The 3D Tune-In Toolkit (3DTI Toolkit) is an open-source standard C++ library which includes a binaural spatialiser. This paper presents the technical details of this renderer, outlining its architecture and describing the processes implemented in each of its components. In order to put this description into context, the basic concepts behind binaural spatialisation are reviewed through a chronology of research milestones in the field in the last 40 years. The 3DTI Toolkit renders the anechoic signal path by convolving sound sources with Head Related Impulse Responses (HRIRs), obtained by interpolating those extracted from a set that can be loaded from any file in a standard audio format. Interaural time differences are managed separately, in order to be able to customise the rendering according the head size of the listener, and to reduce comb-filtering when interpolating between different HRIRs. In addition, geometrical and frequency-dependent corrections for simulating near-field sources are included. Reverberation is computed separately using a virtual loudspeakers Ambisonic approach and convolution with Binaural Room Impulse Responses (BRIRs). In all these processes, special care has been put in avoiding audible artefacts produced by changes in gains and audio filters due to the movements of sources and of the listener. The 3DTI Toolkit performance, as well as some other relevant metrics such as non-linear distortion, are assessed and presented, followed by a comparison between the features offered by the 3DTI Toolkit and those found in other currently available open- and closed-source binaural renderers.

This paper explores the influence of passive haptic feedback on presence and task performance using two important interaction metaphors. We compared direct interaction with the user's hand with interaction using a stylus. Twenty-four participants performed a simple selection task consisting of pressing buttons while playing a memory game, with haptic feedback and interaction metaphor as the independent variables. We measured task performance by computing errors and time between button presses. We measured presence with questionnaires and through a new method based on users' involuntary movements. Our results suggest that passive haptic feedback improves both presence and task performance. However, small but significant differences related to the interaction metaphor were only apparent when haptic feedback was not provided.

Abstract. Good maintainability is an essential feature for machines and processes in industry. It promotes, among others, maintenance safety, postmaintenance reliability and cost-effective maintenance by ensuring quick and easy operation and short downtime. Virtual engineering tools provide an effective way for maintainability design already during the design phase. Machine designers may not consider maintenance tasks systematically, which can leave important task details open. The missing detail planning can contribute significantly to the probability of safety or reliability risks. So far, generic tools or facilities for planning demanding maintenance tasks in detail have not been available for companies' independent use. Another challenge is to develop and apply better user interfaces for design processes. Virtual engineering tools, such as virtual reality (VR) and haptics, provide a potential solution for improving maintenance planning and maintainability design. This paper introduces development and benefits of a new haptic interface for planning and training industrial maintenance tasks. The paper introduces a test with haptics tools in virtual maintenance case examples. As a conclusion we will sum up, whether the use of a haptic user interface would enhance task planning and maintainability design. In addition, we propose a set of recommendations regarding use of haptics in maintenance planning and maintainability design.

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In this chapter, an experimental study is presented for evaluating the importance of binocular disparity in depth perception within a Virtual Environment (VE), which is assumed to be critical in many manipulation tasks. In this research work, two assumptions are made: Size cues strongly contaminate depth perception mechanisms and binocular disparity optimizes depth perception for manipulation tasks in VE. The results outline size cues as possible cause of depth perception degradation and binocular disparity as an important factor in depth perception, whose influence is altered by the position within a VE.

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It is generally understood that virtual reality simulations have a high computational cost. Hence, they rarely can reduce completely all the incoherence within the cross-modal sensory outputs provided. The main research approaches to date have consisted in technically reducing possible mismatches, however minimal research has been conducted so as to analyse their influence on human capabilities. Thus, the objective of this study is to provide further insights to the designers of virtual reality about the negative influence of simulation lags and interesting design implications. To clearly show this, we have investigated the importance of coherent sensory feedback by incorporating time delays and spatial misalignments in the feedback provided by the simulation as a response to participant´s actions to mimic computationally expensive environments. We have also evaluated these misalignments considering two typical interaction setups. In particular, the sensory mismatches influence has been assessed in human factors, such as the sense of presence, task performance and delay perception. Our experimental results indicate that the closer the interaction conditions are to real configurations the higher the sensory requirements are regarding accuracy. The implications of this study offer the designer guidelines to prioritise the reduction of those mismatches in the sensory cues provided depending on the simulations goals.

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