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.
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.
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.
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