Realization of reconfigurable virtual environments for virtual testing

1 Introduction The scalability of virtual environments (VEs) that allow users to change and modify their contents and context depending on application requirements has been a de facto feature of virtual reality technology. Engineering uses such as virtual testing and exper- imenting applications demand VEs to be highly or fully reconfigurable. In reality, however, satisfactory reconfiguration of a virtual environment is yet to be achieved, due to the high accuracy of spatial data in- put and…     

虚拟博物馆的三维场景构造及交互漫游实现

虚拟现实技术日趋成熟,针对虚拟场景的构造、交互漫游系统的实现过程展开讨论.系统对徐悲鸿博物馆的主要建筑物、生前作品及其雕塑进行了三维重建,实现了整个博物馆的虚拟漫游.探讨了构建虚拟博物馆三维场景及交互漫游实现过程中的若干关键技术问题,同时为虚拟博物馆系统的建立提供了一种切实可行的途径.     

A Frequency-Domain Approach to Watermarking 3D Shapes

This paper presents a robust watermarking algorithm with informed detection for 3D polygonal meshes. The algorithm is based on our previous algorithm [ 22 ] that employs mesh‐spectral analysis to modify mesh shapes in their transformed domain. This paper presents extensions to our previous algorithm so that (1) much larger meshes can be watermarked within a reasonable time, and that (2) the watermark is robust against connectivity alteration (e.g., mesh simplification), and that (3) the watermark is robust against attacks that combine similarity transformation with such other attacks as cropping, mesh simplification, and smoothing. Experiment showed that our new watermarks are resistant against mesh simplification and remeshing combined with resection, similarity transformation, and other operations..     

三维复杂模型的实时连续多分辨率绘制

本文给出了一种能实时产生由三角网格表示的三维复杂模型的连续多分辨率近似模型并加以绘制的新算法。该算法分为预处理和实时显示两个阶段，在预处理中，对模型上的每个观点按照它们的重要程度进行排序，同时也规定了每个顶点在实时简化过程中的合并操作，实质上也就是确定了模型中的三角形的删除顺序，这使得在实时显示中可以立即得到近似模型。该算法具有两个优点：首先，它建立了视点参数与被选择的分辨率的直接关系；其次，它提     

CAD中三维交互技术的研究与实现

本文研究了ＶＲ技术在ＣＡＤ几何造型中作为交互手段的应用,特别研究了三维交互技术在ＣＡＤ中的实现。通过提出一种用于三维交互的精确视觉线索方法,实现了对三维空间中不同信实体相互位置关系的精确感知。探讨了ＣＡＤ中在三维交互技术支持下的新的几何造型技术。     

Human knowledge acquisition from 3D interaction in virtual environments

Recently,virtual environment (VE) based design and planning,which is a kind of interaction intensive computing,has shown great potential.Most users of such systems are specialists or technicians and their 3D interactions with the system embed a great deal of knowledge and skills.Thus,how to integrate human knowledge and skills into VE is a great challenge to researchers in the human computer interaction field.This paper proposes a method for acquiring user knowledge from VE.The main ideas and work include,abstracting the interactive process and formalizing the interactive semantics,as well as providing a semantic model of an interactive information repository,from which user interactive processes can be retrieved and all kinds of application logics can be established.A virtual assembly planning system is introduced as an example of a practical application of this method.Experiments show that the related models can well capture user knowledge and retrieve the interaction process.     

基于Virtools的三维交互虚拟啤酒灌装线的构建

以虚拟啤酒灌装生产线为研究对象,对大型虚拟设备及灌装生产线的构建过程、模式方法进行了探讨和研究.通过虚拟设计、几何建模及时生产线整体运行时虚拟设备传动关系数学建模,采用Normal Mapping和Shader等次世代图形图像技术,结合Virtools实时渲染引擎,开发出场景式、高交互、超现实、网络化的虚拟啤酒灌装生产线,并将所构建的虚拟生产线应用到职业教育的生产实训和相关企业的岗前培训.     

智能三维虚拟试衣模特仿真系统设计*

针对服装物理仿真通常计算量庞大、在低端硬件平台或交互式环境进行高质量模拟的挑战,将人工生命思想引入服装纹理生成,基于混合虚拟现实技术研究开发了智能三维虚拟试衣模特仿真系统。通过在三维空间中构建与真实人体类似的三维虚拟模特作为消费者的试穿替身,同时设计实现了场景屏风功能,这样不但便于根据着装场合自由切换服装纹理,而且可以让消费者通过这一虚拟平台更为直观、自由地观察着装效果为了使三维试衣系统更为智能化,还建立了服装搭配合适度智能评价系统。     

基于能量评估的网格简化算法及其应用

网格简化是曲面重构和多细节层次构造中的一个重要步骤，本文提出了一个基于局部能量评估的网格简化算法，能够大量地删除密集网格的三角形面片．为了加速算法的执行还提出了一种简单有效的采样方法．算法自动化程度高，能有效地支持多细节层次模型的建立．     

基于3D虚拟现实技术的弹药检测虚拟训练系统设计

目前提出的弹药检测虚拟训练系统接收检测信号接收率较低,检测虚拟训练成功率较低。基于3D虚拟现实技术设计一种新的弹药检测虚拟训练系统,硬件由主控操作机、检测总线接口以及资源测试器组成,软件部分在3D虚拟现实技术下构建虚拟空间,在开放式软件结构构建的基础上进行检测指标划分,对用户界面的文件进行整改,按照弹药检测的指标数据提升整改的方向正确性,选用自检公式对检测的信息进行系统自检,依据检测到的问题的发生形式判断下一次问题发生的触发机制,由此避免下一次问题的产生,从而实现软件流程。实验结果表明,基于3D虚拟现实技术的弹药检测虚拟训练系统能有效提高信号接收率,增强虚拟训练接收成功率,具有较强的应用性。     

Snake terrestrial locomotion synthesis in 3D virtual environments

We present a method for a 3D snake model construction and terrestrial snake locomotion synthesis in 3D virtual environments using image sequences. The snake skeleton is extracted and partitioned into equal segments using a new iterative algorithm for solving the equipartition problem. This method is applied to 3D model construction and at the motion analysis stage. Concerning the snake motion, the snake orientation is controlled by a path planning method. An animation synthesis algorithm, based on a physical motion model and tracking data from image sequences, describes the snake’s velocity and skeleton shape transitions. Moreover, the proposed motion planning algorithm allows a large number of skeleton shapes, providing a general method for aperiodic motion sequences synthesis in any motion graph. Finally, the snake locomotion is adapted to the 3D local ground, while its behavior can be easily controlled by the model parameters yielding the appropriate realistic animations.     

Perceived enablers of 3D virtual environments for virtual team learning and innovation

Virtual teams consist of geographically distributed employees working with a common goal using mostly technology for communication and collaboration. Virtual teams face a number of challenges, discussed in the literature in terms of communication through technology, difficulty in building trust, conveying social cues, and creating awareness, as well as cultural differences. These challenges impact collaboration, but also learning and innovation. This research focuses on how a social medium, the 3D virtual environment, is perceived to enable learning and innovation in virtual teams. We study this through a qualitative study based on interviews of distributed work managers’ perception of VEs. The major findings are that VEs are perceived to create collaborative learning atmospheres for virtual teams in terms of enabling engagement, a shared context awareness, and support in social network building. Another finding is that VEs are perceived to enable team learning, knowledge development, and collaboration through persistence of content, information sharing, learning through role-plays and simulations, and visualization. Furthermore, VEs enable the development of co-created content as well as new ways of working in virtual teams.     

施工管理虚拟环境中的CAD识别和三维重构

给出了识别CAD系统设计结果的数据,并在此基础上介绍了进行三维建模的施工管理虚拟环境,提出了有效的基于OpenGL的三维重构解决方案.在该环境中指定各结构构件间、结构构件同其它数据的相关物理及逻辑属性,动态的模拟施工过程,可以实现施工优化控制和相应的资源可视化管理.     

On multiuser perspectives in passive stereographic virtual environments

The use of stereographic systems is spreading out in modern society, from the revolution of cinematography to its adoption in high‐tech products such as portable gaming devices or photo cameras. However, the fruition of immersive stereographic systems by more than one person at a time is still a research issue. In more detail, the class of passive stereo systems presents technological limitations of displaying correct multiuser perspectives. In fact, the stereo image projected onto the screen is usually rendered according to a unique point of view (PoV). Nevertheless, in multiuser systems, the selection of an appropriate PoV can minimize both optical discomfort and perspective distortion. This paper aims to evaluate which among existing PoV calculation methods provides the best performances in terms of projection realism, optical comfort and overall system usability in multiuser passive stereo systems. The performances have been evaluated in three different “distance” scenarios to take into account also the effects of binocular disparity in the PoV calculation. To accomplish this objective, we administered a questionnaire to nine couple subjects, evaluating each of the investigated PoV calculation methods for each of the three distance scenarios. Copyright © 2013 John Wiley & Sons, Ltd.     

基于Direct3D实现虚拟水泡技术

虚拟现实技术近年来在许多领域得到了广泛应用,介绍了虚拟现实和3D图形技术应用的概况以及Direct3D处理编程的框架结构,通过对自然界水泡理想模型——粒子系统的分析,利用DirectX 9．0软件包进行3D开发,使用VC实现了虚拟现实场景中自然界水泡,为自然界其它自然物体的模拟提供了参考。     

体积保持的多分辨率多边形网格的光顺造型

给出了一个高效的多边形网格的多分辨率光顺造型算法。该算法首先通过引入体积保持约束,快速地实现稠密多边形网格的多分辨率表示,然后结合一个有效的无收缩光顺算法,对网格执行高效的多分辨率光顺编辑,与传统编辑方法不同,该方法利用体积保持约束及优化技术,来自动恢复编辑区域中相应的细节,而无需引入非常损耗资源的局部标架。实验结果表明,该算法计算稳定、高效,能产生复杂的模型。     

几何建模技术在虚拟校园漫游系统开发中的应用

虚拟漫游系统的开发是虚拟现实技术的一个重要应用.以华北电力大学保定二校区为虚拟仿真环境,使用3DSMAX建模工具对校园中的各种模型进行建模,使用多种基于几何建模的场景优化措施,并基于Google Earth卫星截图进行场景的精确布局设计.结合Virtools虚拟现实开发平台,设计了虚拟校园漫游系统的开发流程,并在微机平台上实现了一个场景复杂的校园实时漫游系统.该校园漫游系统不但为用户提供了友好的Web界面,而且设计并实现了基于导航图控制的人机交互机制,便于综合使用多种漫游方式快速漫游校园的场景.     

The design and realization of CoViD: a system for collaborative virtual 3D design

Many important decisions in the design process are made during fairly early on, after designers have presented initial concepts. In many domains, these concepts are already realized as 3D digital models. Then, in a meeting, the stakeholders for the project get together and evaluate these potential solutions. Frequently, the participants in this meeting want to interactively modify the proposed 3D designs to explore the design space better. Today’s systems and tools do not support this, as computer systems typically support only a single user and computer-aided design tools require significant training. This paper presents the design of a new system to facilitate a collaborative 3D design process. First, we discuss a set of guidelines which have been introduced by others and that are relevant to collaborative 3D design systems. Then, we introduce the new system, which consists of two main parts. The first part is an easy-to-use conceptual 3D design tool that can be used productively even by naive users. The tool provides novel interaction techniques that support important properties of conceptual design. The user interface is non-obtrusive, easy-to-learn, and supports rapid creation and modification of 3D models. The second part is a novel infrastructure for collaborative work, which offers an interactive table and several large interactive displays in a semi-immersive setup. It is designed to support multiple users working together. This infrastructure also includes novel pointing devices that work both as a stylus and a remote pointing device. The combination of the (modified) design tool with the collaborative infrastructure forms a new platform for collaborative virtual 3D design. Then, we present an evaluation of the system against the guidelines for collaborative 3D design. Finally, we present results of a preliminary user study, which asked naive users to collaborate in a 3D design task on the new system.