基于OGRE引擎的虚拟场景浏览

虚拟现实技术的虚拟交互性得到了越来越广泛地应用,虚拟场景浏览技术有效地解决了现实世界的时空局限等瓶颈问题.在对虚拟现实(3I)原理研究分析的基础上,依据插件设计的思想,设计了一种基于OGRE引擎的虚拟场景浏览框架,框架明确的包含两个端:渲染端和控制端.渲染端封装了OGRE渲染引擎,实现了快速实时的渲染;控制端,通过建立虚拟漫游交互机制来完成虚拟场景与外设的实时控制.基于OGRE八叉树的场景管理、射线查询算法、寻路算法、物体的拣取、RTT等技术的运用实现了用户与虚拟环境的交互系统,用户操作信号输入到计算机中并作用于虚拟环境,创建实时渲染处理结构,实现人与虚拟环境的实时快速的交互;基于OpenAL,OggSound的音效系统,克服了用户在场景浏览时的单调与乏味,更具真实感,丰富了场景浏览的真实性.在实践中应用OGRE图形引擎、CEGUI界面库、OpenAL,OggSound声音库实现了该系统.     

虚拟现实技术概述

“虚拟现实”就是一种可以创建和体验虚拟世界的计算机系统。这种系统生成的各种虚拟环境,作用于用户的视觉、听觉、触觉,使用户产生身临其境的感觉,沉浸其中。而所谓虚拟世界则是虚拟环境或给定仿真对象的集合虚拟现实是近年发展起来的一项新技术,目前已广泛地应用于许多领域。该文阐述了虚拟现实技术的产生、概念、特征及其意义、虚拟现实技术的技术组成和艺术、情感魅力,分析了虚拟现实技术的研究内容、方向和技术瓶颈。     

基于VRML技术的虚拟产品可控性研究

虚拟现实（VR-virtual reality），也称虚拟实境或灵境，是一种可以创建和体验虚拟世界的计算机系统，它利用计算机技术生成一个逼真的、具有视、听、触等多种感知的虚拟环境。用户通过使用各种交互设备。同虚拟环境中的实体相互作用，使之产生身临其境感觉的交互式视景仿真和信息交流。是一种先进的数字化人机接口技术。 从本期专题可以看到：虚拟现实技术在机械行业有广泛的应用前景。虚拟设计对传统设计方法的革命性影响已经逐渐显现出来，虚拟现实技术与传统CAD／CAM技术的结合有着光辉的前景。     

基于Jack的虚拟维修样机交互行为建模方法研究

虚拟维修仿真是近年来出现的一种新的采用计算机动画、虚拟现实等技术,进行维修设计和维修训练等的方法,其基本思路是建立设备的虚拟样机,在虚拟环境中模拟特定的维修活动,如产品或部件的拆卸分解、更换、装配等;从运动行为建模、约束关系建模与拆装顺序描述3个方面详细讨论了虚拟样机交互行为建模的方法与过程,最后在Jack环境下设计了交互特征建模软件模块,利用数据库管理样机的交互特征;基于特征的交互行为模型能够满足虚拟维修仿真的需要,设计的软件模块能够较好地与仿真系统集成,对虚拟维修仿真实现具有重要意义.     

虚拟装配技术概述

基于现代制造业的现状和发展趋势,从市场的需求出发,在总结传统装配技术的基础上,详细地介绍了虚拟装配技术的相关理论和相关技术,如：虚拟现实、虚拟环境等。虚拟现实和虚拟环境为虚拟装配提供了逼真的、具有视、听、触、嗅、味等多种感知的虚拟仿真的场景,同样具有真实环境所有的特征。文章对虚拟装配的步骤、过程、分类及功能进行了系统地介绍,在现有知识的基础上,提出了更新的、更有实际意义的技术思想,总结了一般意义下虚拟装配的实现技术,得出虚拟装配的现实意义。     

基于虚拟现实技术的建筑施工动态仿真研究

建筑施工过程是一个极其复杂、高度动态的过程,容易受到各种因素的干扰。建筑物的内部结构纷繁复杂,又相互牵连制约,造成建筑施工存在时间和空间上的复杂的逻辑关系。本文基于虚拟现实技术利用3DS Max软件来模拟建筑施工的主要施工环节,实现在虚拟环境中的建筑施工过程的动态仿真,并利用Virtools虚拟交互软件完成交互设计,实现多角度、全方位观察建筑模型。这一研究对优化建筑设计和保障建筑施工安全将有较大的意义和促进作用。     

优秀的多体动力学虚拟仿真系统Vortex

一、前言 近十年来,随着计算机软硬件技术的飞速发展,在虚拟现实领域出现了许多高级的开发工具和硬件设备,大大提高了虚拟场景创建和虚拟环境中的人机交互等方面的能力.     

虚拟环境中履带式车辆运动仿真

为了对虚拟环境中履带车辆进行建模,满足虚拟现实系统沉浸感和实时性要求,研究了基于ODE(多体动力学仿真库)的履带式车辆多体动力学模型和仿真方法.将模型应用于虚拟现实系统,对履带车辆运动、翻越垂直墙、壕沟等障碍进行实时仿真.结果表明该模型能较好地表现虚拟环境中履带式车辆运动的动态过程,以及履带、负重轮等行走系统部件的相对运动.提出的模型及仿真方法能较好地应用于虚拟战场、装备模拟训练系统等虚拟环境,具有一定的应用价值.     

带有力感觉的显微外科手术血管的仿真研究

随着虚拟现实技术的进步,带有力感觉的仿真研究迅速发展,特别是在医学上得到了广泛应用。利用虚拟现实技术取代效率低下的常规培训,可以大大减少所需的培训时间和昂贵的动物实验费用。针对复杂的显微外科手术的血管缝合,作者建立了可用于大夫培训、手术规划的虚拟现实系统。其中的交互设备采用了具有力反馈功能的PHANTOM—Desktop,使用与之配套的GHOSTSDK软件开发包,建立虚拟环境。考虑到柔性体仿真的实时性和真实性要求,采用了质量一弹簧模型的建模方法。在完成了对虚拟环境中柔性平面仿真的基础上,成功实现了带有力感觉的显微外科血管穿刺的虚拟仿真。     

基于VRML构建室内虚拟环境的设计与实现

虚拟现实技术是目前国内外计算机应用研究的热点,其实时的三维空间表现力和逼真的沉浸感,将极大地推动计算机仿真技术的发展。该文详述了虚拟现实技术的主要特征及其应用,并介绍了虚拟现实建模语言VRML的基本格式和特点,讨论了基于VRML构建室内虚拟环境的常用技术。最后,利用支持VRML的3DSMAX软件实现了三维复杂物体建模,通过Java/Java Script实现了用户与室内虚拟环境之间的动态交互。     

Design evaluation and modification of mechanical systems in virtual environments

Design is one of the most important stages in the manufacturing cycle and influences all the subsequent stages of product development. In the context of today’s iterative design methodology, the modification of any design is a process involving many evaluations and improvements to the solutions chosen in earlier stages. For this purpose, in the most recent decade, 3D computer simulations have become common tools used within industry. Whilst virtual reality (VR) technology is seen as the interaction technology of the future, much of the current research in this area is carried out to explore the potential benefits and added value brought by the integration of this into standard software technologies currently used at various stages in manufacturing life cycle. A lot of attention has been given to exploring the usability and benefits of interactive VR for assembly planning, knowledge elicitation and design and simulation. However, little research has focussed on the analytical aspects of the design process, for example in the use of VR as an interface for simulation software in finite element methods and multi-body systems. This paper introduces research focussing on applications of virtual environments (VEs) for interactive design evaluation and modification adapted and used with standard simulation software. The use of such interactive visualisation offers the engineer more realistic real-time representations of the design and advanced facilities to interact with the model during the design process. While design evaluation is based mainly on visualisation; design modification requires interactive changes of the model during the simulation, and the interfaces described here highlights such applications. In this work, two software prototypes have been developed using VR technology. First, a software tool called design evaluation in virtual environments is presented together with an application in civil engineering to illustrate the mode of operation and added value of the use of an interactive visualisation environment. Linking the simulation software with the VE provides real time bi-directional communication of graphical information which can be successfully achieved even within the limits of current computer technology. The tool includes a suite of software modules and a user interface to facilitate the link between the simulation results and the VE. The second tool facilitates the design modification in virtual environments system by providing real time dynamic simulation. Two dynamic approaches are investigated in order to study the real time simulation issues in the context of design modification and system performance: the classic approach based on rigid interconnected bodies, and a new and novel approach developed by the authors based on particles dynamics. Both implementations have been tested and compared on a mechanism application under the same computing conditions. The research applications presented demonstrate the practicality, flexibility and versatility of the visualisation in virtual environment in design evaluation and modification. However, the computer efficiency whilst carrying out real time dynamic simulation is limiting the range of applications to models of moderate size; however, this is an improvement on previous similar applications.     

Reflecting on the Design Process for Virtual Reality Applications

A reflective analysis on the experience of virtual environment (VE) design is presented focusing on the human–computer interaction (HCI) challenges presented by virtual reality (VR). HCI design guidelines were applied to development of two VRs, one in marine archaeology and the other in situation awareness simulation experiments. The impact of methods and HCI knowledge on the VR design process is analyzed, leading to proposals for presenting HCI and cognitive knowledge in the context of design trade-offs in the choice of VR design techniques. Problems reconciling VE and standard Graphical User Interface (GUI) design components are investigated. A trade-off framework for design options set against criteria for usability, efficient operation, realism, and presence is proposed. HCI-VR design advice and proposals for further research aimed towards improving human factor-related design in VEs are discussed.     

Teaching your system to share

Creating multi-user virtual worlds is a relatively new challenge for developers of virtual reality applications. It is especially challenging to build networked VR systems based on inexpensive PC-based hardware, due to limitations in system software and inefficient networking hardware. This article explains how we created a multi-person shared virtual environment using DOS-based PCs. It also covers some of the design goals in creating a collaborative design tool for creating and modifying virtual buildings. Workroom is a general purpose simulation infrastructure that allows multiple participants to interact in unpredictable ways while minimizing simulation latency     

Integration of manufacturing services into virtual environments over the internet

Virtual reality (VR) is a rapidly developing technology that has a wide spectrum of industrial and commercial applications. Networked (distributed or shared) virtual environments (VE) are of growing interest to modern manufacturing industry; a dominating use of networked virtual manufacturing environments (VMEs) is on-line visualisation and collaborative control of 3D information. This has to be supported by real-time data transfer. To meet a broad range of common requirements for Internet-based VE communications, particularly for virtual manufacturing and collaborative design and control, this paper presents a networked virtual environment system that is designed to support networked virtual design and manufacturing. The system is implemented with manufacturing message specification (MMS) standards so as to integrate a range of manufacturing services into networked VEs over the Internet.     

The physiological mirror—a system for unconscious control of a virtual environment through physiological activity

This paper introduces a system for real-time physiological measurement, analysis, and metaphorical visualization within a virtual environment (VE). Our goal is to develop a method that allows humans to unconsciously relate to parts of an environment more strongly than to others, purely induced by their own physiological responses to the virtual reality (VR) displays. In particular, we exploit heart rate, respiration, and galvanic skin response in order to control the behavior of virtual characters in the VE. Such unconscious processes may become a useful tool for storytelling or assist guiding participants through a sequence of tasks in order to make the application more interesting, e.g., in rehabilitation. We claim that anchoring of subjective bodily states to a virtual reality (VR) can enhance a person’s sense of realism of the VR and ultimately create a stronger relationship between humans and the VR.     

虚拟现实在体育仿真中的应用综述

对基于虚拟现实的体育(训练)仿真技术的发展现状进行综述，讨论了体育仿真的关键技术，介绍了几个典型应用系统，最后对虚拟现实技术在体育训练仿真中的应用前景进行了讨论。     

Desktop haptic virtual assembly using physically based modelling

This research investigates the feasibility of using a desktop haptic virtual environment as a design tool for evaluating assembly operations. Bringing virtual reality characteristics to the desktop, such as stereo vision, further promotes the use of this technology into the every day engineering design process. In creating such a system, the affordability and availability of hardware/software tools is taken into consideration. The resulting application combines several software packages including VR Juggler, open dynamics engine (ODE)/open physics abstraction layer (OPAL), OpenHaptics, and OpenGL/GLM/GLUT libraries to explore the benefits and limitations of combining haptics with physically based modelling. The equipment used to display stereo graphics includes a Stereographics emitter, Crystal Eyes shutter glasses, and a high refresh rate CRT Monitor. One or two-handed force feedback is obtained from various PHANTOM haptic devices from SensAble Technologies Inc. The application’s ability to handle complex part interactions is tested using two different computer systems, which approximate the higher and lower end of a typical engineer’s workstation. Different test scenarios are analyzed and results presented.     

虚拟工厂现实场景系统平台设计与实现

随着现代化工业不断发展,模拟过程工业真实环境,并在此基础上进行地理信息显示与空间分析等成为当前的研究热点。构建基于虚拟现实(VR)和地理信息系统的(GIS)的虚拟工厂现实场景系统是进行工业生产仿真的一条有效途径,为此,设计开发一个三维的、可维护性强并具有一定扩展性的虚拟工厂现实场景系统具有重要的实用价值。本文通过数据准备、数据生成、系统扩展及客户端设计,实现了虚拟工厂现实场景系统开发过程。通过应用分析与对比,结果表明,该平台化系统具有更高的可扩展性且开发成本低,为虚拟工厂现实场景系统平台设计提供了一个良好的、可扩展的开发途径。     

基于VR和AR技术的工业产品包装工程设计研究

为了有效提高工业产品包装与产品的适应性,设计引入VR和AR技术,提出VRML工业产品包装工程设计方法。方法主要包括三个步骤,首先利用VR虚拟现实技术,在虚拟现实空间内,建立产品包装湍流模组,该模组主要用于求取与产品完全契合的包装内部数据,在VR技术的基础上应用AR增强现实,生成VRML虚拟交互空间,将虚拟空间节点进行覆盖连接,结合包装内部数据,生成工业产品包装虚拟外观,最后在虚拟空间内,对上述生成的产品包装细节层次和光照物化进行重新矫正,获取的最终结果即为包装工程最终设计结果'根据实验数据分析可以肯定,通过使用VRML工业产品包装工程设计方法,工业产品包装贴合度上升32%,抗压比提高了29%,证明该包装有效提高了产品抗震性能,具有重要使用价值。