Virtual reality is becoming increasingly popular, and modern haptic equipment, such as vibrotactile suits, haptic gloves, and force-feedback controllers, offers new means of interaction within virtual environments, significantly enhancing user experience. When interacting with virtual objects, combined visual and haptic feedback simulates the physical sensations of grasping, lifting, or moving real objects. This sensorimotor feedback is essential for inducing a sense of presence and agency, yet it remains challenging to reproduce in the absence of reliable haptic cues. In this study, we design and evaluate several haptic metaphors using combinations of vibrotactile design parameters to simulate the lifting effort associated with light to heavy objects. These parameters include primitive signals, intensity, spatial density, propagation, and temporal density. Our contribution is threefold. First, we propose a method for modulating perceived physical effort by extending signal intensity with spatial and temporal density, which together reflect the effort required to lift an object. Second, we present a user study in which participants compared haptic effects and ranked them according to perceived lifting effort, comfort, and confidence, allowing us to assess the influence of each parameter. Third, we report the results of a second study in which participants evaluated vibrotactile effects when lifting different virtual objects. The findings confirm the importance of intensity and spatial density, as well as the influence of graphical representation on perceived effort. This research provides practical insights for designing haptic-enabled virtual reality systems and offers guidance for developers seeking to create more expressive and believable vibrotactile interactions.

The utilization of virtual reality (VR) technology has shown promise in various therapeutic applications, particularly in exposure therapy for reducing fear of certain situations objects or activities, e.g. fear of height, or negative evaluation of others in social situations. VR has been shown to yield positive outcomes in follow-up studies, and provides a safe and ecological therapeutic environment for therapists and their patients. This paper presents a collaborative effort to develop a VR speech therapy system which simulates a virtual audience for users to practice their public speaking skills. We describe a novel web-based graphical user interface that enables therapists to manage the therapy session using a simple timeline. Lastly, we present the results from a qualitative study with therapists and teachers with functional dysphonia, which highlight the potential of such an application to support and augment the therapists' work and the remaining challenges regarding the design of natural interactions, agent behaviours and scenario customisation for patients.

This paper presents the development and preliminary evaluation of a personality enhancer behaviour model for virtual audiences to increase their realism and individualism. We conducted a systematic literature review and identified sixteen posture parameters to modify seated animations dynamically, calling them personality enhancers. We grouped them into four main categories: body, gaze, face and gesture behaviour modifiers. We implemented a unique animation modifier system on top of a game engine to apply these personality enhancers on existing pre-recorded generic seated animations. The first results with sixty participants in an online video survey show that the model can successfully simulate individuals with low and high levels of extroversion as well as with low and high levels of emotional stability.

This paper presents the first prototype of a virtual audience system (VAS) specifically designed as a training tool for conference talks. This system has been tailored for university seminars dedicated to the preparation and delivery of scientific talks. We describe the required features which have been identified during the development process. We also summarize the preliminary feedback received from lecturers and students during the first deployment of the system in seminars for bachelor and doctoral students. Finally, we discuss future work and research directions. We believe our system architecture and features are providing interesting insights on the development and integration of VR-based educational tools into university curriculum.

In this paper, we describe the implementation and performance of a Virtual Audience perception model for Virtual Reality (VR). The model is a VR adaptation of an existing desktop model. The system allows a user in VR to easily build and experience a wide variety of atmospheres with small or large groups of virtual agents.The paper describes results of early evaluations for this model in VR. Our first scalability benchmark results demonstrated the ability to simultaneously handle one hundred virtual agents without significantly affecting there commended frame rate for VR applications.This research is conducted in the context of a classroom simulation software for teachers’ training.