2020 IEEE Conference on Virtual Reality and 3D User Interfaces Abstracts and Workshops (VRW)
Cybersickness continues to be one of the main barriers for mainstream adoption of Virtual Reality... more Cybersickness continues to be one of the main barriers for mainstream adoption of Virtual Reality (VR). Despite the wealth of research available on this topic, it is still an unsolved problem. This paper explores the potential influence of cybersickness over the course of a VR experience on player Blink-Rate. This investigation was conducted on the same VR task with two diverging control schemes with a low or high risk of inducing cybersickness. A total of 34 participant data was collected from two separate playing sessions. Although no significant differences were observed, sick individuals showed to have a higher blink-rate frequency over the course of the VR experience while non-sick individuals presented a more stable blink-rate frequency.
Virtual Reality (VR) has the capability of fully immersing users into a wide variety of gaming ex... more Virtual Reality (VR) has the capability of fully immersing users into a wide variety of gaming experiences where the sole focus of the user is on that experience itself. One problem that often occurs when it comes to VR experiences is that of simulation sickness (SS), which is particularly prevalent when the user is forced to play at an abnormal posture due to physical limitations or specific treatment procedures. In this paper we report on a between group study comparing the effect of SS mitigating factors for two postures: seated and lying-down on one’s back (known as the supine pose). A 3D recreation of the popular game Pacman (Namco, 1980) was developed specifically for VR. Each subject participated a total of six sessions of six minutes each taking place over the course of two to three weeks with a two to five day minimum and maximum between each session, respectively. At the start and end of each session participants were asked to fill-in the Simulator Sickness Questionnaire (...
IEEE transactions on visualization and computer graphics, 2018
With the broad range of motion capture devices available on the market, it is now commonplace to ... more With the broad range of motion capture devices available on the market, it is now commonplace to directly control the limb movement of an avatar during immersion in a virtual environment. Here, we study how the subjective experience of embodying a full-body controlled avatar is influenced by motor alteration and self-contact mismatches. Self-contact is in particular a strong source of passive haptic feedback and we assume it to bring a clear benefit in terms of embodiment. For evaluating this hypothesis, we experimentally manipulate self-contacts and the virtual hand displacement relatively to the body. We introduce these body posture transformations to experimentally reproduce the imperfect or incorrect mapping between real and virtual bodies, with the goal of quantifying the limits of acceptance for distorted mapping on the reported body ownership and agency. We first describe how we exploit egocentric coordinate representations to perform a motion capture ensuring that real and v...
In this paper, we propose a hybrid postural control approach taking advantage of data-driven and ... more In this paper, we propose a hybrid postural control approach taking advantage of data-driven and goal-oriented methods while overcoming their limitations. In particular, we take advantage of the latent space characterizing a given motion database. We introduce a motion constraint operating in the latent space to benefit from its much smaller dimension compared to the joint space. This allows its transparent integration into a Prioritized Inverse Kinematics framework. If its priority is high the constraint may restrict the solution to lie within the motion database space. We are more interested in the alternate case of an intermediate priority level that channels the postural control through a spatiotemporal pattern representative of the motion database while achieving a broader range of goals. We illustrate this concept with a sparse database of large range full-body reach motion
We focus on retargetting the class of movements involving self-interactions onto characters with ... more We focus on retargetting the class of movements involving self-interactions onto characters with different size and proportion. Such postures may produce self-collisions and/or alter the intended semantics. We introduce a technique to normalize the spatial relationship vectors between the body parts of the source character. This allows for morphological adaptation of these vectors onto the target characters, hence preserving the semantics in postures with and without body-contact.
Cybersickness induced through Virtual Reality (VR) applications is still one of its main barriers... more Cybersickness induced through Virtual Reality (VR) applications is still one of its main barriers as it can induce unwanted sideeffects in players, significantly hindering the overall experience. Despite the wealth of research available on this topic, it is still an unsolved problem. Although previous studies have explored methods of cybersickness mitigation in addition to correlating physiological factors, there has been little research on the potential correlation of eye behavior and cybersickness. Thanks to advances in eye-tracking technology within HMDs, detecting eye behavior has become a much easier process. This paper explores the differences of pupil position and blink rate in relation to cybersickness intensity. The latter is measured through the standard and a customized version of the Simulator Sickness Questionnaire (SSQ). A total of 34 participant data was collected from two separate playing sessions of a VR maze game, where each session presented a unique control scheme.
IEEE Transactions on Visualization and Computer Graphics, 2021
In Virtual Reality, having a virtual body opens a wide range of possibilities as the participant'... more In Virtual Reality, having a virtual body opens a wide range of possibilities as the participant's avatar can appear to be quite different from oneself for the sake of the targeted application (e.g., for perspective-taking). In addition, the system can partially manipulate the displayed avatar movement through some distortion to make the overall experience more enjoyable and effective (e.g., training, exercising, rehabilitation). Despite its potential, an excessive distortion may become noticeable and break the feeling of being embodied into the avatar. Past researches have shown that individuals have a relatively high tolerance to movement distortions and a great variability of individual sensitivities to distortions. In this article, we propose a method taking advantage of Reinforcement Learning (RL) to efficiently identify the magnitude of the maximum distortion that does not get noticed by an individual (further noted the detection threshold). We show through a controlled experiment with subjects that the RL method finds a more robust detection threshold compared to the adaptive staircase method, i.e., it is more able to prevent subjects from detecting the distortion when its amplitude is equal or below the threshold. Finally, the associated majority voting system makes the RL method able to handle more noise within the forced choices input than adaptive staircase. This last feature is essential for future use with physiological signals as these latter are even more susceptible to noise. It would then allow to calibrate embodiment individually to increase the effectiveness of the proposed interactions.
2018 IEEE Conference on Virtual Reality and 3D User Interfaces (VR), 2018
We investigate the self-attribution of distorted pointing movements in immersive virtual reality.... more We investigate the self-attribution of distorted pointing movements in immersive virtual reality. Participants had to complete a multidirectional pointing task in which the visual feedback of the tapping finger could be deviated in order to increase or decrease the motor size of a target relative to its visual appearance. This manipulation effectively makes the task easier or harder than the visual feedback suggests. Participants were asked whether the seen movement was equivalent to the movement they performed, and whether they have been successful in the task. We show that participants are often unaware of the movement manipulation, even when it requires higher pointing precision than suggested by the visual feedback. Moreover, subjects tend to self-attribute movements that have been modified to make the task easier more often than movements that have not been distorted. We discuss the implications and applications of our results.
IEEE Transactions on Computational Intelligence and AI in Games, 2017
Creating interactive characters is one of the most challenging tasks of videogame design. In orde... more Creating interactive characters is one of the most challenging tasks of videogame design. In order to facilitate such an endeavour, we introduce a decisional and behaviour synthesis architecture integrated in the game engine Unity3D. A distinguishing feature of this architecture is that it embraces embodied cognition principles and uses them as implementation requirements. From these we derive an architecture which is based on a novel combination of previously proposed systems, together with some simplifications. We also argue that the architecture proposed has propertiesmodularity, scalability, stability-which can be beneficial for its practical industrial adoption, particularly in the context of the recent improvement in machine learning techniques. Artificial intelligence is a quite technical domain, and we believe such a tool can facilitate interactive character creation by creative minds in industrial applications.
This paper presents an interactive tool dedicated to the design of walking trajectories for human... more This paper presents an interactive tool dedicated to the design of walking trajectories for human figures. It uses a global human free-walking model built from experimental data on a wide range of normalized velocities. This tool is particularly efficient in that the higher level of the ...
Abstract Proposes a general framework to enhance grasping interactions of an operator wearing a d... more Abstract Proposes a general framework to enhance grasping interactions of an operator wearing a digital glove. The authors focus on a consistent interpretation of the posture information acquired with the glove in order to reflect the grasp of virtual artifacts. This ...
We describe the HUMANOID environment dedicated to human modeling and animation for generalmultime... more We describe the HUMANOID environment dedicated to human modeling and animation for generalmultimedia, VR, and CAD applications integrating virtual humans. We present the design of the system andthe integration of the various features: generic modeling of a large class of entities with the BODY datastructure, realistic skin deformation for body and hands, facial animation, collision detection, integratedmotion control and parallelization of computation intensive tasks.
We propose an Inverse Kinematic Control architecture capable of handling tasks that are expressed... more We propose an Inverse Kinematic Control architecture capable of handling tasks that are expressed in terms of inequality constraints in the Cartesian space. These inequality constraints are progressive in the sense that their influence manifests itself in a zone of finite thickness by damping the progression toward the strict limit of the constraint. We show how to enforce this family of constraints in a two stage process with our prioritized IK sheme. Various examples highlight the potential of this approach for managing complex articulated chains in cluttered environments where obstacles are modelled with this type of constraints.
2020 IEEE Conference on Virtual Reality and 3D User Interfaces Abstracts and Workshops (VRW)
Cybersickness continues to be one of the main barriers for mainstream adoption of Virtual Reality... more Cybersickness continues to be one of the main barriers for mainstream adoption of Virtual Reality (VR). Despite the wealth of research available on this topic, it is still an unsolved problem. This paper explores the potential influence of cybersickness over the course of a VR experience on player Blink-Rate. This investigation was conducted on the same VR task with two diverging control schemes with a low or high risk of inducing cybersickness. A total of 34 participant data was collected from two separate playing sessions. Although no significant differences were observed, sick individuals showed to have a higher blink-rate frequency over the course of the VR experience while non-sick individuals presented a more stable blink-rate frequency.
Virtual Reality (VR) has the capability of fully immersing users into a wide variety of gaming ex... more Virtual Reality (VR) has the capability of fully immersing users into a wide variety of gaming experiences where the sole focus of the user is on that experience itself. One problem that often occurs when it comes to VR experiences is that of simulation sickness (SS), which is particularly prevalent when the user is forced to play at an abnormal posture due to physical limitations or specific treatment procedures. In this paper we report on a between group study comparing the effect of SS mitigating factors for two postures: seated and lying-down on one’s back (known as the supine pose). A 3D recreation of the popular game Pacman (Namco, 1980) was developed specifically for VR. Each subject participated a total of six sessions of six minutes each taking place over the course of two to three weeks with a two to five day minimum and maximum between each session, respectively. At the start and end of each session participants were asked to fill-in the Simulator Sickness Questionnaire (...
IEEE transactions on visualization and computer graphics, 2018
With the broad range of motion capture devices available on the market, it is now commonplace to ... more With the broad range of motion capture devices available on the market, it is now commonplace to directly control the limb movement of an avatar during immersion in a virtual environment. Here, we study how the subjective experience of embodying a full-body controlled avatar is influenced by motor alteration and self-contact mismatches. Self-contact is in particular a strong source of passive haptic feedback and we assume it to bring a clear benefit in terms of embodiment. For evaluating this hypothesis, we experimentally manipulate self-contacts and the virtual hand displacement relatively to the body. We introduce these body posture transformations to experimentally reproduce the imperfect or incorrect mapping between real and virtual bodies, with the goal of quantifying the limits of acceptance for distorted mapping on the reported body ownership and agency. We first describe how we exploit egocentric coordinate representations to perform a motion capture ensuring that real and v...
In this paper, we propose a hybrid postural control approach taking advantage of data-driven and ... more In this paper, we propose a hybrid postural control approach taking advantage of data-driven and goal-oriented methods while overcoming their limitations. In particular, we take advantage of the latent space characterizing a given motion database. We introduce a motion constraint operating in the latent space to benefit from its much smaller dimension compared to the joint space. This allows its transparent integration into a Prioritized Inverse Kinematics framework. If its priority is high the constraint may restrict the solution to lie within the motion database space. We are more interested in the alternate case of an intermediate priority level that channels the postural control through a spatiotemporal pattern representative of the motion database while achieving a broader range of goals. We illustrate this concept with a sparse database of large range full-body reach motion
We focus on retargetting the class of movements involving self-interactions onto characters with ... more We focus on retargetting the class of movements involving self-interactions onto characters with different size and proportion. Such postures may produce self-collisions and/or alter the intended semantics. We introduce a technique to normalize the spatial relationship vectors between the body parts of the source character. This allows for morphological adaptation of these vectors onto the target characters, hence preserving the semantics in postures with and without body-contact.
Cybersickness induced through Virtual Reality (VR) applications is still one of its main barriers... more Cybersickness induced through Virtual Reality (VR) applications is still one of its main barriers as it can induce unwanted sideeffects in players, significantly hindering the overall experience. Despite the wealth of research available on this topic, it is still an unsolved problem. Although previous studies have explored methods of cybersickness mitigation in addition to correlating physiological factors, there has been little research on the potential correlation of eye behavior and cybersickness. Thanks to advances in eye-tracking technology within HMDs, detecting eye behavior has become a much easier process. This paper explores the differences of pupil position and blink rate in relation to cybersickness intensity. The latter is measured through the standard and a customized version of the Simulator Sickness Questionnaire (SSQ). A total of 34 participant data was collected from two separate playing sessions of a VR maze game, where each session presented a unique control scheme.
IEEE Transactions on Visualization and Computer Graphics, 2021
In Virtual Reality, having a virtual body opens a wide range of possibilities as the participant'... more In Virtual Reality, having a virtual body opens a wide range of possibilities as the participant's avatar can appear to be quite different from oneself for the sake of the targeted application (e.g., for perspective-taking). In addition, the system can partially manipulate the displayed avatar movement through some distortion to make the overall experience more enjoyable and effective (e.g., training, exercising, rehabilitation). Despite its potential, an excessive distortion may become noticeable and break the feeling of being embodied into the avatar. Past researches have shown that individuals have a relatively high tolerance to movement distortions and a great variability of individual sensitivities to distortions. In this article, we propose a method taking advantage of Reinforcement Learning (RL) to efficiently identify the magnitude of the maximum distortion that does not get noticed by an individual (further noted the detection threshold). We show through a controlled experiment with subjects that the RL method finds a more robust detection threshold compared to the adaptive staircase method, i.e., it is more able to prevent subjects from detecting the distortion when its amplitude is equal or below the threshold. Finally, the associated majority voting system makes the RL method able to handle more noise within the forced choices input than adaptive staircase. This last feature is essential for future use with physiological signals as these latter are even more susceptible to noise. It would then allow to calibrate embodiment individually to increase the effectiveness of the proposed interactions.
2018 IEEE Conference on Virtual Reality and 3D User Interfaces (VR), 2018
We investigate the self-attribution of distorted pointing movements in immersive virtual reality.... more We investigate the self-attribution of distorted pointing movements in immersive virtual reality. Participants had to complete a multidirectional pointing task in which the visual feedback of the tapping finger could be deviated in order to increase or decrease the motor size of a target relative to its visual appearance. This manipulation effectively makes the task easier or harder than the visual feedback suggests. Participants were asked whether the seen movement was equivalent to the movement they performed, and whether they have been successful in the task. We show that participants are often unaware of the movement manipulation, even when it requires higher pointing precision than suggested by the visual feedback. Moreover, subjects tend to self-attribute movements that have been modified to make the task easier more often than movements that have not been distorted. We discuss the implications and applications of our results.
IEEE Transactions on Computational Intelligence and AI in Games, 2017
Creating interactive characters is one of the most challenging tasks of videogame design. In orde... more Creating interactive characters is one of the most challenging tasks of videogame design. In order to facilitate such an endeavour, we introduce a decisional and behaviour synthesis architecture integrated in the game engine Unity3D. A distinguishing feature of this architecture is that it embraces embodied cognition principles and uses them as implementation requirements. From these we derive an architecture which is based on a novel combination of previously proposed systems, together with some simplifications. We also argue that the architecture proposed has propertiesmodularity, scalability, stability-which can be beneficial for its practical industrial adoption, particularly in the context of the recent improvement in machine learning techniques. Artificial intelligence is a quite technical domain, and we believe such a tool can facilitate interactive character creation by creative minds in industrial applications.
This paper presents an interactive tool dedicated to the design of walking trajectories for human... more This paper presents an interactive tool dedicated to the design of walking trajectories for human figures. It uses a global human free-walking model built from experimental data on a wide range of normalized velocities. This tool is particularly efficient in that the higher level of the ...
Abstract Proposes a general framework to enhance grasping interactions of an operator wearing a d... more Abstract Proposes a general framework to enhance grasping interactions of an operator wearing a digital glove. The authors focus on a consistent interpretation of the posture information acquired with the glove in order to reflect the grasp of virtual artifacts. This ...
We describe the HUMANOID environment dedicated to human modeling and animation for generalmultime... more We describe the HUMANOID environment dedicated to human modeling and animation for generalmultimedia, VR, and CAD applications integrating virtual humans. We present the design of the system andthe integration of the various features: generic modeling of a large class of entities with the BODY datastructure, realistic skin deformation for body and hands, facial animation, collision detection, integratedmotion control and parallelization of computation intensive tasks.
We propose an Inverse Kinematic Control architecture capable of handling tasks that are expressed... more We propose an Inverse Kinematic Control architecture capable of handling tasks that are expressed in terms of inequality constraints in the Cartesian space. These inequality constraints are progressive in the sense that their influence manifests itself in a zone of finite thickness by damping the progression toward the strict limit of the constraint. We show how to enforce this family of constraints in a two stage process with our prioritized IK sheme. Various examples highlight the potential of this approach for managing complex articulated chains in cluttered environments where obstacles are modelled with this type of constraints.
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Papers by Ronan Boulic