Navigating topographic charts involves nuanced skills and real-world correspondence, influenced by individual learning styles. Traditionally, 2D and 3D representations bridge map-reality gaps, but sandboxes often introduce manual errors and reliance on personal interpretation. This paper examines VR's potential in military planning, focusing on terrain interpretation, data visualization, and scale transitions. A study with 36 army cadets investigates VR's effectiveness in enhancing spatial perception and real-world task performance. Findings suggest that VR improves position choices and grades and reduces result disparities, particularly benefiting users with lower spatial skills. The research also evaluates the impact of different scales on VR planning, offering insights into potential advantages and challenges. Future studies should explore control issues and completion times in real-world scenarios.

course Share on Approaches and Challenges in XR and AI for Health Applications Authors: Joaquim Jorge INESC-ID & IST, Universidade de Lisboa INESC-ID & IST, Universidade de LisboaView Profile , João Pereira INESC-ID & IST, Universidade de Lisboa INESC-ID & IST, Universidade de LisboaView Profile , Anderson Maciel INESC-ID & IST, Universidade de Lisboa INESC-ID & IST, Universidade de LisboaView Profile , Catarina Moreira Technical University Sydney Technical University SydneyView Profile , Regis Kopper UNC Greensboro UNC GreensboroView Profile Authors Info & Claims SA '23: SIGGRAPH Asia 2023 CoursesDecember 2023Article No.: 2Pages 1–147https://doi.org/10.1145/3610538.3614640Published:06 December 2023Publication History 0citation52DownloadsMetricsTotal Citations0Total Downloads52Last 12 Months52Last 6 weeks15 Get Citation AlertsNew Citation Alert added!This alert has been successfully added and will be sent to:You will be notified whenever a record that you have chosen has been cited.To manage your alert preferences, click on the button below.Manage my AlertsNew Citation Alert!Please log in to your account Save to BinderSave to BinderCreate a New BinderNameCancelCreateExport CitationPublisher SiteGet Access

Whenever accessing indoor spaces such as classrooms or auditoriums, people might attempt to analyze and choose an appropriate place to stay while attending an event. Several criteria may be accounted for, and most are not always self-evident or trivial. This work proposes the use of data visualization allied to an Augmented Reality (AR) user interface to help users defining the most convenient seats to take. We consider sets of arbitrary demands and project information directly atop the seats and all around the room. Users can also narrow down the search by switching and combining the attributes being displayed, e.g., temperature, wheelchair accessibility. The proposed approach was tested against a comparable 2D interactive visualization of the same data in usability assessments of seat-choosing tasks with a set of users (N = 16) to validate the solution. Qualitative and quantitative data indicated that the AR-based solution is promising, suggesting that AR may help users make more accurate decisions, even in an ordinary daily task. Regarding Augmented Situated Visualization, our results open new avenues for the exploration of context-aware data.

We present an assessment of asymmetric interactions in Collaborative Virtual Environments (CVEs). In our asymmetric setup, two co-located users interact with virtual 3D objects, one in immersive Virtual Reality (VR) and the other in mobile Augmented Reality (AR). We conducted a study with 36 participants to evaluate performance and collaboration aspects of pair work, and compare it with two symmetric scenarios, either with both users in immersive VR or mobile AR. To perform this experiment, we adopt a collaborative AR manipulation technique from literature and develop and evaluate a VR manipulation technique of our own. Our results indicate that pairs in asymmetric VR-AR achieved significantly better performance than the AR symmetric condition, and similar performance to VR symmetric. Regardless of the condition, pairs had similar work participation indicating a high cooperation level even when there is a visualization and interaction asymmetry between the participants.

Abstract The visual fidelity of realistic renderings in Computer Graphics depends fundamentally upon how we model the appearance of objects resulting from the interaction between light and matter reaching the eye. In this paper, we survey the research addressing appearance modelling of living human tissue. Among the many classes of natural materials already researched in Computer Graphics, living human tissues such as blood and skin have recently seen an increase in attention from graphics research. There is already an incipient but substantial body of literature on this topic, but we also lack a structured review as presented here. We introduce a classification for the approaches using the four types of human tissues as classifiers. We show a growing trend of solutions that use first principles from Physics and Biology as fundamental knowledge upon which the models are built. The organic quality of visual results provided by these Biophysical approaches is mainly determined by the optical properties of biophysical components interacting with light. Beyond just picture making, these models can be used in predictive simulations, with the potential for impact in many other areas.

We present the design of a handheld-based interface for collaborative manipulations of 3D objects in mobile augmented reality. Our approach combines touch gestures and device movements for fast and precise control of 7-DOF transformations. Moreover, the interface creates a shared medium where several users can interact through their point-of-view and simultaneously manipulate 3D virtual augmentations. We evaluated our collaborative solution in two parts. First, we assessed our interface in single user mode, comparing the user task performance in three conditions: touch gestures, device movements and hybrid. Then, we conducted a study with 30 participants to understand and classify the strategies that arise while working in pairs, when partners are free to make their task organization. Furthermore, we investigated the effectiveness of simultaneous manipulations compared with the individual approach.

In the context of the 3DUI Contest promoted by the IEEE VR 2018, we propose 3D interaction techniques that address three distinct tasks in a virtual environment setup: climbing a ladder, controlling a quadcopter in a first-person view flight, and building a tower by stacking a series of objects. The interaction techniques were developed so the player, our 3D-athlete, has control over the events in each task, following metaphors that facilitate the use of the interface, and having status and spatial awareness supported by clear feedback cues. Thus, the player should be able to execute the tasks with precision and agility.

Object manipulation in 3D virtual environments demands a combined coordination of rotations, translations and scales, as well as the camera control to change the user's viewpoint. Then, for many manipulation tasks, it would be advantageous to share the interaction complexity among team members. In this paper we propose a novel 3D manipulation interface based on a collaborative action coordination approach. Our technique explores a smartphone -- the touchscreen and inertial sensors -- as input interface, enabling several users to collaboratively manipulate the same virtual object with their own devices. We first assessed our interface design on a docking and an obstacle crossing tasks with teams of two users. Then, we conducted a study with 60 users to understand the influence of group size in collaborative 3D manipulation. We evaluated teams in combinations of one, two, three and four participants. Experimental results show that teamwork increases accuracy when compared with a single user. The accuracy increase is correlated with the number of individuals in the team and their work division strategy.

Vibrotactile feedback is broadly used to support different tasks in virtual and augmented reality applications, such as navigation, communication, attentional redirection, or to enhance the sense of presence in virtual environments. Thus, we aim to include the haptic component to the most popular wearable used in VR applications: the VR headset. After studying the acuity around the head for vibrating stimuli, and trying different parameters, actuators, and configurations, we developed a haptic guidance technique to be used in a vibrotactile Head-mounted Display (HMD). Our vi-brotactile HMD was made to render the position of objects in a 3D space around the subject by varying both stimulus loci and vibration frequency. In this demonstration, the participants will interact with different scenarios where the mission is to select a number of predefined objects. However, instead of displaying occlusive graphical information to point to these objects, vibrotactile cues will provide guidance in the VR setup. Participants will see that our haptic guidance technique can be both easy to use and entertaining. (See Video: https://youtu.be/_H0MQy6QD7M).

Due to the perceptual characteristics of the head, vibrotactile Head-mounted Displays are built with low actuator density. Therefore, vibrotactile guidance is mostly assessed by pointing towards objects in the azimuthal plane. When it comes to multisensory interaction in 3D environments, it is also important to convey information about objects in the elevation plane. In this paper, we design and assess a haptic guidance technique for 3D environments. First, we explore the modulation of vibration frequency to indicate the position of objects in the elevation plane. Then, we assessed a vibrotactile HMD made to render the position of objects in a 3D space around the subject by varying both stimulus loci and vibration frequency. Results have shown that frequencies modulated with a quadratic growth function allowed a more accurate, precise, and faster target localization in an active head pointing task. The technique presented high usability and a strong learning effect for a haptic search across different scenarios in an immersive VR setup.

Communication is crucial in collaborative tasks. Multimodal strategies are commonly applied to complement, reinforce and disam-biguate information exchange. However, although multimodal communication is commonplace in Collaborative Virtual Environments, the proactive use of touch for intercommunication is surprisingly neglected regardless its importance for communication. In this paper, we look up to elements present in speech articulation to introduce the proactive haptic articulation as a novel approach for communication in CVEs. We defend the hypothesis that elements present in natural language, when added to the design of the vibro-tactile vocabulary, should provide an expressive medium for intercommunication. Moreover, we hypothesize that the ability to render tactile cues to a teammate will encourage users to adapt a given vocabulary spontaneously during its use. We implemented a case study around a collaborative puzzle task to demonstrate the use of such vocabulary. Results show that the proactive haptic articulation provided a way for participants to autonomously and dynamically adapt the provided tactile vocabulary to attend their communication needs during the task.

In the radiology diagnosis process, medical images are most often visualized slice by slice on 2D screens or printed. At the same time, the visualization based on 3D volumetric rendering of the data is considered useful and has increased its field of application. In this work we present a user study with medical specialists to assess the diagnostic effectiveness of VR usage in fracture identification over 3D volumetric reconstructions. We then performed user experiments to validate the approach in the medical practice. In addition, we assessed the subjects perception of the 3D reconstruction quality and ease of interaction. Among other results, we have found a very high level of effectiveness of the VR interface in identifying superficial fractures on head CTs.

Communication is a fundamental process in collaborative work. In natural conditions, communication between team members is multimodal. This allows for redundancy, adaptation to different contexts, and different levels of focus. In collaborative virtual environments, however, hardware limitations and lack of appropriate interaction metaphors reduce the amount of collaboration. In this poster, we propose the design and use of a vibrotactile language to improve user intercommunication in CVE and, consequently, to increase the amount of effective collaboration.

Most human computer interfaces impose a certain level of additional cognitive load to the user task. In this project we study the use of VR to evaluate the user competency for safe behavior in work environments. We propose an assessment of two interfaces with different levels of cognitive load for locomotion in a risk perception task. We describe user experiments with two similar groups of subjects, each using one of the interfaces. We identified important open questions on the design of this kind of interface.

In this demo we present an immersive virtual reality (VR) simulator to measure risk perception in realistic working environments. It provides the ideal environment to expose people to danger with no chances to cause them any harm. However, whereas in the physical work environment workers have to perform their jobs (primary task) and be safe (secondary task), in a VR simulator they still have to deal with an additional source of cognitive load: the user interface.

We present Disambiguation canvas, a technique for selection by progressive refinement using a mobile device and consisting of two steps. During the first, the user defines a subset of objects through the orientation sensors of the device and a volume-casting pointing technique. The subsequent step consists of the disambiguation of the desired target among the previously-defined subset of objects, and is accomplished using the mobile device touchscreen. By relying on the touchscreen for the last step the user can disambiguate among hundreds of objects at once, previous progressive refinement techniques do not scale as well as ours. Disambiguation canvas is mainly developed for easy, accurate and fast selection of small objects, or objects inside cluttered virtual environments. User tests show that our technique performs faster than ray-casting for targets with ≈ 0.53° of angular size, and is also much more accurate for all the tested target sizes.

Collaboration in 3D environments has the main goal of attaining a high degree of teamwork by exposing the team to a suitable level of immersion. However, users within virtual environments have limitations to perceive the same stimuli of the real world. Particularly, the feeling of presence and nearness of the other is difficult to be generated in VR systems. This poster presents a work in progress that shows our current results on evaluating the impact of three different proximity cues for generating awareness of the presence of other. The design of each cue aims at independently stimulating the senses of sight, hearing and touch. The experiment design includes the comparison with a baseline condition in virtual environments where no specific stimulation is applied.

Any human-computer interface imposes a certain level of cognitive load to the user task. Analogously, the task itself also imposes different levels of cognitive load. It is common sense in 3D user interfaces research that a higher number of degrees of freedom increases the interface cognitive load. If the cognitive load is significant, it might compromise the user performance and undermine the evaluation of user skills in a virtual environment. In this paper, we propose an assessment of two immersive VR interfaces with varying degrees of freedom in two VR tasks: risk perception and basic object selection. We examine the effectiveness of both interfaces in these two different tasks. Results show that the number of degrees of freedom does not significantly affect a basic selection task, but it affects risk perception task in an unexpected way.

Deformation of objects geometry in computer graphics has been based on a number of different approaches. Two classes of methods are highlighted: physics-based and geometry-based. Physics-based methods, such as Mass-Spring Damper, Finite Element Method and Point-Associated Finite Field have been applied to model soft tissue. However, they all have difficulties in handling the compromise between physical realism and performance. Such difficulties can comprehend the complexity in setting physical parameters of the object, large computational cost and high complexity in implementation. This work proposes a case study evaluation on the Mass-Spring Damper model. A set of well known physical engines are analyzed, allowing to understand how the implementation decisions influence performance and accuracy. These results are compared with an implementation especially proposed for this study.

In real time computer graphics, "interactivity" is limited to a display rate of 30 frames per second. However, in multimodal virtual environments involving haptic interactions, a much higher update rate of about 1 kHz is necessary to ensure continuous interactions and smooth transitions. The simplest and most efficient interaction paradigm in such environments is to represent the haptic cursor as a point. However, in many situations, such as those in the development of real time medical simulations involving the interactions of long slender surgical tools with soft deformable organs, such a paradigm is nonrealistic and at least a line-based interaction is desirable. While such paradigms exist, the main impediment to their widespread use is the associated computational complexity. In this paper, we introduce, for the first time, an efficient algorithm for computing the interaction of a line-shaped haptic cursor and polygonal surface models which has a near constant complexity. The algorithm relies on space-time coherence, topological information, and the properties of lines in 3D space to maintain proximity information between a line segment and triangle meshes. For interaction with convex objects, the line is represented by its end points and a dynamic point, which is the closest point on the line to any potentially colliding triangle. To deal with multiple contacts and non-convexities, the line is decomposed into segments and a dynamic point is used for each segment. The algorithm may be used to compute collision detection and response with rigid as well as deformable objects with no performance penalty. Realistic examples are presented to demonstrate the effectiveness of our approach.

Handling the evolving permanent contact of deformable objects leads to a collision detection problem of high computing cost. Situations in which this type of contact happens are becoming more and more present with the increasing complexity of virtual human models, especially for the emerging medical applications. In this context, we propose a novel collision detection approach to deal with situations in which soft structures are in constant but dynamic contact, which is typical of 3D biological elements. Our method proceeds in two stages: First, in a preprocessing stage, a mesh is chosen under certain conditions as a reference mesh and is spherically sampled. In the collision detection stage, the resulting table is exploited for each vertex of the other mesh to obtain, in constant time, its signed distance to the fixed mesh. The two working hypotheses for this approach to succeed are typical of the deforming anatomical systems we target: First, the two meshes retain a layered configuration with respect to a central point and, second, the fixed mesh tangential deformation is bounded by the spherical sampling resolution. Within this context, the proposed approach can handle large relative displacements, reorientations, and deformations of the mobile mesh. We illustrate our method in comparison with other techniques on a biomechanical model of the human hip joint.

In this paper, we present our spreadsheet framework, which uses a spreadsheet-like interface for exploring biomedical datasets. The principles and advantages of this class of visualization systems are illustrated, and a case study for the analysis of hip joint congruity is presented. Throughout this use case, we see how end users can compare different datasets, apply parallel operations on data, create analysis templates, and how this helps them in the exploration process.

The present paper describes the integration of a multi-finger haptic device with deformable objects in an interactive environment. Repulsive forces are synthesized and rendered independently for each finger of a user wearing a Cybergrasp force-feedback glove. Deformation and contact models are based on mass-spring systems, and the issue of the user independence is dealt with through a geometric calibration phase. Motivated by the knowledge that human hand plays a very important role in the somatosensory system, we focused on the potential of the Cybergrasp device to improve perception in Virtual Reality worlds. We especially explored whether it is possible to distinguish objects with different elasticities. Results of performance and perception tests are encouraging despite current technical and computational limitations.

This paper addresses evaluation and visualization of stress and strain on soft biological tissues in contact given three-dimensional models of reconstructed organs from magnetic resonance images (MRI), we use an anatomy-based kinematical model combined with a soft tissues model to represent their shape and behavior. Then, we compute resulting distribution of stress and strain on deforming surface when motion is simulated. The computed stress and strain are then effectively visualized using an interactive animation framework. Experimental results are illustrated in the case of the hip joint cartilage.

This paper describes a new joint model for articulated human skeletons. The model is based in human anatomy and was conceived for use in medical applications. In this model, we try to overcome some limitations of other models used in computer graphics. For validation, we compared a knee modeled by our approach with a simulator, a plastic model of a knee, and images taken during a video-arthroscopy.