Carolina Cruz-Neira

Analyzing the performance of a cluster-based architecture for immersive visualization systems

Cluster computing has become an essential issue for designing immersive visualization systems. This paradigm employs scalable clusters of commodity computers with much lower costs than would be possible with the high-end, shared memory computers that have been traditionally used for virtual reality purposes. This change in the design of virtual reality systems has caused some development environments oriented toward shared memory computing to require modifications to their internal architectures in order to support cluster computing. This is the case of VR Juggler, which is considered one of the most important virtual reality application development frameworks based on open source code. This paper not only describes in detail the mechanisms based on cluster computing included in the internal design of VR Juggler, but also proposes a new global performance evaluation methodology. The goal of this methodology is to test the graphical performance of immersive visualization systems based on clusters of computers in terms of both network latency and number of nodes in the cluster. In this sense, a performance evaluation of VR Juggler, both in an overall and a modular approach, is presented. The obtained results show that VR Juggler can be considered as an efficient tool to support immersive visualization systems on a cluster of computers.

Beyond desktop point and click: Immersive walkthrough of aerospace structures

There are a number of 3D applications that have shown the benefits of using visualization techniques for virtual prototyping and education in aerospace engineering. However, these applications typically run only on desktop computers and user interaction is limited to mouse and keyboard. Virtual reality technologies provide a richer set of user experience by combining stereoscopic images with interactive, multi-sensory, and viewer-centered environments. We present an interactive and immersive walk-through application of a space station that can be configured and executed on multiple operating systems and platforms. The hardware setup may vary for each platform. Some may be fully immersive environments with multiple projection screens that surround the user and provide spatial tracking, while others may only provide a single PC equipped with active stereo graphics output. Even a laptop using only monoscopic images is supported. The application has been tested in our omni-directional treadmill system, which includes spatial tracking of the users head and is run on a graphics cluster which drives three projection screens around the treadmill. This kind of immersion using stereo projection and correctly scaled structures allows for a better sense of spatial relationships, because users receive bio-mechanical feedback during navigation by walking. For computer desktop setups, the software can be configured to run on a single screen and with a game controller for navigation.

Online Software Maintenance for Mission-Critical Systems

Online software maintenance (OSM) is performed while an application is running. It requires transforming the runtime state of the application to go along with updates of its software. The goal is to perform maintenance of mission-critical systems while they continue to run. This research presents dynamically evolvable C++ classes as a way to enable OSM. The associated implementation mechanism is called the OSM framework. We provide a high-level view of the OSM framework and then describe different types of object-oriented design transformations that are supported. The accompanying state transformations are described to evolve the live objects along with the software. We have implemented a prototype of the OSM framework; it works with the g++ and the Microsoft C++ compilers. Performance results are presented to assess the memory and processing overheads of the OSM framework. The proposed approach advances the state of the art in two ways: (a) it extends the notion of dynamic evolvability by including fission and fusion and other object-oriented design transformations, and (b) it provides a novel OSM framework that takes advantage of C++ templates

An affordable surround‐screen virtual reality display

Abstract— Building a projection-based virtual reality display is a time-, cost-, and resource-intensive enterprise, and many details contribute to the final display quality. This is especially true for surround- screen displays where most of them are one-of-a-kind systems or custom-made installations with specialized projectors, framing, and projection screens. In general, the costs of acquiring these types of systems have been in the hundreds and even millions of dollars, specifically for those supporting synchronized stereoscopic projection across multiple screens. Furthermore, the maintenance of such systems adds an additional recurrent cost, which makes them hard to afford for general introduction in a wider range of industry, academic, and research communities. A low-cost easy-to-maintain surround-screen design based on off-the-shelf affordable components for the projection screens, framing, and display systems is presented. The resulting system quality is comparableto significantly more expensive commercially available solutions. Additionally, users with average knowledge can implement this design, and it has the added advantage that single components can be individually upgraded based on necessity as well as available funds.

V-Volcano: Addressing Students' Misconceptions in Earth Sciences Learning through Virtual Reality Simulations

Research in teaching and learning about Earth Sciences indicates that first year geology students not only lack knowledge about basic concepts, but that they may also have developed their own potentially incorrect explanations of those phenomena. Understanding volcanic concepts is one of the areas in which noticeable misconceptions occur, as a significant number of students seem to acquire their knowledge from non-traditional sources such as sensationalist media and catastrophic films. This paper presents V-Volcano, a virtual reality volcano activity learning environment that immerses students in a scientifically-accurate simulation of volcanic systems. Students are able to generate and manipulate volcanic eruptions in real-time with data monitoring to explore the effects of changing conditions. The goal is to provide a geoscience tool that can be used to correct student misunderstandings about volcanic phenomena.

Louisiana: a model for advancing regional e-Research through cyberinfrastructure

Louisiana researchers and universities are leading a concentrated, collaborative effort to advance statewide e-Research through a new cyberinfrastructure: computing systems, data storage systems, advanced instruments and data repositories, visualization environments and people, all linked together by software programs and high-performance networks. This effort has led to a set of interlinked projects that have started making a significant difference in the state, and has created an environment that encourages increased collaboration, leading to new e-Research. This paper describes the overall effort, the new projects and environment and the results to date.

An integrated pipeline to create and experience compelling scenarios in virtual reality

One of the main barriers to create and use compelling scenarios in virtual reality is the complexity and time-consuming efforts for modeling, element integration, and the software development to properly display and interact with the content in the available systems. Still today, most virtual reality applications are tedious to create and they are hard-wired to the specific display and interaction system available to the developers when creating the application. Furthermore, it is not possible to alter the content or the dynamics of the content once the application has been created. We present our research on designing a software pipeline that enables the creation of compelling scenarios with a fair degree of visual and interaction complexity in a semi-automated way. Specifically, we are targeting drivable urban scenarios, ranging from large cities to sparsely populated rural areas that incorporate both static components (e. g., houses, trees) and dynamic components (e. g., people, vehicles) as well as events, such as explosions or ambient noise. Our pipeline has four basic components. First, an environment designer, where users sketch the overall layout of the scenario, and an automated method constructs the 3D environment from the information in the sketch. Second, a scenario editor used for authoring the complete scenario, incorporate the dynamic elements and events, fine tune the automatically generated environment, define the execution conditions of the scenario, and set up any data gathering that may be necessary during the execution of the scenario. Third, a run-time environment for different virtual-reality systems provides users with the interactive experience as designed with the designer and the editor. And fourth, a bi-directional monitoring system that allows for capturing and modification of information from the virtual environment. One of the interesting capabilities of our pipeline is that scenarios can be built and modified on-the-fly as they are being presented in the virtual-reality systems. Users can quickly prototype the basic scene using the designer and the editor on a control workstation. More elements can then be introduced into the scene from both the editor and the virtual-reality display. In this manner, users are able to gradually increase the complexity of the scenario with immediate feedback. The main use of this pipeline is the rapid development of scenarios for human-factors studies. However, it is applicable in a much more general context.

Echtzeitaspekte von VR-Systemen

Der Begriff „Echtzeit“ beschreibt die Fahigkeit eines Computersystems (oder hier VR-Systems) Ergebnisse zeitlich vorhersagbar, und damit in konstanten, definierten und in der Regel moglichst kurzen Zeitabstanden zu liefern. Echtzeitfahigkeit ist eine der hartesten Anforderungen an VR-Systeme: Nutzer erwarten, dass ein VR-System Auswirkungen von Interaktionen ohne wahrnehmbare Verzogerungen erlebbar macht. Gegenstand dieses Kapitels sind ausgewahlte Themen, welche die Echtzeitfahigkeit von VR-Systemen betreffen. Im ersten Teilkapitel wird in einer Gesamtsicht auf VR-Systeme dargestellt, welche Arten von Verzogerungen (Latenzen) zwischen Nutzereingaben und der Systemreaktion auftreten. Es wird auch darauf eingegangen, wie Latenzen der Teilkomponenten von VR-Systemen abgeschatzt bzw. gemessen werden konnen. Das zweite Teilkapitel stellt gangige Methoden fur die effiziente Kollisionserkennung vor, z. B. den Einsatz von Hullkorpern und die Aufteilung des Kollisionserkennungsprozesses in Phasen unterschiedlicher Genauigkeit. Das dritte Teilkapitel beschaftigt sich mit Echtzeitaspekten beim Rendering von Virtuellen Welten.

Guest Editor's Introduction: Special Section on the IEEE Virtual Reality Conference (VR)

The three papers in this special section are expanded versions of the three best papers from the IEEE VR 2008 proceedings.