虚拟战场中不规则物体的实时显示研究

虚拟战场中不规则物体的实时显示能够增强人们在虚拟环境中的沉浸感。文中论述了在实时性要求很高的某型车辆视景仿真系统中,应用粒子系统方法构建简单模型实现爆炸效果的具体步骤,并提出了提高算法实时性的技巧,此方法已应用于仿真系统中,在一般配置的微机上实现20f/s的刷新率,模拟效果逼真,同时满足了系统实时性。     

虚拟战场中不规则物体的实时显示研究

虚拟战场中不规则物体的实时显示能够增强人们在虚拟环境中的沉浸感.文中论述了在实时性要求很高的某型车辆视景仿真系统中,应用粒子系统方法构建简单模型实现爆炸效果的具体步骤,并提出了提高算法实时性的技巧,此方法已应用于仿真系统中,在一般配置的微机上实现20f/S的刷新率,模拟效果逼真,同时满足了系统实时性.     

基于Vega的虚拟战场环境中特效仿真研究

在简单介绍了Vega的特效模块后,运用Vega的特效模块模拟了坦克在虚拟战场环境中开火时的爆炸烟火特殊视觉效果,并重点讨论了Vega的特效模块自定义粒子系统的基本属性及仿真运用。实践证明,利用Vega进行虚拟战场环境中特效的可视化仿真不仅方便快捷,而且效果较好。     

基于通用粒子系统模型的虚拟战场特效设计

该文总结了基于粒子系统的战场特效仿真方法,通过对粒子系统建模过程的分析,抽取战场特效的共同特性,设计了一个由粒子发射器、粒子、属性修改器和渲染器组成的通用粒子系统模型。并通过该模型对虚拟战场的常见特殊效果进行仿真。     

虚拟三维战场环境生成系统的设计与实现

虚拟战场环境是军事仿真应用的可视化平台.虚拟三维战场环境生成系统是能够通过可视化界面,根据军事仿真演练的要求,实时定制虚拟战场环境的工具.文章介绍了系统各模块的功能及实现方法,包括基于Creator的建模模块、基于Vega的模型驱动管理模块、基于粒子系统的特效和气象现象生成模块、地形编辑模块、虚拟战场环境中的视点切换和多通道生成模块以及人机交互模块.应用结果表明,该系统能产生符合要求的虚拟战场环境.     

基于粒子系统的战场环境特效仿真中云的模拟

基于粒子系统的特殊效果仿真是虚拟战场可视化仿真中的一个重要环节。本文以战场环境仿真为目的,阐述了粒子系统的原理,对自然环境中的云的物理特征进行了描述与分析,提出了基于粒子系统原理云模拟过程中的简化思路与模型,对云的动态方程进行改进分析,最终在Vega中根据简化模型实现了云的三维特殊效果仿真,并成功将其方法运用于某战场环境仿真系统中,最后给出了独立云团的效果图以及使用本文所研究的方法所得到的某战场环境仿真效果图。     

基于粒子系统的虚拟战场环境特殊效果模拟

作战系统在军事训练和军事演习的应用上具有经济性、科学性、实时性、交互性等其他训练模式无法比拟的优点,能够提高军事训练的效率,减少训练的成本,增加战士在训练过程中的安全性。虚拟战场环境是作战系统的一个非常基础的平台,值得研究探讨。在虚拟战场环境模拟中,对不规则动态形状物体建模的最有效的方法是粒子系统。而文中深入研究了粒子系统的基本原理,应用粒子系统的方法构建了一个战场爆炸模型来实现爆炸效果的具体实现过程,并分析爆炸粒子所受的动力来建立爆炸粒子的物理模型。实验结果表明这一模拟方法简单有效,逼真度和实时性效果较好。     

虚拟战场环境中地物的生成

在分布式交互仿真中,虚拟战场环境的质量极大地影响了训练的逼真度,而地物是影响虚拟战场环境质量的重要因素.但是在实际应用中地物的生成方式不够灵活、高效,操作上也不够方便.为了达到快速生成虚拟战场环境的目的,设计了地物生成模块,该文给出了虚拟战场环境中地物的详细分类,并介绍了地物生成的技术,给出了地物生成模块中参数的具体定义和地物生成的实现方式.该模块已经应用到装甲兵装备作战仿真实验室的建设中,收到良好的效果.     

可漫游的虚拟战场环境建模与实现

虚拟战场环境是军用仿真的一个重要基础平台,构造可漫游的虚拟战场场最是军用仿真中最基本的、必不可少的一个环节,广泛应用于战场模拟,作战训练和电脑游戏等方面。论文在简单介绍了构造虚拟战场场景的一般性步骤后,重点讨论了地形、自然现象等关键技术及漫游控制的实现等,论文在分析粒子系统的一般实现原理的基础上,提出了提高粒子系统算法实时性的一些技巧。实践证明,所实现的虚拟战场场景在实时性与真实感方面均取得了不错的效果。     

虚拟三维战场环境编辑器的设计与实现

快速准确地在分布式虚拟对抗演练中,根据战术想定的要求设定三维战场环境,是有效实现对抗演练的重要手段。虚拟三维战场环境编辑器是能够通过可视化界面,根据军事仿真演练的要求,实时定制虚拟战场环境的工具。该文介绍了该编辑器在分布式虚拟对抗演练中的重要地位,以及组成该编辑器的功能模块,并对各功能模块分别进行了介绍。同时也对用于编辑器中的雨、雪效果生成技术和屏幕拾取技术进行了阐述。     

虚拟战场环境中的态势标绘与表现

针对军事指挥所现状,设计并实现了一个态势标绘系统,能提供在电子地图上的二维标绘和在虚拟战场环境中的三维标绘两种标绘手段。重点讨论了三维态势标绘中涉及到的地形高程匹配、碰撞检测与碰撞响应、特殊信息和特殊效果的表现等关键技术,并提出了一种二维标绘和三维标绘的实时转换方法,从而实现了二维态势与三维态势的联动表现。     

A domain-oriented end-user design environment for generating interactive 3D virtual chemistry experiments

Three-dimensional virtual worlds are potentially feasible for building virtual educational environments. However, educators face technical challenges to apply these technologies because creating virtual educational environments based on virtual worlds demands 3D modeling and programming skills. This paper proposes a method to lower the technical barriers through domain-oriented interfaces with languages and environments that are familiar to educators. A domain-oriented end-user design environment, iVirtualWorld, is designed and developed to implement the proposed method in a specific educational domain, namely introductory chemistry experiments. This web-based environment provides end-users with domain-oriented building blocks, which can be assembled to create 3D virtual chemistry experiments. A usability evaluation and a comparative case study are designed to evaluate the system among chemistry educators, who are the target audience. The usability evaluation contains a task requiring participants to create a 3D virtual chemistry experiment and a voluntary semi-structured interview. The case study compares a virtual experiment generated using iVirtualWorld with an experiment in a commercial virtual chemistry laboratory system. The results show that 1) the domain-oriented end-user design environment enables participants to generate the 3D virtual chemistry experiment within 30 min; 2) participants gain confidence on creating 3D virtual experiments by themselves using iVirtualWorld; 3) participants confirm the usefulness of applying the system in introductory chemistry education; and 4) iVirtualWorld is considered more intuitive and straightforward for students to focus on finishing the experiment without being distracted than the commercial virtual chemistry laboratory system. Areas that can benefit from the system most and areas where the system is less effective are identified by participants. The responses also reveal the limitations of the current system and suggest directions for future improvement.     

宽广视野虚拟环境漫游的设计与实现

探讨了宽广视野三维虚拟环境沉浸式漫游的系统结构和若干技术问题.系统使用多台微机及配套图形卡构成集群并行渲染,使用MPI(message passing interface)构成消息递送环境,使用开放源码的OGRE(open graph rendering engine)三维图形引擎进行场景渲染.实验证明系统开发成本低、效果满足应用需求,可广泛用于训练模拟、飞行再现、虚拟战场环境等视景仿真领域.     

The nauseogenicity of two methods of navigating within a virtual environment

This study compared the nauseogenicity of two different strategies for exploring virtual environments whilst wearing an immersive head-mounted display. In the first, the head was kept still and movement was achieved solely by manipulating a hand-control. In the second, the subject was free (and encouraged) to move his or her head when exploring the virtual world. Fourteen subjects completed both of the 20 min trials, three further subjects withdrew from the study after one trial. Subjects reported increases in adverse symptoms when using each strategy and, for the group as a whole, nausea increased steadily during each immersion period. However, significantly larger changes were reported when the head moved than when it was still, as predicted from sensory conflict theory.     

接收点移动的室外虚拟声场模拟研究与应用

声线跟踪算法是一种目前较为流行的基于几何声学声场模拟算法,但该方法依赖于特定接收点的位置,因此不能直接用于接收者处于不断移动状态的虚拟环境中。对此,提出一种步长法动态定义接收点位置的改进声线跟踪算法,有效解决了声场仿真中听音效果与计算效率的冲突问题,尤其适合于大规模室外虚拟环境中声场的模拟研究。并用Visual Studio2005和Matlab工具完成程序设计和结果处理,达到满意的听音效果和计算效率。     

虚拟人环境感知的仿真方法研究

针对目标驱动的追击问题,将视线升维为柱体的视线筒,提出了一种虚拟人环境感知的筒视线方法.根据虚拟人所处的环境和行进速度,以变频方式、周期性地向目标发射筒视线,根据该筒视线与环境中障碍物的各碰撞点的信息和预先设置的行动推理知识库,确定虚拟人的追逐行动;为不完全可知的、动态虚拟环境中的目标追击问题提供了一种新的解决方案.该方案抛开了基于传统视野范围的拟人方式,以通过性的感知为中心,形成虚拟世界的互动性感知标准,建立虚拟人自身的感知功能,取得了更加逼真的仿真效果.原型系统验证了该方法的可行性和有效性.     

vSocial: a cloud-based system for social virtual reality learning environment applications in special education

Virtual Learning Environments (VLEs) are spaces designed to educate student groups remotely via online platforms. Although traditional VLEs have shown promise in educating students, they offer limited immersion that overall diminishes learning effectiveness. In this paper, we describe vSocial, a cloud-based virtual reality learning environment (VRLE) system that can be deployed over high-speed networks using the High Fidelity “social VR” platform. vSocial provides flexible control of group learning content and compliance with established VLE standards with improved immersive user experience for both instructor(s) and students. For our vSocial development, we build upon the use case of an existing special education VLE viz., iSocial that trains youth with Autism Spectrum Disorder by implementing the Social Competence Intervention (SCI) curriculum. The vSocial can be used to: (a) implement multiple learning modules using wearable VR technologies, (b) integrate cognitive state sensing devices, and (c) organize learning session data securely using web applications hosted on cloud resources. Our experiment results show that the VR mode of content delivery in vSocial better stimulates the generalization of lessons to the real world than non-VR lessons, and provides improved immersion when compared to an equivalent desktop version. Further, usability study results show that users can successfully use the web application features in vSocial for group learning activities with ease-of-use and consistency.

     

Deception in avatar-mediated virtual environment

This study explored the effects of avatars on deception – how perceived avatar likeness to self can affect the truthfulness and accuracy of interactions online. More specifically, this study examined the extent to which perceived avatar similarity influences self-awareness and users’ degree of attraction to them, and how these psychological states affect deception in the context of Second Life. The results, based on web-based survey data of 159 Second Life users, revealed that avatar similarity in attitude and behavior to the owner heightened self-awareness, which, in turn, reduced deception. Perceived avatar similarity in terms of appearance was found to have a direct negative impact on deception so that those who perceived their avatars to look similar to themselves were less likely to engage in deceptive behavior. Implications of the findings are discussed.     

分布式集成化作战建模环境研究

要解决作战模拟系统中军事领域专家与仿真技术专家之间的沟通问题,保证军事领域的战争系统模型和仿真领域的仿真实现模型描述的一致性,就必须建立对真实世界一致性描述模型,分布式集成化作战建模环境正是构建上述一致性描述模型所必需的软件系统。将对集成化作战建模环境进行研究,并提出一个切实可行的构架方案。