Exploration Of Virtual Worlds Research Articles

Natural- and redirected walking in virtual reality: Spatial performance and user experience

AbstractImmersive virtual reality offers a range of unique possibilities. One of these is the realistic exploration of virtual worlds using natural walking. This however becomes difficult when the size of the virtual world exceeds that of the available physical space. Redirected walking in virtual reality presents a novel solution to this problem by typically making its users think to be walking in a straight line while they are in fact walking in a curve, thus allowing them to physically walk long distances in confined physical spaces. Yet, few studies have examined the effects of redirected walking on variables such as spatial memory, navigation and user experience as compared to other immersive and non-immersive locomotion methods. In a maze task we examined 1) redirected- and 2) natural walking in immersive virtual reality conditions, and 3) artificial locomotion on a non-immersive desktop monitor. Walked path lengths became shorter and distance estimates, object location memory and user experience improved using natural walking compared to a monitor condition. However, redirected walking yielded similar performance to natural walking while requiring less physical space, opening up possibilities for more pervasive use of real locomotion in virtual environments.

Mathematical Content Browsing for Print-disabled Readers Based on Virtual-world Exploration and Audio-visual Sensory Substitution

Documents containing mathematical content remain largely inaccessible to blind and visually impaired readers because they are predominantly published as untagged PDFs, which do not include the semantic data necessary for effective accessibility. Equations in such documents consist of text interlaced with lines and other graphical elements and cannot be interpreted using a screen reader. We present a browsing approach for print-disabled readers specifically aimed at such mathematical content. This approach draws on the navigational mechanisms often used to explore the virtual worlds of text adventure games with audio-visual sensory substitution for graphical content. The relative spatial placement of the elements of an equation are represented as a virtual world so the reader can navigate between elements. Text elements are announced conventionally using synthesised speech, while graphical elements, such as roots and fraction lines, are rendered using a modification of the vOICe algorithm. The virtual world allows the reader to interactively discover the spatial structure of the equation, while the rendition of graphical elements as sound allows the shape and identity of elements that cannot be synthesised as speech to be discovered and recognised. The browsing approach was evaluated by 11 blind and 14 sighted participants in a user trial that included identifying twelve equations extracted from PDF documents. Overall, equations were identified completely correctly in 78% of cases (74% and 83%, respectively, for blind and sighted subjects). If partial correctness is considered, then the performance is substantially higher. Feedback from the blind subjects indicated that the technique allows spatial information and graphical detail to be discovered. We conclude that the integration of a spatial model represented as a virtual world in conjunction with audio-visual sensory substitution for non-textual elements can be an effective way for blind and visually impaired readers to read currently inaccessible mathematical content in PDF documents.

CARE: A Collision-Aware Mobile Robot Navigation in Grid Environment using Improved Breadth First Search

In recent years, there is an increasing interest in designing autonomous vehicles such as Mobile Robots. However, one of the fundamental needs of Mobile Robots is a collision-free navigation with an optimal path from the source to the destination. In this paper, a collision-free low-complexity Mobile Robot navigation scheme called Collision Aware Mobile Robot navigation in Grid-Environment is designed. The proposed scheme uses the Radio Frequency based Identification method for Mobile Robot localization, the hybrid approach for the path planning, and a predefined decision table for the navigation. The algorithms are implemented in two stages, construction of virtual world and generation of optimal shortest path. The algorithms’ performance is analyzed in grid-based environment of size 5×5,20×20,35×35, and 50 × 50 with four different cases. It is observed that for the environment with no obstacles, the robot explores fewer cells in finding the shortest path. However, the number of turning in the shortest path is always less in the environment with some obstacles than in the case of whole virtual world exploration. The performance results show the effectiveness of the proposed scheme for Mobile Robot navigation in the grid environment.

Ecologically Sound Procedural Generation of Natural Environments

Current techniques for the creation and exploration of virtual worlds are largely unable to generate sound natural environments from ecological data and to provide interactive web-based visualizations of such detailed environments. We tackle this challenge and propose a novel framework that (i) explores the advantages of landscape maps and ecological statistical data, translating them to an ecologically sound plant distribution, and (ii) creates a visually convincing 3D representation of the natural environment suitable for its interactive visualization over the web. Our vegetation model improves techniques from procedural ecosystem generation and neutral landscape modeling. It is able to generate diverse ecological sound plant distributions directly from landscape maps with statistical ecological data. Our visualization model integrates existing level of detail and illumination techniques to achieve interactive frame rates and improve realism. We validated with ecology experts the outcome of our framework using two case studies and concluded that it provides convincing interactive visualizations of large natural environments.

The Universal Campus: An open virtual 3-D world infrastructure for research and education

The Universal Campus is a 3-D virtual world infrastructure consisting of a campus with multiple buildings and meetings rooms together with a set of avatars. The Universal Campus is built using a server-client architecture, with an OpenSim-based server and a Second Life-based client. The entire infrastructure is open and can be fully downloaded, replicated, shared, and customized. The Universal Campus enables the deployment and exploration of virtual worlds in research and education, in particular the deployment of meetings of various sizes, such as group meetings, classes, and conferences, in a 3-D virtual world where avatars can move around, view presentations, meet serendipitously, and engage in multiway communication supported by both chat and voice.

Application of Genetic Algorithm for Computing a Global 3D Scene Exploration

This paper is dedicated to virtual world exploration techniques, which have to help a human being to understand a 3D scene. A new method to compute a global view of a scene is presented in the paper. The global view of a scene is determined by a “good” set off points of view. This method is based on a genetic algorithm. The “good” set of points of view is used to compute a camera path around the scene.

Herramientas en 3D para el modelado de escenarios virtuales basados en logo: Estado del arte

Este artículo revisa la comprobada fundamentación pedagógica de LOGO (Papert,2003) que a su vez ofrece interesantes estrategias de motivación para los niños, en aspectos tales como el desarrollo de habilidades espaciales a través de su propia exploración de mundos virtuales. La metodología original fue propuesta por Seymour Papert para escenarios en dos dimensiones (2D). Por lo tanto, se analiza la posibilidad de integrar las ventajas pedagógicas de LOGO con una interfaz gráfica en tres dimensiones (3D), al aprovechar la tecnología contemplada en los estándares del consorcio Web3D. Además menciona los componentes X3D que permiten el uso de avatares (humanoides) para facilitar la interacción de los usuarios en mundos virtuales dinámicos, al disponer de personajes adicionales al de la tortuga de LOGO.

Virtual world explorations by using topological and semantic knowledge

This paper is dedicated to virtual world exploration techniques. Automatic camera control is important in many fields as computational geometry, visual servoing, robot motion, graph drawing, etc. The paper introduces a high-level camera controlling approach in virtual environments. The proposed method is related to real-time 3D scene exploration and is made of two steps. In the first step, a set of good viewpoints is chosen to give the user a maximum knowledge of the scene. The second step uses the viewpoints to compute a camera path between them. Finally, we define a notion of semantic distance between objects of the scene to improve the approach.

Enhancing the experience of 3D virtual worlds with a cartographic generalization approach

In this work we propose a new approach for fast visualization and exploration of virtual worlds based on the use of cartographic concepts and techniques. Versions of cartographic maps with different levels of details can be created by using a set of operations named cartographic generalization. Cartographic generalization employs twelve operators and domain-specific knowledge, being the contribution of this work their transposition to 3D virtual worlds. The architecture of a system for 3D generalization is proposed and the system is implemented. Differently from traditional cartographic processes, we use artificial intelligence for both selecting the key objects and applying the operators. As a case study, we present the simplification of the historical quarter of Recife (Brazil).

Methods and data structures for virtual world exploration

This paper is dedicated to virtual world exploration techniques that help humans to understand a 3D scene. The paper presents a technique to calculate the quality of a viewpoint for a scene, and describes how this information can be used. A two-step method for an automatic real-time scene exploration is introduced. In the first step, a minimal set of “good” points of view is determined; in the second step, these viewpoints are used to compute a camera path around the scene. The proposed method enables one to get a good comprehension of a single virtual artifact or of the scene structure.