ESPINA is an image segmentation tool designed to analyse microscopy images in order to identify neuronal structures and to produce 3D models of these structures. This tool allows to display three-dimensional volumes using auto-stereoscopic monitors. It was initially designed for workstations, but when data volume management or its processing complexity makes unfeasible the implementation of the new tools on these computers, it is necessary to resort to computing servers that delimit response times or by means of scalable solutions and algorithmic optimizations. This paper analyses the migration of this tool from the original implementation to a scalable solution and describes the experience achieved during the development of the workstation version. The proposed alternative is a distributed version of the tool that delegate heavy-computational processes to a cluster, improving the performance of the system in a master/slave architecture.

In mobile machine industry, work machine simulators can be used to save time and costs in product development and training. However, investing into expensive or difficult-to-use technology should be avoided if it does not affect measurable user performance or feeling of presence. At Tampere University of Technology, a virtual loader simulator has been constructed in an three-wall walk-in virtual environment. The goal of this research was to investigate how the immersivity of the simulator affects testers’ feeling of presence. A total of 25 test users performed two test runs each with different simulator setups, and the presence level of each user was evaluated by a questionnaire after both runs. The results indicate that switching from 2D view to 3D stereoscopic display did not significantly affect the sense of presence. However, with the motion platform, the test users reported clearly higher presence ratings than without it. In addition, we examined some effects of the users’ backgrounds: Test users who had experience from driving large work machines reported lower presence ratings than those without such experience. The sense of presence for frequent computer players was higher than for non-players, but only in one simulator setup.

With the proliferation of large screen stereo display systems, major consumer product manufacturers are using this technology to test marketing ideas on consumers. One of the performance factors that is of interest to retailers or manufacturers of retail products is the ability of consumers to quickly and easily locate their products within a retail store. Virtual reality technology can be used to create a virtual store that is easily reconfigurable as a test environment for consumer feedback. The research presented in this paper involves a study that compares the use of a multi-wall immersive environment to a single-wall immersive environment. Users were given a list of products to find in the virtual store. A physical mockup of a shopping cart was created and instrumented in order to be used to navigate throughout the virtual store. The findings indicate that participants in the five-wall immersive environment were significantly faster in locating the objects than the participants using the one-wall immersive environment. In addition, participants in the five-wall condition reported that the shopping cart was easier to use than in the one-wall condition. This study indicates that the use of multiple walls to provide an increased sense of immersion improves the ability of consumers to locate items within a virtual shopping experience.

Interacting with computers by using the bodily motion is one of the challenging topics in the Virtual Reality field, especially as regards the interaction with large scale virtual environments. This paper presents a device for interacting with a Virtual Reality environment that is based on the detection of the muscular activity and movements of the user by the fusion of two different signals. The idea is that through muscular activities a user is capable of moving a cursor in the virtual space, and making some actions through gestures. The device is based on an accelerometer and on electromyography, a technique that derives from the medical field and that is able to recognize the electrical activity produced by skeletal muscles during their contraction. The device consists of cheap and easy to replicate components: seven electrodes pads and a small and wearable board for the acquisition of the sEMG signals from the user’s forearm, a 3 DOF accelerometer that is positioned on the user’s wrist (used for moving the cursor in the space) and a glove worn on the forearm in which these components are inserted. The device can be easily used without tedious settings and training. In order to test the functionality, performances and usability issues of the device we have implemented an application that has been tested by a group of users. Specifically, the device has been used as natural interaction technique in an application for drawing in a large scale virtual environment. The muscular activity is acquired by the device and used by the application for controlling the dimension and color of the brush.

This paper presents a virtual experimental environment for testing virtual prototypes of intelligent mechatronic systems. A virtual prototype is a computer internal model of a real product. Virtual environments are used to verify the functionality of these virtual prototypes during the product development process. But normally, the virtual environments are composed manually. Engineers model the set of virtual prototypes and the relations between them manually. Furthermore, a lack of formal test methods exists for testing virtual prototypes of mechatronic systems. This paper presents software agents, which detect relations between virtual prototypes in a virtual environment, automatically. The concept of the agent-supported virtual environment is presented as well as the data needed by the agents for identifying relations between the virtual prototypes. The concept has been tested. One of the examples is described.

This paper investigates the effect of pointshell shrinking and feature size on manual assembly operations in a virtual environment with haptic force feedback. Specific emphasis is on exploring methods to improve voxel-based modeling to support manual assembly of low clearance parts. CAD parts were created, voxelized and tested for assembly. The results showed that pointshell shrinking allows the engineer to assemble parts with a lower clearance than without pointshell shrinking. Further results showed that assemble-ability is dependent on feature size, particularly part diameter and clearance. In a pin and hole assembly, as the pin diameter increases, for a given percent clearance, assembling low clearance features becomes difficult. An empirical equation is developed to guide the designer in selecting an appropriate voxel size based on feature size. These results advance the effort to improve manual assembly operations via haptic feedback in the virtual environment.

Haptic rendering has opened a new range of virtual reality applications, enabling a human user to interact with a virtual world using the sense of touch. This kind of interaction enables to enhance applications such as computer-assisted design, where 3D manipulations are part of the system. However, building an application with an accurate haptic feedback is still challenging, especially for interactions between rigid bodies, where stiff contacts can only be displayed with a high simulation frequency. This paper presents the possibilities of implementation of a modular haptic display system that relies on two main components: a physical simulation part and a haptic rendering part. For that purpose, we define a generic coupling approach that enables to perform haptic rendering using admittance haptic devices, through a scaling interface that cleanly separates the physical simulation and the haptic rendering system of units. Four physical simulation libraries are evaluated with respect to haptic rendering quality criteria, based on their behavior in four discriminant test cases. We show that the proposed approach leads to a modular, generic and stable haptic application.

Virtual reality (VR) environments based on interactive rendering of 3D computer graphics often incorporate the use of position and orientation tracking on the user’s head, hands, and control devices. The Wii Remote game controller is a mass-market peripheral that can provide a low-cost source of infrared point tracking and accelerometer data, making it attractive as a PC-based virtual reality head tracking system. This paper describes the development of an extension to the Virtual Reality Peripheral Network (VRPN) software to support the use of the Wii Remote game controller as a standard tracker object in a wide range of VR software applications. This implementation permits Wii Remote-based head tracking to directly substitute for more costly commercial trackers through the VRPN and VR Juggler Gadgeteer tracker interfaces. The head tracker provides up to 100Hz of head tracking input. It has been tested in a variety of VR applications on both Windows and Linux. The discussed solution has been released as open-source software.

In this paper we briefly describe an approach for understanding the psychoacoustic and perceptual effects of what we have identified as the high-level spatial properties of 3D audio. The necessity of this study is firstly presented within the context of interactive applications such as Virtual Reality and Human Computer Interfaces. As a result of the bibliographic research in the field we identified the main potential functions of 3D audio spatial stimulation in interactive applications beyond traditional sound spatialization. In the same sense, a classification of the high-level aspects involved in spatial audio stimulation is proposed and explained. Immediately, the case of study, the experimental methodology and the framework are described. Finally, we present the expected results as well as their usefulness within the context of a larger project.

Virtual Reality (VR) allows engineers to naturally interact with three-dimensional digital models in a three-dimensional space. This provides a unique interface between users and computer models not found in traditional desktop environments. Common uses of virtual reality in product design include prototype evaluation, virtual assembly and visualization of engineering analysis results. This work described in this paper is based on a methodology for interactive design that uses virtual reality as an interface to product design and analysis. Computer analysis models coupled with fast reanalysis approximations and geometric models in a virtual environment are developed to facilitate shape design changes and updated analysis results in real-time. This combined design and analysis environment encourages the rapid investigation of many possible shape and design changes and how they affect the final product performance. The application developed to test this methodology is referred the Immersive Virtual Design Application (IVDA).

The promise of Virtual Reality in design environments is to facilitate the interaction with digital models and to enhance the results of design activity. Design education is one of the most recent and interesting applications. Thanks to technological advances in human-computer interfaces, Virtual Reality represents a new way to stimulate design students and to develop innovative teaching methods. The paper explores the impact of Virtual Reality technologies on design learning, with particular attention to mechanical product design. It is focused on the analysis of cognitive and technical aspects of learning processes and the definition of a proper evaluation protocol. The protocol is based on the classification of the most meaningful activities in mechanical engineering teaching and the identification of a set of metrics that enable to objectively evaluate the learning process. Assessing how VR supports design education, an experimental study is proposed. It is based on the comparison of three different approaches performed by two-dimensional drawings, by 3D CAD models and, finally, by virtual reality technologies.

Implementation of tangible virtuality means providing means for creating airborne visual images, rendering them with physical properties and making them sensible for the human senses. Airborne creation and direct manipulation requires separating the virtual objects from the image generating (physical rendering) device. One step in this direction is using electroholographic, or pseudo-electroholographic, devices which are able to create virtual objects in mid-air by various light interference techniques. A virtual object is a computer model, visualized by the projection system to appear as a real, tangible object. Te enable the required direct interaction with the virtual objects these have to be perceptually separated from the projected device, they have to be perceived as floating in the air. In our research we use the Holovizio Hv128WD system, a mono-parallax, high resolution holographic imaging device supporting 3D image visualization rather than physical rendering of virtual objects. The device generates 62 views of virtual objects where each view is visible from a specific viewing direction. The user of the system perceives this as a stereo view to the object. We have been collecting application experiences related to this device for more than one year, and we have found some restrictions and limitations in the image creating capabilities which we are trying to eliminate in our current research. This paper reports on the first phase of research which focuses on some major image generation problems and exploration of possible hardware, software or data management causes. The goal of this first phase is to develop and validate the proper measurement methods. A pilot experiment is performed to verify the applicability of the method. The results show that the proposed measurement methods are feasible and helpful in analyzing the observed problems. Some problems appear to have a more fundamental cause and may only be worked around.

In this paper, we solve the force model and 3D fluid dynamics solver for surgical simulation designs by taking a combination of a cubic interpolated fluid solver and the advantage of the parallelism and programmability of GPU. In comparison to other methods, we present innovation in tree aspects. First, force models in haptic for fluid interactions is generated by GPU-CPU message passing scheme to get rapid development of haptic feedback modes for fluid dynamic data. Second, rapid solution in fluid dynamic solvers is developed by applying cubic interpolated propagation method. This method only split Navier-Stokes equations (NSEs) into advection and non-advection equation to generate immediate fluid dynamic solvers. To get more acceleration in the computation, we pack these equations into channels of texels. Third, beside we take advantage of the parallelism and programmability of the GPU where computation models are performed on pixels that can be considered to be a grid of cells, the CPU-GPU balancing is included; therefore, despite of the complexity of the anatomical geometry, processing on multiple vertices and pixels can be done simultaneously in parallel. The data are also passed to CPU to control the haptic in providing kinesthetic interaction and felling. These strategies provide effective enough to simulate fluid dynamic model for real-time interaction in 3D computer graphic for PC platform. Our experimental tests prove that fluid flowing on various obstacles with haptic interactions on the human anatomical model can be effectively and efficiently simulated on the reasonable frame rate with a realistic synthetic visualization.

This paper presents a scenegraph animation application programming interface (API), known as the Animation Engine, which was constructed for software developers to easily perform smooth transitions and manipulations to scenegraph nodes. A developer can use one line of code to enter the property, end state and number of frames to describe the animation, then the Animation Engine handles the rest in the background. The goal of the Animation Engine is to provide a simple API that integrates into existing applications with minimal effort. Additionally, techniques to improve virtual reality (VR) application performance on a large computer cluster are presented. These techniques include maintaining high frame rates with 4096 × 4096 pixel textures, eliminating extraneous network traffic and reducing long model loading time. To demonstrate the Animation Engine and the development techniques, an application known as the Virtual Universe was created. The Virtual Universe, designed to run in a six walled CAVE, allows users to freely explore a set of space themed environments. The architecture and development techniques for writing a stable immersive VR application on a large computer cluster, in addition to the creation of the Animation Engine, is presented in this paper.