Non-Traditional Rig for virtual environment systems. Case study: Arm rig

Este trabajo presenta nuevas especificaciones de diseño para rigs de esqueleto basado en problemas encontrados en Entornos Virtuales, tomando en cuenta sus limitaciones y requerimientos, y la relación entre los usuarios y el avatar que encarnan. Este acercamiento es una alternativa al rig de esqueleto tradicionalmente usado en animación, que puede generar deformaciones indeseadas en el mesh, ya que suelen ser hechos con animación artesanal, y optimización de software, en mente. Este Trabajo incluye resultados prometedores en cuanto a una deformación más natural de la muñeca de un personaje digital, validado con la evaluación subjetiva de ocho expertos en el área de producción 3D.1- Introducción 2- Trabajos Previos 3- Nuestro Enfoque 4- Experimento y Resultados 5- ConclusiónThis paper presents new design specifications for skeleton rigs based on Virtual Environment problems, taking into account their limitations and requirements, and the relationship between users and the virtual avatar they embody. This approach is an alternative to traditional skeleton rigs used in animation, which may generate undesirable deformations in the mesh since they are usually made with handcrafted animation, and software optimization, in mind. This work includes promissory results in the naturalness of the deformation of the wrist of a digital character, validated with eight experts’ subjective evaluation in 3D production.Pregrad

Fitted avatars: automatic skeleton adjustment for self-avatars in virtual reality

In the era of the metaverse, self-avatars are gaining popularity, as they can enhance presence and provide embodiment when a user is immersed in Virtual Reality. They are also very important in collaborative Virtual Reality to improve communication through gestures. Whether we are using a complex motion capture solution or a few trackers with inverse kinematics (IK), it is essential to have a good match in size between the avatar and the user, as otherwise mismatches in self-avatar posture could be noticeable for the user. To achieve such a correct match in dimensions, a manual process is often required, with the need for a second person to take measurements of body limbs and introduce them into the system. This process can be time-consuming, and prone to errors. In this paper, we propose an automatic measuring method that simply requires the user to do a small set of exercises while wearing a Head-Mounted Display (HMD), two hand controllers, and three trackers. Our work provides an affordable and quick method to automatically extract user measurements and adjust the virtual humanoid skeleton to the exact dimensions. Our results show that our method can reduce the misalignment produced by the IK system when compared to other solutions that simply apply a uniform scaling to an avatar based on the height of the HMD, and make assumptions about the locations of joints with respect to the trackers.This work was funded by the Spanish Ministry of Science and Innovation (PID2021-122136OB-C21). Jose Luis Ponton was also funded by the Spanish Ministry of Universities (FPU21/01927).Peer ReviewedPostprint (published version

Enhanced visual feedback using Immersive VR affects decision making regarding hand use with a simulated impaired limb

The long-term effects of impairment have a negative impact on the quality of life of stroke patients in terms of not using the affected limb even after some recovery (i.e., learned non-use). Immersive virtual reality (IVR) has been introduced as a new approach for the treatment of stroke rehabilitation. We propose an IVR-based therapeutic approach to incorporate positive reinforcement components in motor coordination as opposed to constraint-induced movement therapy (CIMT). This study aimed to investigate the effect of IVR-reinforced physical therapy that incorporates positive reinforcement components in motor coordination. To simulate affected upper limb function loss in patients, a wrist weight was attached to the dominant hand of participant. Participants were asked to choose their right or left hand to reach toward a randomly allocated target. Themovement of the virtual image of the upper limb was reinforced by visual feedback to participants, that is, the participants perceived their motor coordination as if their upper limb was moving to a greater degree than what was occurring in everyday life. We found that the use of the simulated affected limb was increased after the visual feedback enhancement intervention, and importantly, the effect was maintained even after gradual withdrawal of the visual amplification. The results suggest that positive reinforcement within the IVR could induce an effect on decision making in hand usage

Investigating Trainee Perspectives on Virtual Reality Environments: An In-Depth Examination of Immersive Experiences with Haptic Feedback Vibration

This research investigates trainee reflections on Virithin Reality Environments (VREs) within educational training centers, aiming to understand their experiences, perceptions, and preferences. The study focuses on the impact of haptic feedback vibrations, examining both their general effects during VRE interactions and the specific influence of adaptable vibration configurations triggered by user errors. A convenience sample of 81 participants/trainees, 41 from the computer science and 40 from the aviation engineering departments of a major higher education institution in the U.A.E., was used to run four variations of the same VRE, with two from each field. Results indicate that participants largely embraced the VRE experience, reporting feelings of contentment, joy, and competence. Haptic feedback, particularly in non-adaptable forms, was acknowledged as enhancing the immersive experience. However, the study suggests that further research is needed to explore the nuanced role of adaptable vibration, especially in more complex interactions. Notably, participants expressed a preference for a blended approach, advocating for both VREs and physical labs in their training. The study acknowledges limitations, such as the predominantly single-user focus, and recommends future research extensions into collaborative VRE settings, more intricate interactions, and potential technical issues in multi-user scenarios. Overall, this research sheds light on the evolving landscape of educational training, emphasizing the importance of understanding trainee perspectives to optimize the integration of VREs in learning environment

Virtual Body Ownership Illusions for Mental Health: A Narrative Review.

Over the last 20 years, virtual reality (VR) has been widely used to promote mental health in populations presenting different clinical conditions. Mental health does not refer only to the absence of psychiatric disorders but to the absence of a wide range of clinical conditions that influence people\u2019s general and social well-being such as chronic pain, neurological disorders that lead to motor o perceptual impairments, psychological disorders that alter behaviour and social cognition, or physical conditions like eating disorders or present in amputees. It is known that an accurate perception of oneself and of the surrounding environment are both key elements to enjoy mental health and well-being, and that both can be distorted in patients suffering from the clinical conditions mentioned above. In the past few years, multiple studies have shown the effectiveness of VR to modulate such perceptual distortions of oneself and of the surrounding environment through virtual body ownership illusions. This narrative review aims to review clinical studies that have explored the manipulation of embodied virtual bodies in VR for improving mental health, and to discuss the current state of the art and the challenges for future research in the context of clinical care

The Rocketbox Library and the Utility of Freely Available Rigged Avatars

As part of the open sourcing of the Microsoft Rocketbox avatar library for research and academic purposes, here we discuss the importance of rigged avatars for the Virtual and Augmented Reality (VR, AR) research community. Avatars, virtual representations of humans, are widely used in VR applications. Furthermore many research areas ranging from crowd simulation to neuroscience, psychology, or sociology have used avatars to investigate new theories or to demonstrate how they influence human performance and interactions. We divide this paper in two main parts: the first one gives an overview of the different methods available to create and animate avatars. We cover the current main alternatives for face and body animation as well introduce upcoming capture methods. The second part presents the scientific evidence of the utility of using rigged avatars for embodiment but also for applications such as crowd simulation and entertainment. All in all this paper attempts to convey why rigged avatars will be key to the future of VR and its wide adoption

Modulating the performance of VR navigation tasks using different methods of presenting visual information

Spatial navigation is an essential ability in our daily lives that we use to move through different locations. In Virtual Reality (VR), the environments that users navigate may be large and similar to real world places. It is usually desirable to guide users in order to prevent them from getting lost and to make it easier for them to reach the goal or discover important spots in the environment. However, doing so in a way that the guidance is not intrusive, breaking the immersion and sense of presence, nor too hard to notice, therefore not being useful, can be a challenge. In this work we conducted an experiment in which we adapted a probabilistic learning paradigm: the Weather Prediction task to spatial navigation in VR. Subjects navigated one of the two versions of procedurally generated T-junction mazes in Virtual Reality. In one version, the environment contained visual cues in the form of street signs whose presence predicted the correct turning direction. In the other version the cues were present, but were not predictive. Results showed that when subjects navigated the mazes with the predictive cues they made less mistakes, and therefore the cues helped them navigate the environments. A comparison with previous Neuroscience literature revealed that the strategies used by subjects to solve the task were different than in the original 2D experiment. This work is intended to be used as a basis to further improve spatial navigation in VR with more immersive and implicit methods, and as another example of how the Cognitive Neurosicence and Virtual Reality research fields can greatly benefit each other

Designing User-Centric Private Conversation Methods in the Metaverse

The metaverse is an emerging medium for remote interactions, allowing users to engage in immersive experiences with others in virtual environments, such as attending concerts, business meetings, or social gatherings with friends. Private conversation is an important feature that improves the overall experience in the metaverse. This essential element of virtual interactions allows the exchange of sensitive information and promotes self-disclosure, a key factor in building interpersonal relationships. However, current methods for establishing private conversations have several limitations. In Private Talk, floating icons above the users' avatars do not feel natural and break the immersion. Meanwhile, creating private rooms and teleporting to them disrupts the flow of experience. The goal of this thesis is to design private conversations in the metaverse. First, we surveyed existing methods for establishing private conversations by assessing popular applications and online sources. Second, we developed our own application where we implemented two baseline methods for private conversations, Private Talk and private room. Next, we conducted a user study where we invited 12 participants to evaluate the baseline methods and propose their own methods. We employed questionnaires and conducted interviews to gather suggestions and valuable insights. A thematic analysis of the interview transcripts identified six themes; minimizing background noise, isolation for enhanced feeling of privacy, indicators and distinctions of privacy mode, easy and natural methods in virtual environments, and privacy concerns. From our results, we developed design implications for improving private conversation methods in the metaverse. Our findings aim to guide the design of the future metaverse

Redirected Walk in Place using displacement embodiment

Dentro de la realidad virtual existe un fenómeno denominado motion sickness, una serie de síntomas como nauseas o jaquecas producidas por las discrepancias entre lo que vemos en los dispositivos y lo que hacemos en el mundo físico. Uno de los métodos que consigue reducir el problema es la metodología Walk-in-place, donde el usuario camina sobre un sitio fijo de forma que solo alza o baja los pies y, en base a este movimiento, se produce un desplazamiento en el entorno virtual. Al obtener una relación directa entre el desplazamiento y las acciones del usuario, los efectos negativos se ven reducidos. Esta solución al problema, sin embargo, cuenta con que el usuario se mueva sobre un mismo sitio, algo que, al carecer de una referencia del mundo real mientras se usan los dispositivos VR, acaba por suponer un desplazamiento físico del jugador dentro de la zona segura de juego pudiendo llegar a salirse de esta provocando accidentes (chocar con muebles, contra una pared, etc.). Teniendo en cuenta todo lo anterior, el objetivo de este proyecto es aprovechar el avatar (modelo 3D de las personas) del entorno y la reacción automática del usuario al darse cuenta de la discrepancia entre él y el modelo para incitar la vuelta de este al centro de su zona segura. De esta forma se hallaría una solución no intrusiva al desplazamiento inconsciente en el mundo físico que acabaría con los accidentes. Para llevar a cabo esta tarea, se ha diseñado un modelo con el que el usuario puede identificarse, que siempre está situado en el centro de la zona segura, de modo que cuando se produzca la desviación de la posición del usuario, este sea capaz de ver su modelo desplazado y pueda corregir su posición. Este proyecto pretende llevar a cabo un sistema que implemente esta idea ya sea de forma parcial o total y permita más adelante el análisis de los datos necesarios para extraer conclusiones.Virtual Reality has a group of side effects related to it named motion sickness. These symptoms include dizziness, headaches and other ones due to some inconsistencies of the visual and Physical stimulus while being in a simulation. One of the methods used to reduce these symptoms is called Walk-in-place, which directly converts the static walking into real movement inside the simulation, therefore inconsistencies are decreased and with that, the sickness. This method however, has another problem that comes with it, and it involves a subtle movement that causes the player to walk away from the centre or the safe zone causing in the end accidents or unintended collisions with walls or furniture. This problem endangers user's safety because of the limitations in the real world. Keeping this in mind, this project intends to use the avatar of the simulation to hint the user to relocate himself to the safe zone. In order to achieve this, the model is always located in the centre of the playing zone so that the user can identify the discrepancy between himself and the avatar while playing, therefore, allowing him to correct his position. The project pretends to solve this problem totally or partially implementing the idea and later making an experiment to analyse the results