementary capabilities and a virtual reality (VR)-based wheelchair simulator have been developed
(see figure 4). These systems have been validated via extensive experimental campaigns in France and
the United Kingdom.

Figure 4: The wheelchair simulator tested by a volunteer in immersive conditions.

This work was done in collaboration with Inria RAINBOW Team, MIS - Modélisation Information et
Systèmes - UR UPJV 4290, University College of London, Pôle Saint-Hélier - Médecine Physique et de

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Inria Annual Report 2023

Réadaptation [Rennes], CNRS-AIST JRL - Joint Robotics Laboratory and IRSEEM - Institut de Recherche
en Systèmes Electroniques Embarqués.

8.1.3 VR for vocational and ecological rehabilitation of patients with cognitive impairment: a survey

Participants:

Emilie Hummel, Mélanie Cogné (contact), Anatole Lécuyer,
Valérie Gouranton.

Cognitive impairment arises from various brain injuries or diseases, such as traumatic brain injury,
stroke, schizophrenia, or cancer-related cognitive impairment. Cognitive impairment can be an obstacle
for patients to the return-to-work. Research suggests various interventions using technology for cognitive
and vocational rehabilitation. This work [23] offers an overview of sixteen vocational or ecological VR-
based clinical studies among patients with cognitive impairment. The objective is to analyze these
studies from a VR perspective focusing on the VR apparatus and tasks, adaptivity, transferability, and
immersion of the interventions. Our results highlight how a higher level of immersion could bring the
participants to a deeper level of engagement and transferability, rarely assessed in current literature, and
a lack of adaptivity in studies involving patients with cognitive impairments. From these considerations,
we discuss the challenges of creating a standardized yet adaptive protocol and the perspectives of
using immersive technologies to allow precise monitoring, personalized rehabilitation and increased
commitment.

This work was done in collaboration with the Service de recherche clinique du Centre François
Baclesse, ANTICIPE - Unité de recherche interdisciplinaire pour la prévention et le traitement des cancers
and the CHU of Caen.

8.1.4 Handwriting for efficient text entry in industrial VR applications: Influence of board orientation

and sensory feedback on performance

Participants: Guillaume Moreau, Jean-Marie Normand (contact).

Text entry in Virtual Reality (VR) is becoming an increasingly important task as the availability of
hardware increases and the range of VR applications widens. This is especially true for VR industrial
applications where users need to input data frequently. Large-scale industrial adoption of VR is still
hampered by the productivity gap between entering data via a physical keyboard and VR data entry
methods. Data entry needs to be efficient, easy-to-use and to learn and not frustrating. In this work [19],
we present a new data entry method based on handwriting recognition (HWR). Users can input text by
simply writing on a virtual surface. We conduct a user study to determine the best writing conditions
when it comes to surface orientation and sensory feedback. This feedback consists of visual, haptic, and
auditory cues (see figure 5). We find that using a slanted board with sensory feedback is best to maximize
writing speeds and minimize physical demand. We also evaluate the performance of our method in terms
of text entry speed, error rate, usability and workload. The results show that handwriting in VR has high
entry speed, usability with little training compared to other controller-based virtual text entry techniques.
The system could be further improved by reducing high error rates through the use of more efficient
handwriting recognition tools. In fact, the total error rate is 9.3% in the best condition. After 40 phrases of
training, participants reach an average of 14.5 WPM, while a group with high VR familiarity reach 16.16
WPM after the same training. The highest observed textual data entry speed is 21.11 WPM.

This work was done in collaboration with Segula Technologies.

8.1.5 Immersive and interactive visualization of 3D spatio-temporal data using a space time hyper-

cube: Application to cell division and morphogenesis analysis

Project HYBRID

15

Figure 5: The user can write words by hand on a board in the virtual environment. Handwriting re-
cognition technology converts the handwritten word into usable text data (left). During the user study,
participants are presented with phrases they have to write one word at a time (right). The yellow word is
the selected word. Green words are correctly recognized and red words are not. Users are presented with
multiple recognition results they can choose from.

Participants: Gwendal Fouché, Ferran Argelaguet (contact).

The analysis of multidimensional time-varying datasets faces challenges, notably regarding the
representation of the data and the visualization of temporal variations. In this work [18], we proposed
an extension of the well-known Space-Time Cube (STC) visualization technique in order to visualize
time-varying 3D spatial data, taking advantage of the interaction capabilities of Virtual Reality (VR). First,
we propose the Space-Time Hypercube (STH) as an abstraction for 3D temporal data, extended from
the STC concept. Second, through the example of embryo development imaging dataset, we detail the
construction and visualization of a STC based on a user-driven projection of the spatial and temporal
information. This projection yields a 3D STC visualization, which can also encode additional numerical
and categorical data (see figure 6). Additionally, we propose a set of tools allowing the user to filter and
manipulate the 3D STC which benefits the visualization, exploration and interaction possibilities offered
by VR. Finally, we evaluated the proposed visualization method in the context of 3D temporal cell imaging
data analysis, through a user study (n = 5) reporting the feedback from five biologists. These domain
experts also accompanied the application design as consultants, providing insights on how the STC
visualization could be used for the exploration of complex 3D temporal morphogenesis data.

Figure 6: From a cross-section on the 3D surface-based temporal data shown on the first figure, we
generate a Space-Time Cube visualization, displayed in the second image, showing the evolution over
time of the spatial data of the cross-section displayed on the x and y axes. The third picture shows how
the visualization can be enriched with quantitative and qualitative data using different color coding. A
set of interaction tools help the user to explore the generated visualization, as seen in the last image.

This work was done in collaboration with Inria Serpico team and the LIRMM.

8.1.6 Can you find your way? Comparing wayfinding behaviour between reality and virtual reality

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Inria Annual Report 2023

Participants:

Vincent Goupil, Bruno Arnaldi, Ferran Argelaguet, Valérie Gour-
anton (contact).

Signage is an essential element in finding one’s way and avoiding getting lost in open and indoor
environments. Yet, designing an effective signage system for a complex structure remains a challenge, as
some buildings may need to communicate a lot of information in a minimum amount of space. Virtual
reality (VR) provides a new way of studying human wayfinding behaviour, offering a flexible and cost-
effective platform for assessing the efficiency of signage, especially during the design phase of a building.
However, it is not yet clear whether wayfinding behaviour and signage interpretation differ between reality
and virtual reality. We conducted a wayfinding experiment [34] using signage with 20 participants who
performed a series of tasks in virtual and real conditions (see figure 7). Participants were video-recorded
in both conditions. In addition, oral feedback and post-experiment questionnaires were collected as
supplementary data. The aim of this study was to investigate the wayfinding behaviour of a user using
signs in an unfamiliar real and virtual environment. The results of the experiment showed a similarity
in behaviour between both environments; regardless of the order of passage and the environment,
participants required less time to complete the task during the second run by reducing their mistakes
and learning from their first run.

Figure 7: Illustration of users executing a wayfinding task thanks to signage elements in real conditions
and virtual conditions. (Left) A user in real conditions equipped with a head-mounted camera and an
orange file in their hand. (Right) A user in virtual conditions equipped with a virtual reality Head-Mounted
Display (HMD).

This work was done in collaboration with Vinci Construction and Sogea Bretagne.

8.1.7 Deep weathering effects

Participants:

Jean-Marie Normand (contact), Guillaume Moreau.

Weathering phenomena are ubiquitous in urban environments, where it is easy to observe severely de-
graded old buildings as a result of water penetration. Despite being an important part of any realistic city,
this kind of phenomenon has received little attention from the Computer Graphics community compared
to stains resulting from biological or flow effects on the building exteriors. In this work [29], we present
physically-inspired deep weathering effects, where the penetration of humidity (i.e., water particles) and
its interaction with a building’s internal structural elements result in large, visible degradation effects.
Our implementation is based on a particle-based propagation model for humidity propagation, coupled
with a spring-based interaction simulation that allows chemical interactions, like the formation of rust,
to deform and destroy a building’s inner structure. To illustrate our methodology, we show a collection of
deep degradation effects applied to urban models involving the creation of rust or of ice within walls (see
figure 8).

This work was done in collaboration with Univ. Gérone (Spain).

Project HYBRID

17

Figure 8: A building with deep weathering effects. Left: the original building. Middle: the same building
after the simulation of water particles penetrating the gray area. Right, a closeup view of the resulting
degradation is due to weathering effects. Surface noise is part of the wall texture itself.

8.2 Avatars and Virtual Embodiment

8.2.1 The sense of embodiment in Virtual Reality and its assessment methods

Participants: Martin Guy, Jean-Marie Normand (contact), Guillaume Moreau.

The sense of embodiment refers to the sensations of being inside, having, and controlling a body.
In virtual reality, it is possible to substitute a person’s body with a virtual body, referred to as an avatar.
Modulations of the sense of embodiment through modifications of this avatar have perceptual and
behavioural consequences on users that can influence the way users interact with the virtual environment.
Therefore, it is essential to define metrics that enable a reliable assessment of the sense of embodiment in
virtual reality to better understand its dimensions, the way they interact, and their influence on the quality
of interaction in the virtual environment. In this work [21], we first introduce the current knowledge on
the sense of embodiment, its dimensions (senses of agency, body ownership, and self-location), and how
they relate the ones with the others (see figure 9). Then, we dive into the different methods currently
used to assess the sense of embodiment, ranging from questionnaires to neurophysiological measures.
We provide a critical analysis of the existing metrics, discussing their advantages and drawbacks in
the context of virtual reality. Notably, we argue that real-time measures of embodiment, which are
also specific and do not require double tasking, are the most relevant in the context of virtual reality.
Electroencephalography seems a good candidate for the future if its drawbacks (such as its sensitivity to
movement and practicality) are improved. While the perfect metric has yet to be identified if it exists,
this work provides clues on which metric to choose depending on the context, which should hopefully
contribute to better assessing and understanding the sense of embodiment in virtual reality.

This work was done in collaboration with INCIA (Bordeaux).

8.2.2 I’m transforming! Effects of visual transitions to change of avatar on the sense of embodiment

in AR

Participants:

Anatole Lécuyer (contact), Adélaïde Genay.

Virtual avatars are more and more often featured in Virtual Reality (VR) and Augmented Reality
(AR) applications. When embodying a virtual avatar, one may desire to change of appearance over the
course of the embodiment. However, switching suddenly from one appearance to another can break the
continuity of the user experience and potentially impact the sense of embodiment (SoE), especially when
the new appearance is very different. In this work [36], we explore how applying smooth visual transitions
at the moment of the change can help to maintain the SoE and benefit the general user experience. To

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Inria Annual Report 2023

Figure 9: Visualisation of the current knowledge about the interdependence of the different components of
the SoE. The SoA and SoBO are, depending on the context, sometimes found independent and sometimes
found to be linked. Moreover, it has been found that they are processed separately by two distinct brain
regions, and a third region aggregates information at a higher level. The SoSL, while less studied, seems
to have some interaction with the SoA. The SoSL and SoBO are strongly linked.

address this, we implemented an AR system allowing users to embody a regular-shaped avatar that can be
transformed into a muscular one through a visual effect (see figure 10). The avatar’s transformation can
be triggered either by the user through physical action (“active” transition), or automatically launched
by the system (“passive” transition). We conducted a user study to evaluate the effects of these two
types of transformations on the SoE by comparing them to control conditions where there was no visual
feedback of the transformation. Our results show that changing the appearance of one’s avatar with an
active transition (with visual feedback), compared to a passive transition, helps to maintain the user’s
sense of agency, a component of the SoE. They also partially suggest that the Proteus effects experienced
during the embodiment were enhanced by these transitions. Therefore, we conclude that visual effects
controlled by the user when changing their avatar’s appearance can benefit their experience by preserving
the SoE and intensifying the Proteus effects.

This work was done in collaboration with NAIST and Inria POTIOC team.

8.2.3 I am a Genius! Influence of virtually embodying Leonardo Da Vinci on creative performance

Participants:

Anatole Lécuyer (contact).

Virtual reality (VR) provides users with the ability to substitute their physical appearance by embody-
ing virtual characters (avatars) using head-mounted displays and motion-capture technologies. Previous
research demonstrated that the sense of embodiment toward an avatar can impact user behavior and
cognition. In this work [20], we present an experiment designed to investigate whether embodying a
well-known creative genius could enhance participants’ creative performance. Following a preliminary
online survey to select a famous character suited to the purpose of this study, we developed a VR applica-
tion allowing participants to embody Leonardo da Vinci (see figure 11) or a self-avatar. Self-avatars were
approximately matched with participants in terms of skin tone and morphology. 40 participants took
part in three tasks seamlessly integrated in a virtual workshop. The first task was based on a Guilford’s
Alternate Uses test (GAU) to assess participants’ divergent abilities in terms of fluency and originality. The
second task was based on a Remote Associates Test (RAT) to evaluate convergent abilities. Lastly, the third
task consisted in designing potential alternative uses of an object displayed in the virtual environment

Project HYBRID

19

Figure 10: Avatars used in our experiment. The upper left (A) and right (B) are female regular and
muscular-shaped avatars, respectively. The bottom left (C) and right (D) are male avatars.

using a 3D sketching tool. Participants embodying Leonardo da Vinci demonstrated significantly higher
divergent thinking abilities, with a substantial difference in fluency between the groups. Conversely, par-
ticipants embodying a self-avatar performed significantly better in the convergent thinking task. Taken
together, these results promote the use of our virtual embodiment approach, especially in applications
where divergent creativity plays an important role, such as design and innovation.

Figure 11: Leonardo da Vinci’s virtual workshop designed for the experiment.

This work was done in collaboration with Arts et Métiers.

8.2.4 Beyond my real body: Characterization, impacts, applications and perspectives of “dissimilar”

avatars in Virtual Reality

Participants:

Antonin Cheymol, Rebecca Fribourg (contact), Anatole Lécuyer, Jean-
Marie Normand, Ferran Argelaguet.

In virtual reality, the avatar - the user’s digital representation - is an important element which can
drastically influence the immersive experience. In this work, we especially focus on the use of “dissimilar”
avatars i.e., avatars diverging from the real appearance of the user, whether they preserve an anthropo-
morphic aspect or not (see figure 12). Previous studies reported that dissimilar avatars can positively

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impact the user experience, in terms for example of interaction, perception or behaviour. However, given
the sparsity and multi-disciplinary character of research related to dissimilar avatars, it tends to lack
common understanding and methodology, hampering the establishment of novel knowledge on this
topic. In this work [15], we propose to address these limitations by discussing: (I) a methodology for
dissimilar avatars characterization, (ii) their impacts on the user experience, (iii) their different fields of
application, and finally, (iv) future research direction on this topic. Taken together, we believe that this
work can support future research related to dissimilar avatars, and help designers of VR applications to
leverage dissimilar avatars appropriately.

Figure 12: Visual representation of the presented atomic taxonomy applied to a virtual hand.

8.2.5 Now I wanna be a dog: Exploring the impact of audio and tactile feedback on animal embodi-

ment

Participants:

Rebecca Fribourg (contact).

Embodying a virtual creature or animal in Virtual Reality (VR) is becoming common, and can have
numerous beneficial impacts. For instance, it can help actors improve their performance of a computer-
generated creature, or it can endow the user with empathy towards threatened animal species. However,
users must feel a sense of embodiment towards their virtual representation, commonly achieved by
providing congruent sensory feedback. Providing effective visuo-motor feedback in dysmorphic bodies
can be challenging due to human-animal morphology differences. Thus, the purpose of this work [41] was
to experiment with the inclusion of audio and audio-tactile feedback to begin unveiling their influence
towards animal avatar embodiment (see figure 13). Two experiments were conducted to examine the
effects of different sensory feedback on participants’ embodiment in a dog avatar in an Immersive Virtual
Environment (IVE). The first experiment (n= 24) included audio, tactile, audio-tactile, and baseline
conditions. The second experiment (n= 34) involved audio and baseline conditions only.

This work was done in collaboration with TCD (Trinity College Dublin).

8.2.6 To stick or not to stick? Studying the impact of offset recovery techniques during mid-air

interactions

Participants: Maé Mavromatis, Anatole Lécuyer, Ferran Argelaguet (contact).

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Figure 13: (1) Dog avatar being brushed by the virtual character and (2) the experimenter brushing
the participant’s back for the tactile condition. (3) View of the virtual shelter and (4) virtual character
trimming the dog avatar’s fur using scissors.

During mid-air interactions, common approaches (such as the god-object method) typically rely on
visually constraining the user’s avatar to avoid visual interpenetrations with the virtual environment in
the absence of kinesthetic feedback. In this work we explored two methods which influence how the
position mismatch (positional offset) between users’ real and virtual hands is recovered when releasing
the contact with virtual objects [26]. The first method (sticky) constrains the user’s virtual hand until
the mismatch is recovered, while the second method (unsticky) employs an adaptive offset recovery
method. In the first study, we explored the effect of positional offset and of motion alteration on users’
behavioral adjustments and users’ perception. In a second study, we evaluated variations in the sense
of embodiment and the preference between the two control laws. Overall, both methods presented
similar results in terms of performance and accuracy, yet, positional offsets strongly impacted motion
profiles and users’ performance. Both methods also resulted in comparable levels of embodiment. Finally,
participants usually expressed strong preferences toward one of the two methods, but these choices
were individual-specific and did not appear to be correlated solely with characteristics external to the
individuals. Taken together, these results highlight the relevance of exploring the customization of motion
control algorithms for avatars.

This work was done in collaboration with Inria Virtus team.

8.2.7 Cybersickness, cognition, & motor skills: The effects of music, gender, and gaming experience

Participants:

Panagiotis Kourtesis, Ferran Argelaguet (contact).

Recent research has attempted to identify methods to mitigate cybersickness and examine its afteref-
fects. In this direction, this work [24] examined the effects of cybersickness on cognitive, motor, and
reading performance in VR (see figure 14). Also, this work evaluates the mitigating effects of music on
cybersickness, as well as the role of gender, and the computing, VR, and gaming experience of the user.
This work reports on two studies. In the 1st study, 92 participants selected the music tracks considered
most calming (low valence) or joyful (high valence) to be used in the 2nd study. In the 2nd study, 39 parti-
cipants performed an assessment four times, once before the rides (baseline), and then once after each
ride (3 rides). In each ride either Calming, or Joyful, or No Music was played. During each ride, linear and
angular accelerations took place to induce cybersickness in the participants. In each assessment, while
immersed in VR, the participants evaluated their cybersickness symptomatology and performed a verbal
working memory task, a visuospatial working memory task, and a psychomotor task. While responding
to the cybersickness questionnaire (3D UI), eye-tracking was conducted to measure reading time and
pupillometry. The results showed that Joyful and Calming music substantially decreased the intensity of
nausea-related symptoms. However, only Joyful music significantly decreased the overall cybersickness
intensity. Importantly, cybersickness was found to decrease verbal working memory performance and
pupil size. Also, it significantly decelerated psychomotor (reaction time) and reading abilities. Higher
gaming experience was associated with lower cybersickness. When controlling for gaming experience,
there were no significant differences between female and male participants in terms of cybersickness.
The outcomes indicated the efficiency of music in mitigating cybersickness, the important role of gaming
experience in cybersickness, and the significant effects of cybersickness on pupil size, cognition, psy-
chomotor skills, and reading ability. Another publication related to this work [25] compare and validate

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Cybersickness in Virtual Reality Questionnaire (CSQ-VR) with SSQ and VRSQ questionnaires.

Figure 14: Examples of accelerations in VR used during the experiment: Linear (left) and Angular (centre
and right). Note that the direction of the motion was forward.

This work was done in collaboration with the University of Edinburgh.

8.3 Haptic Feedback

8.3.1 PalmEx: adding palmar force-feedback for 3D manipulation with haptic exoskeleton gloves

Participants:

Anatole Lécuyer (contact), Elodie Bouzbib.

Haptic exoskeleton gloves are a widespread solution for providing force-feedback in Virtual Reality
(VR), especially for 3D object manipulations. However, they are still lacking an important feature re-
garding in-hand haptic sensations: the palmar contact. In this work [14] we present PalmEx, a novel
approach which incorporates palmar force-feedback into exoskeleton gloves to improve the overall
grasping sensations and manual haptic interactions in VR. PalmEx’s concept is demonstrated through a
self-contained hardware system augmenting a hand exoskeleton with an encountered palmar contact
interface-physically encountering the users’ palm (see figure 15). We build upon current taxonomies
to elicit PalmEx’s capabilities for both the exploration and manipulation of virtual objects. We first
conduct a technical evaluation optimising the delay between the virtual interactions and their physical
counterparts. We then empirically evaluate PalmEx’s proposed design space in a user study (n=12) to
assess the potential of a palmar contact for augmenting an exoskeleton. Results show that PalmEx offers
the best rendering capabilities to perform believable grasps in VR. PalmEx highlights the importance of
the palmar stimulation, and provides a low-cost solution to augment existing high-end consumer hand
exoskeletons.

This work was done in collaboration with Inria RAINBOW team.

8.3.2 Design, evaluation and calibration of wearable electrotactile interfaces for enhancing contact

information in virtual reality

Participants:

Sebastian Vizcay, Panagiotis Kourtesis, Ferran Argelaguet (contact).

Electrotactile feedback is a convenient tactile rendering method thanks to reduced form factor
and power consumption. Yet, its usage in immersive virtual reality has been scarcely addressed. This
work [30] explores how electrotactile feedback could be used to enhance contact information for mid-air
interactions in virtual reality (see figure 16). We propose an electrotactile rendering method which
modulates the perceived intensity of the electrotactile stimuli according to the interpenetration distance
between the user’s finger and the virtual surface. In a first user study (N=21), we assessed the performance
of our method against visual interpenetration feedback and no-feedback. Contact precision and accuracy

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Figure 15: PalmEx interface. (a) The user’s palm is unencumbered prior to interaction. (b) The palmar
interface goes towards his/her palm while the user starts gesturing a grasp. (c) When engaging the grasp,
the user perceives force-feedback from both the exoskeleton and the palmar interface.

were significantly improved when using interpenetration feedback. The results also showed that the
calibration of the electrotactile stimuli was key, which motivated a second study exploring how the
calibration procedure could be improved. In a second study (N=16), we compared two calibration
techniques: a non-VR keyboard and a VR direct interaction method. While the two methods provided
comparable usability and calibration accuracy, the VR method was significantly faster. These results pave
the way for the usage of electrotactile feedback as an efficient alternative to visual feedback for enhancing
contact information in virtual reality.

Figure 16: Experimental apparatus. The electrical stimulator is attached to the forearm and the electrode
is placed in contact with the finger pad. The two insets represent detailed views of the electrode. The
user’s hand is tracked by a HTC Vive Tracker.

This work was done in collaboration with Inria RAINBOW team.

8.3.3 Tangible avatar: Enhancing presence and embodiment during seated virtual experiences with

a prop-based controller

Participants:

Justine Saint-Aubert (contact), Ferran Argelaguet, Anatole Lécuyer.

We investigate [39] using a prop to control human-like avatars in virtual environments while remaining

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seated. We believe that manipulating a tangible interface, capable of rendering physical sensations and
reproducing the movements of an avatar, could lead to a greater virtual experience (presence) and
strengthen the relationship between users and the avatar (embodiment) compared to other established
controllers. We present a controller based on an instrumented artist doll that users can manipulate to
move the avatar in virtual environments (see figure 17). We evaluated the influence of such a controller
on the sense of presence and the sense of embodiment in 3 perspectives (third person perspective on a
screen, immersive third-person perspective, and immersive first-person perspective in a head-mounted
display). We compared the controller with gamepad controllers to control the movements of an avatar
in a kick-in-a-ball game as illustration. The results showed that the prop-based controller can increase
the sense of presence and fun in all three perspectives. It also enhances the sense of embodiment in the
immersive perspectives. It could therefore enhance the user experience in various simulations involving
human-like avatars.

Figure 17: We propose to use a tangible prop to control a human-like avatar during seated virtual
experiences. By manipulating the prop, users perform kinematics similar to those of the avatar and
experience physical interactions with it. We show that such controllers can enhance the sense of presence
and embodiment compared to traditional gamepad controllers.

8.3.4 Persuasive vibrations: speech-based vibrations on persuasion, leadership, and co-presence

during verbal communication in VR

Participants:

Justine Saint-Aubert (contact), Ferran Argelaguet, Marc Macé,
Anatole Lécuyer.

In Virtual Reality (VR), a growing number of applications involve verbal communications with avatars,
such as for teleconference, entertainment, virtual training, social networks, etc. In this context, our
work [40] aims to investigate how tactile feedback consisting in vibrations synchronized with speech could
influence aspects related to VR social interactions such as persuasion, co-presence and leadership. We
conducted two experiments where participants embody a first-person avatar attending a virtual meeting
in immersive VR (see figure 18). In the first experiment, participants were listening to two speaking
virtual agents and the speech of one agent was augmented with vibrotactile feedback. Interestingly, the
results show that such vibrotactile feedback could significantly improve the perceived co-presence but
also the persuasiveness and leadership of the haptically-augmented agent. In the second experiment,
the participants were asked to speak to two agents, and their own speech was augmented or not with
vibrotactile feedback. The results show that vibrotactile feedback had again a positive effect on co-
presence, and that participants perceive their speech as more persuasive in presence of haptic feedback.
Taken together, our results demonstrate the strong potential of haptic feedback for supporting social
interactions in VR, and pave the way to novel usages of vibrations in a wide range of applications in which
verbal communication plays a prominent role.

This work was done in collaboration with Inria RAINBOW team and Ivcher’s institute (Israel).

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Figure 18: We investigated whether reinforcing speech with vibrotactile feedback displayed in users’ hand
could improve perceived persuasion, leadership, and co-presence when users listen to agents (left) or
when users talk to agents (right) in Virtual Reality.

8.3.5 Fostering empathy in social Virtual Reality through physiologically based affective haptic

feedback

Participants:

Jeanne Hecquard,
Anatole Lécuyer, Marc Macé (contact).

Justine Saint-Aubert,

Ferran Argelaguet,

We study the promotion of positive social interactions in VR by fostering empathy with other users
present in the virtual scene. For this purpose [35], we propose using affective haptic feedback to rein-
force the connection with another user through the direct perception of their physiological state. We
developed a virtual meeting scenario where a human user attends a presentation with several virtual
agents. Throughout the meeting, the presenting virtual agent faces various difficulties that alter her stress
level. The human user directly feels her stress via two physiologically based affective haptic interfaces: a
compression belt and a vibrator, simulating the breathing and the heart rate of the presenter, respect-
ively (see figure 19). We conducted a user study that compared the use of such a "sympathetic" haptic
rendering vs an "indifferent" one that does not communicate the presenter’s stress status, remaining
constant and relaxed at all times. Results are rather contrasted and user-dependent, but they show that
sympathetic haptic feedback is globally preferred and can enhance empathy and perceived connection
to the presenter. The results promote the use of affective haptics in social VR applications, in which
fostering positive relationships plays an important role.

Figure 19: User experiencing the scenario in VR while wearing the haptic system. He is artificially
connected to a virtual presenter by means of a physiologically based haptic feedback. He can ”feel”
the presenter’s stress and relief through a virtual breathing and heartbeat rendering achieved using the
compression belt wrapped around the torso and the vibrotactile feedback on the left wrist.

This work was done in collaboration with Inria RAINBOW team.

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8.3.6 MultiVibes: What if your VR controller had 10 times more vibrotactile actuators?

Participants: Grégoire Richard, Ferran Argelaguet, Anatole Lécuyer (contact).

Consumer-grade virtual reality (VR) controllers are typically equipped with one vibrotactile actuator,
allowing to create simple and non-spatialized tactile sensations through the vibration of the entire
controller. Leveraging the funneling effect, an illusion in which multiple vibrations are perceived as a
single one, in this work [38], we proposed MultiVibes, a VR controller capable of rendering spatialized
sensations at different locations on the user’s hand and fingers. The designed prototype includes ten
vibrotactile actuators, directly in contact with the skin of the hand, limiting the propagation of vibrations
through the controller (see figure 20). We evaluated MultiVibes through two controlled experiments.
The first one focused on the ability of users to recognize spatio-temporal patterns, while the second one
focused on the impact of MultiVibes on the users’ haptic experience when interacting with virtual objects
they can feel. Taken together, the results show that MultiVibes is capable of providing accurate spatialized
feedback and that users prefer MultiVibes over recent VR controllers.

Figure 20: (a) MultiVibes prototype comprising 10 actuators in contact with the skin that can be controlled
individually in amplitude and frequency. (b) Interaction with the edge of a virtual cube. (c) As the user
slides the controller along the edge of the cube, they feel a phantom vibration point moving inside their
hand according to the point of contact. The vibration point location is determined by the three closest
actuators, controlled using our funneling model.

This work was done in collaboration with INRIA LOKI team.

8.3.7 Inducing self-motion sensations with haptic feedback: State-of-the-art and perspectives on

“haptic motion”

Participants:

Anatole Lécuyer (contact).

While virtual reality applications flourish, there is a growing need for technological solutions to induce
compelling self-motion, as an alternative to cumbersome motion platforms. Haptic devices target the
sense of touch, yet more and more researchers managed to address the sense of motion by means of
specific and localized haptic stimulations. This innovative approach constitutes a specific paradigm
that can be called “haptic motion”. This work [16] aims to introduce, formalize, survey and discuss
this relatively new research field. First, we summarize some core concepts of self-motion perception,
and propose a definition of the haptic motion approach based on three criteria. Then, we present a
summary of existing related literature, from which we formulate and discuss three research problems
that we estimate key for the development of the field: the rationale to design a proper haptic stimulus,
the methods to evaluate and characterize self-motion sensations, and the usage of multimodal motion
cues (see figure 21).

8.3.8 Leveraging tendon vibration to extend pseudo-haptic sensations in VR

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Figure 21: Self-motion sensations are usually induced by means of a motion platform displacing the
whole body. The use of local haptic stimulation to simulate self-motion (instead of physical contacts with
the virtual environment) constitutes an emergent approach, that we define as “haptic motion”.

Participants:

Ferran Argelaguet, Anatole Lécuyer (contact).

The Pseudo-haptic technique is used to modify haptic perception by appropriately changing visual
feedback to body movements. Because tendon vibration can affect our somatosensory perception, we
proposed a method for leveraging tendon vibration to extend pseudo-haptics [22]. To evaluate the
proposed method, we conducted three experiments that investigate the effect of tendon vibration on the
range and resolution of pseudo-haptic sensation (see figure 22). The first experiment evaluated the effect
of tendon vibration on the detection threshold (DT) of visual/physical motion discrepancy. The results
show that vibrations on the inner tendons of the wrist and elbow increased the DT. This indicates that
tendon vibration can increase applicable visual motion gain without being noticed by users. The second
experiment investigated the effect of tendon vibration on the resolution, that is, the just noticeable
difference (JND) of pseudo-weight sensation. The results indicate that both with-and without-vibration
conditions had a similar JND of pseudo-weight sensation and thus, both conditions can be considered to
have a similar resolution of sense of weight. The third experiment investigated the equivalence between
the weight sensation induced by tendon vibration and visual motion gain, that is, the point of subjective
equality (PSE). The results show that vibration increases the sense of weight, and its effect was the same as
that using a gain of 0.64 without vibration. Taken together, our results suggest that using tendon vibration
can enable a significantly wider (nearly double) range of pseudo-haptic sensation, without impairing its
resolution.

This work was done in collaboration with the University of Tokyo.

8.3.9 When tangibles become deformable: Studying pseudo-stiffness perceptual thresholds in a VR

grasping task

Participants:

Anatole Lécuyer (contact), Elodie Bouzbib.

Pseudo-Haptic techniques, or visuo-haptic illusions, leverage user’s visual dominance over haptics to
alter the users’ perception. As they create a discrepancy between virtual and physical interactions, these

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Figure 22: Apparatus used to assess the impact of tendon vibration on somatosensory perception: (a),
virtual environment (b), and wrist band with vibrators (c). Participants wore noise-cancelling headphones
during the experiment. In addition, the two target bars were not presented simultaneously but one-by-
one in each condition.

illusions are limited to a perceptual threshold. Many haptic properties have been studied using pseudo-
haptic techniques, such as weight, shape or size. In this work, we focus on estimating the perceptual
thresholds for pseudo-stiffness in a virtual reality grasping task [13]. We conducted a user study where
we estimated if compliance can be induced on a non-compressible tangible object and to what extent
(see figure 23). Our results show that (1) compliance can be induced in a rigid tangible object and that (2)
pseudo-haptics can simulate beyond 24 N/cm stiffness (between a gummy bear and a raisin, up to rigid
objects). Pseudo-stiffness efficiency is (3) enhanced by the objects’ scales, but mostly (4) correlated to the
user input force. Taken altogether, our results offer novel opportunities to simplify the design of future
haptic interfaces, and extend the haptic properties of passive props in VR.

This work was done in collaboration with Inria RAINBOW team.

8.4 Brain Computer Interfaces

8.4.1 Design and evaluation of vibrotactile stimulus to support a KMI-based neurofeedback

Participants:

Anatole Lécuyer (contact), Gabriela Altamira.

In this work [31], we are developing a brain-computer interface integrating visual and vibrotactile
feedback on the forearm and the hand in a gamified virtual environment to give situated and embodied
information about the quality of stroke patients’ kinesthetic motor imagery (KMI) of a grasping movement
(see figure 24). Multimodal sensory stimuli are used to provide a sense of embodiment. Particularly,
adding vibrotactile feedback is expected to improve the performance of a motor imagery task in neur-
otypical and stroke participants. A related publication [32] describes the multisensory stimuli used to

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Figure 23: When Tangibles Become Deformable: In the virtual environment, objects are displayed before
and after being compressed, following a compliance-stiffness continuum (sponge, tomato, matchbox,
water bottle, lock). In the real environment, a user is compressing a tangible object. Using pseudo-
stiffness, she perceives this same range of stiffness, while only grasping a noncompressible object. We
investigate the range of compliance and stiffness that can be elicited on a non-compressible tangible
object.

provide a sense of embodiment.

Figure 24: The GRASP-IT approach for BCI and post-stroke rehabilitation: three vibrotactile motors are
located on the hand and the forearm. Their activation rotation frequencies and duration are synchronized
and analogous to the visual feedback corresponding to four different levels of a grasping movement.

This work was done in collaboration with LORIA and Univ. Lorraine.

8.4.2 Which sensations should you imagine?

Participants:

François Le Jeune, Emile Savalle, Léa Pillette (contact).

During motor imagery-based brain computer interfaces (MI-BCI) training, users are most often
instructed to perform kinesthetic motor imagery, i.e., imagine the sensations related to a movement
[1]. However, there is a great variety of sensations associated with motor imagery that can either be

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interoceptive or exteroceptive [2]. Interoceptive sensations related to movement arise from within
the body, such as muscle contraction, whereas exteroceptive sensations are sensed through the skin,
such as touch or vibration. Among those different sensations, we do not know which to advise MI-BCI
users to imagine. Thus, our experiment [44] aims at studying the influence of imagining sensations on
neurophysiological activity and user experience.

8.4.3 Measuring presence in a virtual environment using electroencephalography: A study of breaks

in presence using an oddball paradigm

Participants:

Emile Savalle, Léa Pillette, Ferran Argelaguet, Léa Pillette,
Anatole Lécuyer, Kyung-Ho Won, Marc Macé (contact).

Presence is one of the main factor conditioning the user-experience in virtual reality (VR). It corres-
ponds to the illusion of being physically located in a virtual environment. Presence is usually measured
subjectively through questionnaires. However, questionnaires cannot be filled in when the user is experi-
encing presence, as it would disrupt the feeling. The use of electroencephalography (EEG) to monitor
users while they are immersed in VR presents an opportunity to bridge this gap and assess presence con-
tinuously. This study [47] aims at investigating whether different levels of presence can be distinguished
from EEG signals (see figure 25). Investigating further, we also tried to classify single trials according to
the level of presence in VR [45].

Figure 25: Concept picture representing the experimental protocol used in the experiment. We used an
oddball paradigm, represented as musical notes, to measure presence by studying the attention allocated
towards the real environment. Presence was manipulated using breaks in presence, during which the
participants could see their surroundings through the virtual headset. These breaks are represented with
the crack in the virtual environment showing a picture of the real experimental environment and setup.

8.4.4 Acceptability of BCI-based procedures for motor rehabilitation after stroke: A questionnaire

study among patients

Participants:

Léa Pillette (contact).

Stroke leaves around 40% of surviving patients dependent in their activities, notably due to severe
motor disabilities. BCIs have been shown to favour motor recovery after stroke, but this efficiency has not
reached yet the level required to achieve a clinical usage. We hypothesise that improving BCI acceptability,

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notably by personalising BCI-based rehabilitation procedures to each patient, will reduce anxiety and
favour engagement in the rehabilitation process, thereby increasing the efficiency of those procedures.
To test this hypothesis, we need to understand how to adapt BCI procedures to each patient depending
on their profile. Thus, we constructed a model of BCI acceptability [43] based on the literature, adapted it
in a questionnaire, and distributed the latter to post-stroke patients (N=140). Several articles related to
this online tool have been published [42, 50, 37]

This work was done in collaboration with INCIA (Bordeaux), CLLE and ICHN (Toulouse) and CRISTAL

(Lille).

8.4.5 A large EEG database with users’ profile information for motor imagery brain-computer inter-

face research

Participants:

Léa Pillette (contact).

In this work [17], we present and share a large database containing electroencephalographic signals
from 87 human participants, collected during a single day of brain-computer interface (BCI) experiments,
organized into 3 datasets (A, B, and C) that were all recorded using the same protocol: right and left hand
motor imagery (MI). Each session contains 240 trials (120 per class), which represents more than 20,800
trials, or approximately 70 hours of recording time. It includes the performance of the associated BCI
users, detailed information about the demographics, personality profile as well as some cognitive traits
and the experimental instructions and codes (executed in the open-source platform OpenViBE). Such
database could prove useful for various studies, including but not limited to: (1) studying the relationships
between BCI users’ profiles and their BCI performances, (2) studying how EEG signals properties varies
for different users’ profiles and MI tasks, (3) using the large number of participants to design cross-user
BCI machine learning algorithms or (4) incorporating users’ profile information into the design of EEG
signal classification algorithms. The content of this EEG database is also described in this article [49] (see
figure 26).

This work was done in collaboration with Inria POTIOC team (Bordeaux).

8.4.6 Does gender matter in motor imagery BCIs?

Participants:

Léa Pillette (contact).

A major issue in application of Motor Imagery Brain-computer interfaces (MI-BCI) is BCI inefficiency,
which affects 15-30% of the population. Several studies have tried to examine the effect of gender on
MI-BCI performance, however the reports remain inconsistent due to small sample sizes and unequal
gender distribution in past research. Hence, this study [48] aimed to address this gap by collecting a large
sample of female and male BCI users and investigating the role of gender in MI-BCIs in a reliable and
generalizable manner.

This work was done in collaboration with Tilburg University (Netherlands) and Inria POTIOC team

(Bordeaux).

8.5 Art and Cultural Heritage

8.5.1 Virtual Reality for the preservation and promotion of historical real tennis

Participants:

Ronan Gaugne (contact), Sony Saint-Auret, Valérie Gouranton.

Real tennis or “courte paume" in its original naming in French, is a racket sport that has been played
for centuries and is considered the ancestor of tennis. It was a very popular sport in Europe during the

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Figure 26: Final database structure, files, and naming.

Renaissance period, practiced in every layer of the society. It is still practiced today in few courts in the
world, especially in United Kingdom, France, Australia, and USA. It has been listed in the Inventory of
Intangible Cultural Heritage in France since 2012. The goal of our project [33] was to elicit interest in
this historical sport and for the new and future generations to experience it. We developed a virtual
environment that enables its users to experience real tennis game (see figure 27). This environment was
then tested to assess its acceptability and usability in different context of use. We found that such use of
virtual reality enabled our participants to discover the history and rules of this sport, in a didactic and
pleasant manner. We hope that our VR application will encourage younger and future generations to play
real tennis.

8.5.2 De l’imagerie médicale à la réalité virtuelle pour l’archéologie

Participants:

Ronan Gaugne, Bruno Arnaldi, Valérie Gouranton (contact).

In this book chapter, we describe the IRMA project [46] which aims to design innovative method-
ologies for research in the field of historical and archaeological heritage based on a combination of
medical imaging technologies and interactive 3D restitution modalities (virtual reality, augmented reality,
haptics, additive manufacturing) (see figure 28). These tools are based on recent research results from a
collaboration between IRISA, Inrap and the company Image ET and are intended for cultural heritage
professionals such as museums, curators, restorers and archaeologists.

This work was done in collaboration with INRAP institute, Trajectoires team (Paris) and Image ET

company.

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Figure 27: Player’s view in the virtual recreation of real tennis (“courte paume").

Figure 28: Left: A fibula extracted from an ancient urn and its 3D printed copy. Right: Full transparency
print of the urn.

9 Bilateral contracts and grants with industry

9.1 Grants with Industry

Nemo.AI Laboratory with InterDigital

Participants:

Ferran Argelaguet (contact), Anatole Lécuyer, Yann Glemarrec,
Tom Roy, Philippe Clermont de Gallerande.

To engage and employ scientists and engineers across the Brittany region in researching the technolo-
gies that will shape the metaverse, Inria, the French National Institute for Research in Digital Science and
Technology, and InterDigital, Inc. (NASDAQ:IDCC), a mobile and video technology research and develop-
ment company, launched the Nemo.AI Common Lab. This public-private partnership is dedicated to
leveraging the combined research expertise of Inria and InterDigital labs to foster local participation in
emerging innovations and global technology trends. Named after the pioneering Captain Nemo from
Jules Verne’s 20,000 Leagues Under the Sea, the Nemo.AI Common Lab aims to equip the Brittany region
with resources to pursue cutting edge scientific research and explore the technologies that will define
media experiences in the future. The project reflects the recognized importance of artificial intelligence
(AI) in enabling new media experiences in a digital and responsible society.

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Orange Labs

Inria Annual Report 2023

Participants:

Lysa Gramoli, Bruno Arnaldi, Valérie Gouranton (contact).

This grant started in October 2020. It supported Lysa Gramoli’s PhD program with Orange Labs

company on “Simulation of autonomous agents in connected virtual environments”.

Sogea Bretagne

Participants:

Vincent Goupil, Bruno Arnaldi, Valérie Gouranton (contact).

This grant started in October 2020. It supported Vincent Goupil’s CIFRE PhD program with Sogea

Bretagne company on “Hospital 2.0: Generation of Virtual Reality Applications by BIM Extraction”.

10 Partnerships and cooperations

10.1 European initiatives

10.1.1 H2020 projects

GuestXR GuestXR project on cordis.europa.eu

Title: GuestXR: A Machine Learning Agent for Social Harmony in eXtended Reality

Duration: From January 1, 2022 to December 31, 2025

Partners:

• INSTITUT NATIONAL DE RECHERCHE EN INFORMATIQUE ET AUTOMATIQUE (INRIA),

France

• UNIWERSYTET WARSZAWSKI (UNIWARSAW), Poland

• VIRTUAL BODYWORKS SL (Virtual Bodyworks S.L.), Spain

• UNIVERSITEIT MAASTRICHT, Netherlands

• UNIVERSITAT DE BARCELONA (UB), Spain

• FUNDACIO EURECAT (EURECAT), Spain

• REICHMAN UNIVERSITY (REICHMAN UNIVERSITY), Israel

• CENTRE NATIONAL DE LA RECHERCHE SCIENTIFIQUE CNRS (CNRS), France

• G.TEC MEDICAL ENGINEERING GMBH (G.TEC MEDICAL ENGINEERING GMBH), Austria

Inria contact: Anatole Lécuyer

Coordinator:

Summary: Immersive online social spaces will soon become ubiquitous. However, there is also a warning

that we need to heed from social media.

User content is the ‘lifeblood of social media’. However, it often stimulates antisocial interaction
and abuse, ultimately posing a danger to vulnerable adults, teenagers, and children.

In the VR space this is backed up by the experience of current virtual shared spaces. While they
have many positive aspects, they have also become a space full of abuse.

Our vision is to develop GuestXR, a socially interactive multisensory platform system that uses
eXtended Reality (virtual and augmented reality) as the medium to bring people together for
immersive, synchronous face-to-face interaction with positive social outcomes.

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The critical innovation is the intervention of artificial agents that learn over time to help the virtual
social gathering realise its aims. This is an agent that we refer to as “The Guest” that exploits
Machine Learning to learn how to facilitate the meeting towards specific outcomes.

Underpinning this is neuroscience and social psychology research on group behaviour, which will
deliver rules to Agent Based Models (ABM).

The combination of AI with immersive systems (including haptics and immersive audio), virtual
and augmented reality will be a hugely challenging research task, given the vagaries of social
meetings and individual behaviour. Several proof of concept applications will be developed during
the project, including a conflict resolution application in collaboration with the UN. A strong
User Group made up of a diverse range of stakeholders from industry, academia, government and
broader society will provide continuous feedback. An Open Call will be held to bring in artistic
support and additional use cases from wider society. Significant work is dedicated to ethics “by
design”, to identify problems and look eventually towards an appropriate regulatory framework for
such socially interactive systems.

10.1.2 Other european programs/initiatives

CHIST-ERA project - GENESIS

Genesis project on chistera.eu website

Title: LeveraGing nEuromarkers for Next-gEn immerSIve Systems

Duration: From January 1, 2022 to December 31, 2024

Partners:

• Inria (France)

• CRISTAL (France)

• ETH Zurich (Switzerland)

• Koç University (Turkey)

Inria contact: Anatole Lécuyer

Coordinator: Centre de Recherche en Informatique, Signal et Automatique de Lille - France

Summary: Brain-Computer Interfaces (BCIs) enable the leveraging of cerebral activity of users in order
to interact with computer systems. Originally designed for assisting motor-impaired people, a new
trend is emerging towards the use of BCI for a larger audience using passive BCI systems, which
are able to transparently provide information regarding the users’ mental states. Virtual Reality
(VR) technology could largely benefit from inputs provided by passive BCIs. VR enables to immerse
users in 3D computer-generated environments, in a way to make them feel present in the virtual
space, allowing through complete control of the environment, to offer several applications ranging
from training and education, to social networking and entertainment. Given the growing interest
of society and major industrial groups’ investments, VR is considered as a major revolution in
Human-Computer Interaction. However, to this day, VR has not yet reached its predicted level
of democratization and largely remains at the state of an entertaining experiment. This can be
explained by the difficulty to characterize users’ mental state during interaction and the inherent
lack of adaptation in the presentation of the virtual content. In fact, studies have shown that users
experience VR in different ways. While approximately 60% of users experience “cybersickness”,
which represents the set of deleterious symptoms that may occur after a prolonged use of virtual
reality systems, users can also suffer from breaks in presence and immersion, due to rendering and
interaction anomalies which can lead to a poor feeling of embodiment and incarnation towards
their virtual avatars. In both cases user’s experience is severely impacted as VR experience strongly
relies on the concepts of telepresence and immersion. The aim of this project is to pave the way to
the new generation of VR systems leveraging the electrophysiological activity of the brain through
a passive BCI to level-up the immersion in virtual environments. The objective is to provide VR

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Inria Annual Report 2023

systems with means to evaluate the users’ mental states through the real-time classification of EEG
data. This will improve users’ immersion in VR by reducing or preventing cybersickness, and by
increasing levels of embodiment through the real time adaptation of the virtual content to the
users’ mental states as provided by the BCI. In order to reach this objective, the proposed methodo-
logy is to (i) investigate neurophysiological markers associated with early signs of cybersickness,
as well as neuromarkers associated with the occurrence of VR anomalies; (ii) build on existing
signal processing methods for the real-time classification of these markers associating them with
corresponding mental states and (iii) provide mechanisms for the adaptation of the virtual content
to the estimated mental states.

10.2 National initiatives

10.2.1 ANR
ANR GRASP-IT

Participants:

Anatole Lécuyer (contact), Mélanie Cogné, Salomé Lefranc.

Duration: 2020 - 2024

Coordinator: LORIA

Partners: Inria Rennes (Hybrid), Inria Sophia, PErSEUs, CHU Rennes, CHU Toulouse, IRR UGECAM-N,

and Alchimies.

Summary: The GRASP-IT project aims to recover upper limb control improving the kinesthetic motor
imagery (KMI) generation of post-stroke patients using a tangible and haptic interface within a
gamified Brain-Computer Interface (BCI) training environment. This innovative KMI-based BCI
will integrate complementary modalities of interactions such as tangible and haptic interactions in
a 3D printable flexible orthosis. We propose to design and test usability (including efficacy towards
the stimulation of the motor cortex) and acceptability of this multimodal BCI. The GRASP-IT project
also proposes to design and integrate a gamified non-immersive virtual environment to interact
with. This multimodal solution should provide a more meaningful, engaging and compelling stroke
rehabilitation training program based on KMI production. In the end, the project will integrate and
evaluate neurofeedbacks, within the gamified multimodal BCI in an ambitious clinical evaluation
with 75 hemiplegic patients in 3 different rehabilitation centers in France.

10.2.2 PIA
PIA4 DemoES AIR

Participants:

INSA Rennes), Bruno Arnaldi,
Valérie Gouranton (contact, resp.
Ronan Gaugne, Florian Nouviale, Alexandre Audinot, Lysa Gramoli,
Tangui Marchand-Guerniou, Adrien Reuzeau, Mathieu Risy.

Duration: 12/2021 - 09/2025

Coordinator: Université Rennes

Partners: INSA Rennes, Université Rennes, Artefacto, Klaxoon

Project HYBRID

37

Description: The project Augmenter les Interactions à Rennes (AIR) is one of the 17 laureates chosen
by the French government as part of the call for expressions of interest “Digital demonstrators
in higher education” (DemoES) launched by the Ministry. of Higher Education, Research and
Innovation. Designed to overcome the artificial opposition between social learning and digital, the
AIR project is structured around 3 complementary axes:

• An augmented campus to facilitate social interactions across all activities (training, services,
exchanges and social relations) and ensure their continuum as an extension of physical
campuses, implemented in partnership with Orange Labs, a member of the consortium, with
the support for other EdTech players such as Appscho or Jalios.

• Interactive pedagogies to increase interactions in training and optimize, through interactivity,
learning, ranging from the development of serious games to the use of immersive technologies
(virtual reality, augmented reality, mixed reality), by developing functionalities resulting from
projects research carried out within the Hybrid team, in Irisa, by intensifying the partnership
established since 2018 with Klaxoon or by relying on Artefacto’s immersive solutions.

• An ecosystem of support for pedagogical and digital transformations to promote the appropri-
ation by teachers of these new large-scale devices, in particular thanks to the time allocated
dedicated to these transformations and to offer a recomposed and plural proximity assistance
to teaching teams.

PIA4 Equipex+ Continuum

Participants:

Ronan Gaugne (contact), Valérie Gouranton, Florian Nouviale.

Duration: 06/2021 - 05/2028

Coordinator: CNRS

Description: CONTINUUM is an 8 years EquipEx + project led by the CNRS as part of the 4th Future
Investments Program (PIA4). Endowed with € 13.6M, the project will create a collaborative research
infrastructure of 30 platforms located throughout France, in order to advance interdisciplinary
research between IT and the human and social sciences. Through CONTINUUM, 37 research
teams will develop cutting-edge research focused on visualization, immersion, interaction and
collaboration, as well as human perception, cognition and behavior in virtual augmented reality.
CONTINUUM is organized along two axes:

1. Interdisciplinary research on the interaction, in collaboration between computing and hu-
man and social sciences, in order to increase knowledge and solutions in human-centered
computing;

2. Deployment of tools and services to meet the needs of many scientific fields in terms of
access to big data, simulations and virtual / augmented experiences (mathematics, physics,
biology, engineering, computer science, medicine, psychology, didactics, history , archeology,
sociology, etc.)

By developing the instrument itself and using it in different fields of application, CONTINUUM will
promote interdisciplinary research in order to better understand how to interact with the digital
world and to enable advances in other fields of science and technology. ’engineering.

10.2.3 Inria projects

Inria Challenge NAVISCOPE

Participants:

Ferran Argelaguet (contact), Gwendal Fouché.

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Inria Annual Report 2023

Duration: 2019 - 2023

Coordinator: Serpico

Partners: Aviz, Beagle, Hybrid, Mosaic, Parietal, Morpheme

External partners: INRA and Institute Curie

Description: NAVISCOPE aims at improving visualization and machine learning methods in order to
provide systems capable to assist the scientist to obtain a better understanding of massive amounts
of information.

URL: NAVISCOPE

Inria Covid-19 Project VERARE

Participants: Mélanie Cogné (contact), Anatole Lécuyer,

Justine Saint-
Aubert, Valérie Gouranton, Ferran Argelaguet, Florian Nouviale,
Ronan Gaugne.

Duration: 2020 - 2024

Coordinator: Hybrid

External partners: University Hospital of Rennes

Description: VERARE (Virtual Environments for Rehabilitation After REsuscitation) is a multi-year
research project funded by Inria (specific Inria Covid-19 call for projects) for assessing the efficacy
of using Virtual Reality for motor rehabilitation (improving walk recovery) after resuscitation.
This ambitious clinical project gathers Hybrid team, federating 18 members of the team, and the
University Hospital of Rennes (Physical and Rehabilitation Medicine Unit and Intensive Care Units).

URL: VERARE

10.3 Regional initiatives

Rennes Métropole, “Créativite Croisée”, the secret of Bastet

Participants:

Valérie Gouranton (contact), Ronan Gaugne, Florian Nouviale, Ad-
rien Reuzeau.

Duration: 2022-2024
Coordinator: INSA Rennes
Partners: Université Rennes 1, Inrap, UMR Trajectoires,Musée des Beaux-arts de Rennes, Orange Labs,

Polymporph

Description: The project “The Secret of Bastet” aims to enrich the museography of the Egyptological
section of theMusée des Beaux-arts de Rennes by integrating an innovative museographic device of Virtual
Reality allowing a better understanding of the archaeological object for the general public. More precisely,
our approach is original because it will allow the visitor to access the scientific content reserved until
now to the experts, to experiment the process of the scientific approach by discovering the new digital
techniques of exploration and this in a playful, educational, immersive and interactive way, without
harming the individual emotion. For this project, the device will relate the museum’s objects from
the collection of Egyptian animal mummies and specifically one of the museum’s flagship works, the
CatMummy as well as its transparent 3D printing replica from a previous project.

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11 Dissemination

11.1 Promoting scientific activities

11.1.1 Scientific events: organisation

Member of the organizing committees

• Anatole Lécuyer is member of the steering committee of IEEE VR Conference.

• Guillaume Moreau is member of the steering committee of IEEE ISMAR Conference.

11.1.2 Scientific events: selection

• Anatole Lécuyer organized a seminar on "Virtual Reality and Metaverse" at Okinawa Institute of

Science and Technology, Japan.

Chair of conference program committees

• Ferran Argelaguet was Program Chair of the ACM Symposium on Spatial User Interfaces 2023.

• Guillaume Moreau was Program Chair for the Journal Track of IEEE ISMAR 2023.

• Jean-Marie Normand was Program Chair of ICAT-EGVE 2023, the joint 33rd International Con-
ference on Artificial Reality and Telexistence & the 28th Eurographics Symposium on Virtual
Environments.

Member of the conference program committees

• Ferran Argelaguet was member of the IEEE Virtual Reality and 3D User Interfaces (VR) 2023 IPC.

• Rebecca Fribourg was member of the IPC for IEEE International Symposium on Mixed and Aug-
mented Reality (ISMAR) 2023 and for ICAT-EGVE 2023, the joint 33rd International Conference on
Artificial Reality and Telexistence & the 28th Eurographics Symposium on Virtual Environments.

• Jean-Marie Normand was member of the IPC for IEEE Virtual Reality and 3D User Interfaces (VR)
2023 and for IEEE International Symposium on Mixed and Augmented Reality (ISMAR) 2023 Journal
Track.

Reviewer (conferences)

• Ferran Argelaguet was reviewer for ACM Virtual Reality Software and Technology (VRST) 2023 and

IEEE International Symposium on Mixed and Augmented Reality (ISMAR) 2023.

• Rebecca Fribourg was reviewer for IEEE VR 2023 and IEEE VR 2023.

• Marc Macé was reviewer for IEEE VR 2023 and ISMAR 2023.

• Guillaume Moreau was reviewer for IEEE ISMAR 2023, IEEE VR 2023 and ICAT-EGVE 2023.

• Léa Pillette was a reviewer for BCI conference 2023, ISMAR 2023 and CORTICO 2023.

11.1.3 Journal

Member of editorial boards

• Anatole Lécuyer is member of the editorial board of Presence and Frontiers in Virtual Reality

journals.

• Ferran Argelaguet is member of the editorial board of ERCIM News.

• Valérie Gouranton is member of the editorial board of Frontiers in Virtual Reality journals.

• Jean-Marie Normand is Associate Editor for IEEE Transactions on Visualization and Computer
Graphics (TVCG) and member of the editorial board of the Frontiers in Virtual Reality journal.

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Inria Annual Report 2023

Reviewer (journals)

• Ferran Argelaguet was reviewer for IEEE TVCG, ACM TAP and IEEE ToH.

• Marc Macé was reviewer for IEEE TOH.

• Léa Pillette was reviewer for Brain Sciences, Computer Modelling in Engineering & Sciences,
Frontiers in Neuroscience, Frontiers in Human Neuroscience, Journal of Neural Engineering,
Medicina, PRESENCE: Virtual and Augmented Reality.

11.1.4 Invited talks

• Anatole Lécuyer gave invited talks at NAIST (Nara, May 2023), OIST (Okinawa, May 2023), and

Tokyo University (May 2023).

• Ferran Argelaguet was an invited keynote speaker for the VISIGRAPP 2023 conference (Lisbon,

Portugal) and for the EuroXR conference 2023 (Rotterdam, Netherlands).

• Mélanie Cogné gave invited talks at ECNR (Lyon, Sept. 2023) and SOFMER 2023 (Le Havre, Oct.

2023) conferences.

• Guillaume Moreau gave invited talls at Tokyo University and OIST (Okinawa).

• Léa Pillette gave invited talks at Tokyo University (Tokyo, March 2023), Keio University (Tokyo,
March 2023), RIKEN (Tokyo, March 2023), OIST (Okinawa, March 2023), g.tec BCI Neurotech
Masterclass France (virtual event, November 2023) and 2nd Workshop on Artificial Intelligence for
Human Machine Interaction AIxHMI 2023 (Rome, November 2023).

• Rebecca Fribourg gave invited talks at Tokyo University (Tokyo, March 2023), Keio University (Tokyo,
March 2023), RIKEN (Tokyo, March 2023), OIST (Okinawa, March 2023), at EPFL in Ronan Boulic
team (Lausanne, June 2023), and in GV2 group at TCD (Dublin, December 2023).

11.1.5 Leadership within the scientific community

• Valérie Gouranton is a Member of the Consortium 3D of TGIR HumaNum.

• Guillaume Moreau is member of the PEPR Ensemble Valorisation board.

• Jean-Marie Normand is co-head of the "Groupe de Travail Réalités Virtuelles" (GT-RV) of the
Groupement de Recherche Informatique Géométrique et Graphique, Réalité Virtuelle et visualisa-
tion (GdR IG-RV).

• Léa Pillette joined the board of the national BCI association (CORTICO).

11.1.6 Scientific expertise

• Valérie Gouranton was a member of the Conseil National des Universités 27th section (computer

science), and ANR committee "factory of the future".

• Guillaume Moreau is member of the scientific council of IBISC lab and ENSIEE.

11.1.7 Research administration

• Anatole Lécuyer is member of the steering committee of IEEE VR conference.

• Ferran Argelaguet is member of the scientific committee of the EUR Digisport and the EquipEx+

Continuum.

• Marc Macé is member of the competitivity cluster Images & networks

• Guillaume Moreau is Deputy Dean for Research and Innovation of IMT Atlantique

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41

11.2 Teaching - Supervision - Juries

11.2.1 Teaching

In this section, only courses related to the main research field of Hybrid are listed.
Anatole Lécuyer:

• Master AI-ViC: “Haptic Interaction and Brain-Computer Interfaces”, 6h, M2, Ecole Polytechnique,

FR

• Master MNRV: “Haptic Interaction”, 9h, M2, ENSAM, Laval, FR

• Master SIBM: “Haptic and Brain-Computer Interfaces”, 4.5h, M2, University of Rennes 1, FR

• Master SIF: “Pseudo-Haptics and Brain-Computer Interfaces”, 6h, M2, INSA Rennes, FR

Ferran Argelaguet:

• Master STS Informatique: “Techniques d’Interaction Avancées”, 26h, M2, ISTIC, University of

Rennes 1, FR

• Master SIF: “Virtual Reality and Multi-Sensory Interaction”, 8h, M2, INSA Rennes, FR

• Master SIF: “Data Mining and Visualization”, 2h, M2, University of Rennes 1, FR

• Master AI-ViC: “Virtual Reality and 3D Interaction”, 3h, M2, École Polytechnique, FR

Valérie Gouranton:

• Licence: Project on “Virtual Reality”, 28h, L3, responsible of this lecture, INSA Rennes, FR

• Master INSA Rennes: “Virtual Reality”, 22h, M2, INSA Rennes, FR

• Master INSA Rennes: Projects on “Virtual Reality”, 60h, M1, INSA Rennes, FR

• Master CN: “Virtual Reality”, 3h, M1, University of Rennes 2, FR

• Responsible for international relations, INSA Rennes, Computer science department

Ronan Gaugne:

• INSA Rennes: Projects on “Virtual Reality”, 24h, L3, INSA Rennes, FR

• Master Digital Creation: “Virtual Reality”, 6h, M1, University of Rennes 2, FR

Jean-Marie Normand:

• Virtual Reality Major, “Computer Graphics”, 24h, M1/M2, École Centrale de Nantes, FR

• Virtual Reality Major, “Fundamentals of Virtual Reality”, 20h, M1/M2, École Centrale de Nantes, FR

• Virtual Reality Major, “Computer Vision and Augmented Reality”, 25h, M1/M2, École Centrale de

Nantes, FR

• Virtual Reality Major, “Advanced Concepts in VR/AR”, 24h, M1/M2, École Centrale de Nantes, FR

• Virtual Reality Major, “Projects on Virtual Reality”, 20h, M1/M2, École Centrale de Nantes, FR

• Master MTI3D: “Virtual Embodiment”, 3h, M2, ENSAM Laval, FR

Rebecca Fribourg:

• Virtual Reality Major, “C++ Programming for VR”, 20h, M1/M2, École Centrale de Nantes, FR

• Virtual Reality Major, “Fundamentals of Virtual Reality”, 7h, M1/M2, École Centrale de Nantes, FR

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Inria Annual Report 2023

• Virtual Reality Major, “Advanced Concepts in VR/AR”, 16h, M1/M2, École Centrale de Nantes, FR

• Virtual Reality Major, “Projects on Virtual Reality”, 15h, M1/M2, École Centrale de Nantes, FR

• Virtual Reality Major, “Projects in OpenGL C++”, 10h, M1/M2, École Centrale de Nantes, FR

• Virtual Reality Major, “Immersive Data Visualization”, 12h, M1/M2, École Centrale de Nantes, FR

Léa Pillette:

• Master SIBM: “Haptic and Brain-Computer Interfaces”, 4.5h, M2, University of Rennes 1, FR

• Master students: “Brain-Computer Interfaces”, 4h, M2, IMT Atlanique, Brest, FR

11.2.2 Supervision

• PhD: Grégoire Richard, “Rôle du retour haptique dans les interactions avec des avatars en réalité
virtuelle”, Defended in June 2023, Supervised by Géry Casiez (Loki, Inria), Thomas Pietzrak (Loki,
Inria), Anatole Lécuyer and Ferran Argelaguet.

• PhD: Martin Guy, “Physiological markers for characterizing virtual embodiment”, Defended in
February 2023, Supervised by Guillaume Moreau (IMT Atlantique), Jean-Marie Normand (ECN)
and Camille Jeunet (CNRS, INCIA).

• PhD: Lysa Gramoli, “Simulation of autonomous agents in connected virtual environments”, Defen-
ded in September 2023, Supervised by Valérie Gouranton, Bruno Arnaldi, Jérémy Lacoche (Orange),
Anthony Foulonneau (Orange).

• PhD: Vincent Goupil, “Model and algorithm for designing complex building signage in virtual
reality”, Defended in November 2023, Supervised by Valérie Gouranton, Bruno Arnaldi, Anne-
Solène Michaud (Vinci Construction).

• PhD: Gabriela Herrera Altamira, “Neurofeefdback based on VR and haptics”, Defended in January

2024. Supervised by Laurent Bougrain (LORIA), Stéphanie Fleck (Univ. Lorraine), and Anatole Lécuyer.

• PhD: Maé Mavromatis, “Towards Avatar-Friendly Interaction techniques in VR”, PhD stopped in
March 2023, Supervised by Anatole Lécuyer, Ferran Argelaguet and Ludovic Hoyet (MimeTIC, Inria).

• PhD in progress (CIFRE): Nicolas Fourrier “Collaborative and interactive ship outfitting in virtual
reality”, Started in May 2021, Supervised by Jean-Marie Normand, Guillaume Moreau and Mustaph
Benaouicha (Segula Technologies) in collaboration with Segula Technologies.

• PhD in progress: Antonin Cheymol, “Body-based Interfaces in Mixed Reality for Urban Applica-
tions”, Started in November 2021, Supervised by Anatole Lécuyer, Ferran Argelaguet, Jean-Marie Nor-
mand (ECN) and Rebecca Fribourg (ECN).

• PhD in progress: Yann Moullec, “Walking Sensations in VR”, Started in October 2021, Supervised by

Anatole Lécuyer and Mélanie Cogné.

• PhD in progress: Emilie Hummel, “Rehabilitation post-Cancer based on VR”, Started in October

2021, Supervised by Anatole Lécuyer, Valérie Gouranton and Mélanie Cogné.

• PhD in progress: Jeanne Hecquard, “Affective Haptics in Virtual Reality”, Started in October 2022,
Supervised by Marc Macé, Anatole Lécuyer, Ferran Argelaguet and Claudio Pacchierotti(Rainbow,
Inria).

• PhD in progress: Emile Savalle, “Cybersickness assessment in Virtual Reality using Neurophysiology”,
Started in October 2022, Supervised by Marc Macé, Anatole Lécuyer, Ferran Argelaguet and Léa Pil-
lette.

• PhD in progress: Mathieu Risy, “Pedagogical models in Virtual Reality training environments”,

Started in October 2022, Supervised by Valérie Gouranton.

Project HYBRID

43

• PhD in progress: Sony Saint-Auret, “Collaborative real tennis in virtual reality”, Started in Novem-
ber 2022, Supervised by Valérie Gouranton, Franck Multon and Richard Kulpa (Mimetic, Inria),
Ronan Gaugne.

• PhD in progress: Julien Lomet, “Cocreation of a virtual reality artwork, from the artist to the viewer”,
Started in October 2022, Supervised by Valérie Gouranton, Ronan Gaugne, Joêl Laurent (UR2),
Cédric Plessiet (Université Paris 8).

• PhD in progress (CIFRE): Philippe de Clermont de Gallerande, “Deep-based semantic representa-
tion of avatars for virtual reality”, Started in March 2023, Supervised by Ferran Argelaguet, Ludovic
Hoyet (Virtus) and in collaboration with InterDigital.

• PhD in progress (CIFRE): Tom Roy, “Modeling Kinesthetic an tactile properties of virtual envir-
onments”, Started in October 2023, Supervised by Ferran Argelaguet and in collaboration with
InterDigital.

• PhD in progress: Sabrina Toofany, “Etude de retour haptique pour encourager les interactions
sociales positives en réalité virtuelle”, Started in October 2023, Supervised by Anatole Lécuyer,
Ferran Argelaguet and Justine Saint-Aubert.

• PhD in progress: Maxime Dumonteil, “Perception of archaeological artefacts”, Started in October
2023, Supervided by Ronan Gaugne, Valérie Gouranton, Marc Macé and Théophane Nicolas (UMR
Trajectoires).

• PhD in progress: Romain Chabbert, “Virtual reality in non-Euclidean spaces”, Started in October

2023, Supervided by Valérie Gouranton, Ronan Gaugne and Rémi Coulon (UMR IMB).

• PhD in progress: Julien Manson, “Design of Haptic Interfaces for Supporting Social Interactions
in Virtual Reality”, PhD started in October 2023, Supervised by Anatole Lécuyer and Justine Saint-
Aubert.

• PhD in progress: Florence Celant, “Study of motor rehabilitation based on virtual reality interfaces”,
PhD started in November 2023, Supervised by Anatole Lécuyer, Mélanie Cogné and Isabelle Bonan
(CHU Rennes).

• PhD in progress: Clément Broutin, “Augmented Reality for Improving Autonomy in Dementia”,
Started in December 2023, Supervised by Jean-Marie Normand, Guillaume Moreau, Mélanie
Cogné and Anatole Lécuyer.

11.2.3 Juries

• Anatole Lécuyer was President of PhD Jury of Vincent Goupil (INSA Rennes), and of HDR Juries of

Olivier Christmann (ENSAM Laval) and Régis Lobjois (Univ. Gustave Eiffel).

• Rebecca Fribourg was examiner for the PhD thesis of Nana Tian (EPFL).

• Valérie Gouranton was reviewer of Gaëtan Henry (Université Paris 8) and Corentin Coupry (Uni-

versité d’Angers) PhD thesis and examiner for the PhD thesis of Raphaël James (Paris-Saclay).

• Jean-Marie Normand was member of HDR jury of Régis Lobjois (Univ. Gustave Eiffel).

• Léa Pillette was examiner for the PhD thesis of Tristan Venot (ICM Paris).

11.3 Popularization

11.3.1 Articles and contents

• "Ouest-France" newspaper: article on "Archeology and VR" (Valérie Gouranton), December 2023

• "Le Monde" newspaper: article on "Proteus effect" (Anatole Lécuyer), November 2023

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Inria Annual Report 2023

• "Epsiloon" magazine: article on "Proteus effect" (Anatole Lécuyer), November 2023

• "Science et Avenir" magazine: article on "Proteus effect" (Anatole Lécuyer), November 2023

• "RFI" radio: broadcast "Autour de La Question", interview on "Brain-Computer Interfaces" (Anatole Lécuyer),

September 2023

• "Ouest-France" newspaper: interview from Anatole Lécuyer, June 2023

• "Science et Vie Junior" magazine: article on Metaverse (Anatole Lécuyer), March 2023

• "Science Ouest" magazine: article on "Xareus" (Valérie Gouranton), January 2023

11.3.2 Interventions

Demos and webinars

• "VIVATECH" exhibition: demo from "Jeu de Paume" (Ronan Gaugne, Valérie Gouranton), July 2023

• "g.tec masterclass": on-line seminar on BCI and VR (Léa Pillette, Marc Macé), September 2023

• "Frontiers": webinar on “Haptics in Social Interactions” (Anatole Lécuyer), June 2023

• "Agence Régionale de Santé": webinar on "Long-lasting Covid" (Mélanie Cogné), May 2023

• "Nuit des Musées": demo from the team (Ronan Gaugne, Valérie Gouranton), May 2023

• "Laval Virtual 2023" exhibition: demos from the team, April 2023

• "EdTech Grand Ouest 2023": demo from Xareus (Florian Nouviale, Valérie Gouranton), March 2023

• "Techno-conference" on Metaverse: demos from the team (Ferran Argelaguet), March 2023

• "Made by" event: demo from Xareus (Florian Nouviale, Valérie Gouranton), February 2023

• "Journées Patrimoine": demos from the team, January 2023 (Valérie Gouranton, Ronan Gaugne)

12 Scientific production

12.1 Major publications

[1] X. De Tinguy, C. Pacchierotti, A. Lécuyer and M. Marchal. ‘Capacitive Sensing for Improving Contact
Rendering with Tangible Objects in VR’. In: IEEE Transactions on Visualization and Computer
Graphics (Jan. 2021). DOI: 10.1109/TVCG.2020.3047689. URL: https://hal.inria.fr/hal-0
3092809.

[2] M. Fleury, G. Lioi, C. Barillot and A. Lécuyer. ‘A Survey on the Use of Haptic Feedback for Brain-
Computer Interfaces and Neurofeedback’. In: Frontiers in Neuroscience 1 (June 2020). DOI: 10.338
9/fnins.2020.00528. URL: https://hal.archives-ouvertes.fr/hal-02459828.

[3] R. Fribourg, F. Argelaguet Sanz, A. Lécuyer and L. Hoyet. ‘Avatar and Sense of Embodiment: Studying
the Relative Preference Between Appearance, Control and Point of View’. In: IEEE Transactions on
Visualization and Computer Graphics 26.5 (May 2020), pp. 2062–2072. DOI: 10.1109/TVCG.2020
.2973077. URL: https://hal.inria.fr/hal-02868067.

[4] R. Gaugne, F. Labaune-Jean, D. Fontaine, G. Le Cloirec and V. Gouranton. ‘From the engraved tablet
to the digital tablet, history of a fifteenth century music score’. In: Journal on Computing and
Cultural Heritage 13.3 (2020), pp. 1–18. DOI: 10.1145/3383782. URL: https://hal.archives-o
uvertes.fr/hal-02574884.

[5] M. Guy, J.-M. Normand, C. Jeunet-Kelway and G. Moreau. ‘The sense of embodiment in Virtual
Reality and its assessment methods’. In: Frontiers in Virtual Reality 4 (2023), p. 1141683. DOI:
10.3389/frvir.2023.1141683. URL: https://hal.science/hal-04323074.

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[6] F. Lécuyer, V. Gouranton, A. Lamercerie, A. Reuzeau, B. Arnaldi and B. Caillaud. ‘Unveiling the
implicit knowledge, one scenario at a time’. In: Visual Computer (2020), pp. 1–12. DOI: 10.1007/s
00371-020-01904-7. URL: https://hal.inria.fr/hal-02879083.

[7] H. Si-Mohammed, J. Petit, C. Jeunet, F. Argelaguet Sanz, F. Spindler, A. Evain, N. Roussel, G. Casiez
and A. Lécuyer. ‘Towards BCI-based Interfaces for Augmented Reality: Feasibility, Design and Eval-
uation’. In: IEEE Transactions on Visualization and Computer Graphics 26.3 (Mar. 2020), pp. 1608–
1621. DOI: 10.1109/TVCG.2018.2873737. URL: https://hal.inria.fr/hal-01947344.

[8] Y. Moullec, M. Cogné, J. Saint-Aubert and A. Lécuyer. ‘Assisted walking-in-place: Introducing as-
sisted motion to walking-by-cycling in embodied virtual reality’. In: IEEE Transactions on Visualiza-
tion and Computer Graphics 29.5 (May 2023), pp. 2796–2805. DOI: 10.1109/TVCG.2023.3247070.
URL: https://insa-rennes.hal.science/hal-04135293.

[9] T. Nicolas, R. Gaugne, C. Tavernier, Q. Petit, V. Gouranton and B. Arnaldi. ‘Touching and interacting
with inaccessible cultural heritage’. In: Presence: Teleoperators and Virtual Environments 24.3 (2015),
pp. 265–277. DOI: 10.1162/pres_a_00233. URL: https://hal.inria.fr/hal-01218223.

[10] E. Peillard, Y. Itoh, J.-M. Normand, F. Argelaguet Sanz, G. Moreau and A. Lécuyer. ‘Can Retinal
Projection Displays Improve Spatial Perception in Augmented Reality?’ In: ISMAR 2020 - 19th IEEE
International Symposium on Mixed and Augmented Reality. 2020 IEEE International Symposium
on Mixed and Augmented Reality (ISMAR). Recife, Brazil: IEEE, Nov. 2020, pp. 124–133. DOI: 10.11
09/ISMAR50242.2020.00028. URL: https://hal.archives-ouvertes.fr/hal-02911740.

[11] E. Peillard, T. Thebaud, J.-M. Normand, F. Argelaguet Sanz, G. Moreau and A. Lécuyer. ‘Virtual
Objects Look Farther on the Sides: The Anisotropy of Distance Perception in Virtual Reality’. In:
VR 2019 - 26th IEEE Conference on Virtual Reality and 3D User Interfaces. Osaka, Japan: IEEE, Mar.
2019, pp. 227–236. DOI: 10.1109/VR.2019.8797826. URL: https://hal.archives-ouvertes
.fr/hal-02084069.

[12]

J. Saint-Aubert, F. Argelaguet, M. J.-M. Macé, C. Pacchierotti, A. Amedi and A. Lécuyer. ‘Persuasive
Vibrations: Effects of Speech-Based Vibrations on Persuasion, Leadership, and Co-Presence During
Verbal Communication in VR’. In: VR 2023 - IEEE Conference on Virtual Reality and 3D User
Interfaces. Shanghai, China: IEEE, 25th Mar. 2023, pp. 1–9. URL: https://inria.hal.science/h
al-03997713.

12.2 Publications of the year

International journals

[13] E. Bouzbib, C. Pacchierotti and A. Lécuyer. ‘When Tangibles Become Deformable: Studying Pseudo-
Stiffness Perceptual Thresholds in a VR Grasping Task’. In: IEEE Transactions on Visualization and
Computer Graphics 29.5 (8th Mar. 2023), pp. 2743–2752. DOI: 10.1109/TVCG.2023.3247083. URL:
https://inria.hal.science/hal-03997198.

[14] E. Bouzbib, M. Teyssier, T. Howard, C. Pacchierotti and A. Lecuyer. ‘PalmEx: Adding Palmar Force-
Feedback for 3D Manipulation with Haptic Exoskeleton Gloves’. In: IEEE Transactions on Visualiza-
tion and Computer Graphics (10th Feb. 2023), pp. 1–9. DOI: 10.1109/TVCG.2023.3244076. URL:
https://inria.hal.science/hal-03997349.

[15] A. Cheymol, R. Fribourg, A. Lécuyer, J.-M. Normand and F. Argelaguet. ‘Beyond my Real Body:
Characterization, Impacts, Applications and Perspectives of “Dissimilar” Avatars in Virtual Reality’.
In: IEEE Transactions on Visualization and Computer Graphics (16th Oct. 2023), pp. 1–12. URL:
https://inria.hal.science/hal-04216303.

[16] A. Costes and A. Lécuyer. ‘Inducing Self-Motion Sensations with Haptic Feedback: State-of-the-Art
and Perspectives on “Haptic Motion”’. In: IEEE Transactions on Haptics (ToH) (23rd May 2023),
pp. 1–11. DOI: 10.1109/TOH.2023.3279267. URL: https://inria.hal.science/hal-041142
41.

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[17] P. Dreyer, A. Roc, L. Pillette, S. Rimbert and F. Lotte. ‘A large EEG database with users’ profile
information for motor imagery brain-computer interface research’. In: Scientific Data 10.1 (Sept.
2023), p. 580. DOI: 10.1038/s41597-023-02445-z. URL: https://inria.hal.science/hal-0
4197139.

[18] G. Fouché, F. Argelaguet, E. Faure and C. Kervrann. ‘Immersive and interactive visualization of 3D
spatio-temporal data using a space time hypercube: Application to cell division and morphogenesis
analysis’. In: Frontiers in Bioinformatics 3 (8th Mar. 2023), pp. 1–13. DOI: 10.3389/fbinf.2023.9
98991. URL: https://inria.hal.science/hal-04112210.

[19] N. Fourrier, G. Moreau, M. Benaouicha and J.-M. Normand. ‘Handwriting for Efficient Text Entry in
Industrial VR Applications: Influence of Board Orientation and Sensory Feedback on Performance’.
In: IEEE Transactions on Visualization and Computer Graphics 29.11 (Nov. 2023), pp. 4438–4448.
DOI: 10.1109/TVCG.2023.3320215. URL: https://hal.science/hal-04304498.

[20] G. Gorisse, S. Wellenreiter, S. Fleury, A. Lécuyer, S. Richir and O. Christmann. ‘I am a Genius! Influ-
ence of Virtually Embodying Leonardo da Vinci on Creative Performance’. In: IEEE Transactions on
Visualization and Computer Graphics 29.11 (2023), pp. 4328–4338. DOI: 10.1109/TVCG.2023.332
0225. URL: https://hal.science/hal-04371690.

[21] M. Guy, J.-M. Normand, C. Jeunet-Kelway and G. Moreau. ‘The sense of embodiment in Virtual
Reality and its assessment methods’. In: Frontiers in Virtual Reality 4 (2023), p. 1141683. DOI:
10.3389/frvir.2023.1141683. URL: https://hal.science/hal-04323074.

[22] Y. Hirao, T. Amemiya, T. Narumi, F. Argelaguet and A. Lécuyer. ‘Leveraging Tendon Vibration to
Extend Pseudo-Haptic Sensations in VR’. In: IEEE Transactions on Visualization and Computer
Graphics (30th Aug. 2023), pp. 1–13. DOI: 10.1109/TVCG.2023.3310001. URL: https://inria.h
al.science/hal-04216297.

[23] E. Hummel, M. Cogné, M. Lange, A. Lécuyer, F. Joly and V. Gouranton. ‘VR for Vocational and
Ecological Rehabilitation of Patients With Cognitive Impairment: A Survey’. In: IEEE Transactions on
Neural Systems and Rehabilitation Engineering 31 (2023), pp. 4167–4178. DOI: 10.1109/TNSRE.20
23.3324131. URL: https://hal.science/hal-04341524.

[24] P. Kourtesis, R. Amir, J. Linnell, F. Argelaguet and S. Macpherson. ‘Cybersickness, Cognition, & Motor
Skills: The Effects of Music, Gender, and Gaming Experience’. In: IEEE Transactions on Visualization
and Computer Graphics (22nd Feb. 2023), pp. 1–11. DOI: 10.1109/TVCG.2023.3247062. URL:
https://hal.science/hal-04004668.

[25] P. Kourtesis, J. Linnell, R. Amir, F. Argelaguet and S. Macpherson. ‘Cybersickness in Virtual Reality
Questionnaire (CSQ-VR): A Validation and Comparison against SSQ and VRSQ’. In: Virtual Worlds
2.1 (Mar. 2023), pp. 16–35. DOI: 10.3390/virtualworlds2010002. URL: https://hal.science
/hal-03980050.

[26] M. Mavromatis, L. Hoyet, A. Lécuyer, D. Dewez and F. Argelaguet. ‘To Stick or Not to Stick? Studying
the Impact of Offset Recovery Techniques During Mid-Air Interactions’. In: IEEE Transactions on
Visualization and Computer Graphics (2023), pp. 1–14. DOI: 10.1109/tvcg.2023.3295209. URL:
https://inria.hal.science/hal-04214485.

[27] F. Morbidi, L. Devigne, C. S. Teodorescu, B. Fraudet, E. Leblong, T. Carlson, M. Babel, S. Delmas,
G. Caron, F. Pasteau, G. Vailland, V. Gouranton, S. Guegan, R. Le Breton and N. Ragot. ‘Assistive
Robotic Technologies for Next-Generation Smart Wheelchairs: Codesign and Modularity to Improve
Users’ Quality of Life’. In: IEEE Robotics and Automation Magazine 30.1 (Mar. 2023), pp. 24–35. DOI:
10.1109/MRA.2022.3178965. URL: https://hal.science/hal-03709574.

[28] Y. Moullec, M. Cogné, J. Saint-Aubert and A. Lécuyer. ‘Assisted walking-in-place: Introducing as-
sisted motion to walking-by-cycling in embodied virtual reality’. In: IEEE Transactions on Visualiza-
tion and Computer Graphics 29.5 (May 2023), pp. 2796–2805. DOI: 10.1109/TVCG.2023.3247070.
URL: https://insa-rennes.hal.science/hal-04135293.

[29] A. Verhulst, J.-M. Normand, G. Moreau and G. Patow. ‘Deep weathering effects’. In: Computers and
Graphics 112 (May 2023), pp. 40–49. DOI: 10.1016/j.cag.2023.03.006. URL: https://hal.sci
ence/hal-04056425.

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[30] S. Vizcay, P. Kourtesis, F. Argelaguet, C. Pacchierotti and M. Marchal. ‘Design, evaluation and
calibration of wearable electrotactile interfaces for enhancing contact information in virtual reality’.
In: Computers and Graphics (Feb. 2023), pp. 1–15. DOI: 10.1016/j.cag.2023.01.013. URL: http
s://inria.hal.science/hal-03991492.

International peer-reviewed conferences

[31] G. H. Altamira, S. Fleck, A. Lécuyer and L. Bougrain. ‘Design and Evaluation of Vibrotactile Stimulus
to Support a KMI-based Neurofeedback’. In: Proceedings of the 10th International Brain-Computer
Interface Meeting 2023. BCI 2023 - 10th International Brain-Computer Interface Meeting. La Hulpe,
Belgium, 2023, pp. 1–1. DOI: 10.3217/978-3-85125-962-9-108. URL: https://hal.science
/hal-04228934.

[32] G. H. Altamira, N. Skiba, A. Lécuyer, L. Bougrain and S. Fleck. ‘Multisensory neurofeedback design
for KMI embodiment’. In: IMX 2023 - ACM International Conference on Interactive Media Experi-
ences. Nantes, France, 2023, pp. 1–3. DOI: 10.1145/3604321.3604352. URL: https://hal.scie
nce/hal-04228939.

[33] R. Gaugne, S. Saint-Auret, P. Duc-Martin and V. Gouranton. ‘Virtual Reality for the Preservation and
Promotion of Historical Real Tennis’. In: Proceedings of Computer Graphics International. CGI 2023
- Computer Graphics International. Shangai, China, 2023, pp. 1–13. URL: https://hal.science
/hal-04211663.

[34] V. Goupil, B. Arnaldi, F. Argelaguet, A.-S. Michaud and V. Gouranton. ‘Can You Find Your Way?
Comparing Wayfinding Behaviour Between Reality and Virtual Reality’. In: ICAT-EGVE 2023 -
International Conference on Artificial Reality and Telexistence & Eurographics Symposium on
Virtual Environments. Dublin, Ireland, 2023, pp. 1–10. URL: https://hal.science/hal-043223
16.

[35]

J. Hecquard, J. Saint-Aubert, F. Argelaguet, C. Pacchierotti, A. Lécuyer and M. J.-M. Macé. ‘Fostering
empathy in social Virtual Reality through physiologically based affective haptic feedback’. In: WHC
2023 - IEEE World Haptics Conference. Delft, Netherlands, 10th July 2023. URL: https://hal.sci
ence/hal-04099268.

[36] R. Otono, A. Genay, M. Perusquía-Hernández, N. Isoyama, H. Uchiyama, M. Hachet, A. Lécuyer and
K. Kiyokawa. ‘I’m Transforming! Effects of Visual Transitions to Change of Avatar on the Sense of
Embodiment in AR’. In: 2023 IEEE Conference Virtual Reality and 3D User Interfaces (VR). VR 2023 -
IEEE Conference on Virtual Reality and 3D User Interfaces. Shanghai, China, Mar. 2023, pp. 83–93.
URL: https://inria.hal.science/hal-03968274.

[37] L. Pillette, E. Grevet, C. Dussard, F. Amadieu, D. Gasq, E. Pierrieau, J. Py, H. Si-Mohammed, N.
George and C. Jeunet-Kelway. ‘An online tool to facilitate the assessment of BCI acceptability’. In:
10th International BCI Meeting. BCI 2023 - 10th International BCI Meeting Balancing Innovation
and Translation. Abstract Book. Bruxelles, Belgium, 6th June 2023, pp. 1–1. URL: https://hal.sc
ience/hal-04289425.

[38] G. Richard, T. Pietrzak, F. Argelaguet, A. Lécuyer and G. Casiez. ‘MultiVibes: What if your VR
Controller had 10 Times more Vibrotactile Actuators?’ In: ISMAR 2023 - 22nd IEEE International
Symposium on Mixed and Augmented Reality. Sidney, Australia, 15th Oct. 2023, pp. 1–10. URL:
https://inria.hal.science/hal-04216306.

[39]

[40]

J. Saint-Aubert, F. Argelaguet and A. L. Écuyer. ‘Tangible Avatar : Enhancing Presence and Embodi-
ment During Seated Virtual Experiences with a Prop-Based Controller’. In: ISMAR 2023 - 22nd IEEE
International Symposium on Mixed and Augmented Reality. Sydney, Australia: IEEE, 2023, pp. 1–6.
DOI: 10.1109/ISMAR-Adjunct60411.2023.00121. URL: https://hal.science/hal-043536
16.

J. Saint-Aubert, F. Argelaguet, M. J.-M. Macé, C. Pacchierotti, A. Amedi and A. Lécuyer. ‘Persuasive
Vibrations: Effects of Speech-Based Vibrations on Persuasion, Leadership, and Co-Presence During
Verbal Communication in VR’. In: VR 2023 - IEEE Conference on Virtual Reality and 3D User
Interfaces. Shanghai, China: IEEE, 25th Mar. 2023, pp. 1–9. URL: https://inria.hal.science/h
al-03997713.

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[41] M. F. Vargas, R. Fribourg, E. Bates and R. Mcdonnell. ‘Now I Wanna Be a Dog: Exploring the Impact
of Audio and Tactile Feedback on Animal Embodiment’. In: 2023 IEEE International Symposium on
Mixed and Augmented Reality (ISMAR). ISMAR 2023 - IEEE International Symposium on Mixed
and Augmented Reality. Sydney, Australia: IEEE; IEEE, 2023, pp. 912–921. DOI: 10.1109/ISMAR592
33.2023.00107. URL: https://hal.science/hal-04369761.

Conferences without proceedings

[42] E. Grevet, M. Izac, L. Pillette, F. Amadieu, D. Gasq, J. Py and C. Jeunet-Kelway. ‘Identifying profiles
of patients to personalise BCI-based procedures for motor rehabilitation after stroke’. In: CORTICO
2023 - Annual meeting de COllectif pour la Recherche Transdisciplinaire sur les Interfaces Cerveau-
Ordinateur. Paris, France, 2023, pp. 1–1. URL: https://hal.science/hal-04288958.

[43] E. Grevet, M. Izac, L. Pillette, J. Py, F. Amadieu, D. Gasq and C. Jeunet-Kelway. ‘Acceptability of
BCI-based procedures for motor rehabilitation after stroke: A questionnaire study among patients’.
In: CORTICO 2023 - Journées de COllectif pour la Recherche Transdisciplinaires sur les Interfaces
Cerveau-Ordinateur. Paris, France, 9th May 2023. URL: https://hal.science/hal-04111610.

[44] F. Le Jeune, L. Driessens, E. Savalle and L. Pillette. ‘Which sensations should you imagine?’ In:
COllectif pour la Recherche Transdisciplinaire sur les Interfaces Cerveau-Ordinateur CORTICO
2023. Institut du Cerveau, Paris, France, 8th May 2023. URL: https://hal.science/hal-040871
04.

[45] E. Savalle, L. Pillette, F. Argelaguet Sanz, A. Lécuyer, K.-H. Won and M. J.-M. Macé. ‘Single trial
classification of the level of presence in VR’. In: Cortico 2023 - COllectif pour la Recherche Transdis-
ciplinaire sur les Interfaces Cerveau-Ordinateur. Paris, France, 2023, p. 1. URL: https://hal.scie
nce/hal-04088525.

Scientific book chapters

[46] T. Nicolas, R. Gaugne, B. Arnaldi and V. Gouranton. ‘From medical imaging to virtual reality for
archaeology’. In: L’interdisciplinarité – Voyages au-delà des disciplines. CNRS Editions, 5th Jan. 2023,
p. 316. URL: https://inria.hal.science/hal-03957259.

Edition (books, proceedings, special issue of a journal)

[47] E. Savalle, L. Pillette, F. Argelaguet, A. Lécuyer and M. J.-M. Macé, eds. Measuring presence in a
virtual environment using electroencephalography: A study of breaks in presence using an oddball
paradigm. 10th International BCI Meeting 2023. 9th June 2023. URL: https://hal.science/hal-
04255698.

Other scientific publications

[48] M. Alimardani, V. Gamboa von Groll, N. Leeuwis, S. Rimbert, A. Roc, L. Pillette and F. Lotte. ‘Does
Gender Matter in Motor Imagery BCIs?’ In: BCI Meeting 2023 - 10th International Balancing
Innovation and Translation Meeting. Brussels, Belgium, 6th June 2023. DOI: 10.5281/zenodo.751
6451. URL: https://inria.hal.science/hal-04126907.

[49] P. Dreyer, A. Roc, S. Rimbert, F. Lotte and L. Pillette. ‘DUPE MIBCI: Database with User’s Profile and
EEG signals for Motor Imagery Brain Computer Interface research’. In: BCI 2023 - 10th International
BCI Meeting Balancing Innovation and Translation. Bruxelles, Belgium, 6th June 2023. URL: https:
//hal.science/hal-04125666.

[50] E. Grevet, F. Amadieu, M. Izac, L. Pillette, J. Py, D. Gasq and C. Jeunet-Kelway. ‘Studying the
acceptability of brain-computer interfaces as tools for motor rehabilitation after stroke in order
to design protocols adapted to the profile of each patient’. In: SOFMER 2023 - 38e congrès de la
Société Française de Médecine Physique et de Réadaptation. Le Havre, France, 2023, pp. 1–1. URL:
https://hal.science/hal-04345813.

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12.3 Cited publications

[51] D. A. Bowman, E. Kruijff, J. J. LaViola and I. Poupyrev. 3D User Interfaces: Theory and Practice.

Addison Wesley, 2004.

[52] A. Lécuyer. ‘Simulating Haptic Feedback Using Vision: A Survey of Research and Applications of
Pseudo-Haptic Feedback’. en. In: Presence: Teleoperators and Virtual Environments 18.1 (2009),
pp. 39–53. DOI: 10.1162/pres.18.1.39.
<scratchpad>
- Main topic: Research Centre HYBRID at Inria Rennes
- Key points:
  - Focus on 3D interaction with virtual environments using body and mind
  - Developments in brain-computer interfaces (BCIs) and haptic feedback
  - Applications in industry, medicine, entertainment, education, and cultural heritage
  - Research axes: Body-based interaction, Mind-based interaction, Hybrid and Collaborative interaction
  - Potential applications in rehabilitation, social interactions, and virtual reality
- Structure: The document is organized into sections, including Activity Report, Project-Team HYBRID, Research Program, and Application Domains
- Potential artifacts to ignore: Web-related elements such as links, HTML tags, and images
</scratchpad>

<final_summary>
The HYBRID research centre at Inria Rennes focuses on developing 3D interaction with virtual environments using body and mind. The centre explores various research axes, including body-based interaction, mind-based interaction, and hybrid and collaborative interaction. Developments in brain-computer interfaces (BCIs) and haptic feedback are also a key area of focus. Applications of HYBRID's research include rehabilitation, social interactions, and virtual reality, with potential benefits in industries such as entertainment, education, and cultural heritage. The centre aims to improve user experience and create more immersive and interactive virtual environments.
The HYBRID research centre at Inria Rennes focuses on developing 3D interaction with virtual environments using body and mind. The centre explores various research axes, including body-based interaction, mind-based interaction, and hybrid and collaborative interaction. Developments in brain-computer interfaces (BCIs) and haptic feedback are also a key area of focus. Applications of HYBRID's research include rehabilitation, social interactions, and virtual reality, with potential benefits in industries such as entertainment, education, and cultural heritage. The centre aims to improve user experience and create more immersive and interactive virtual environments.