虚拟现实技术与建筑设计

计算机技术飞速发展,正在改变传统的建筑设计方法,其中虚拟现实技术为建筑学和CAAD领域提出了一个新的概念——“虚拟建筑”。虚拟现实技术是一种新型的信息技术,集成了计算机图形学、多媒体、人工智能、多传感器、网络、并行处理等技术的最新发展成果。本文通过分析虚拟现实技术的特征,探讨这一技术将来对建筑设计领域产生的影响,总结出一些新的CAAD概念和方法。

基于RCS的虚拟现实系统中飞行航迹的测量

讨论RCS在虚拟现实系统中测量飞行航迹的应用。建立全面的RCS数据库,利用姿态角提取飞机RCS值,然后在数据库中提取航迹,该方法有效地提高了模拟测量效率。

互联网虚拟信用套现的法律分析——基于花呗套现判决的研究

互联网虚拟信用套现的脱法行为愈演愈烈,危及了正常的金融秩序。花呗套现作为虚拟信用套现的典例,涉及诸多法律领域,而且广泛发生于全国许多省市,因此有必要对其进行法律分析。从民事与刑事的分野的视角,研究平台自律的"软法"调制、民事法律规制、刑事责任细化,是花呗套现这一脱法行为进行法理分析的有效路径。面对互联网虚拟信用套现等金融创新行为,建议明确监管主体的职责,加强各机构、各领域的协调制度建设;同时恪守法律谦抑性,明确规则适用的序位选择,拒绝过度的立法供给,保证法律的实效性。

Design of research platform on telerobot system based on virtual reality technology

A design strategy for a research platform of a telepresence telerobot system based on virtual reality technology is put forward. The design frame of the system is described, and its important core techniques are described. An octrees data structure is utilized to build kinematic and dynamic modeling of the virtual simulation environment, Delphi+OpenGL+3DS MAX are adopted to carry through the virtual modeling and visible simulation exploitation of the slave-robot and its environment. Photo-correction is adopted to correct positioning deviation of the virtual geometric model and modeling errors. The cost of software and hardware equipment for the research platform realized is low. The master/slave robot (manipulator) system and all software in the system were designed and manufactured by our research group. The performance of the system has reached the level required for research. An indispensable experiment base is provided for the research of a telepresence telerobot system based on virtual reality technology.

AN ALGORITHM OF DISTANCE CALCULATION BETWEEN A BOUNDING SPHERE AND A BOUNDING CSG PRIMITIVE

A simple method for calculating distance between a solid sphere and a constructive solid geometry (CSG) so lid primitive (including block, cone, cylinder, sphere, wedge and torus) is derived to support the collision detection algorithm. By decomposing the whole space into relative positions and geometric features of the sphere and the primitive considered, closed form distance formula are got. These calculations are very useful in the real time collision detection in which primitives are used as bounding volumes of complex objects.

A robot simulation system with virtual force display and feedback based on master manipulator

This paper describes a virtual environment, which can present dynamic force transformation during the control of objects. A 5-DOF haptic interface with the capability to generate kinesthetic effect is combined. In this system, the operator manipulates an object in a virtual environment by using the 5-DOF master arm. When contacting with the virtual object, the contact force can be calculated and shown in the graphic interface. The contact response and deformation of the virtual object, which are usually called haptic rendering, also can be performed. The study supplies an approach to improve the operator’s immersion and can be used in many tele-robot control fields.

Application and Implementation of Quest3D Technology in Garden Landscape Design

The application of virtual reality technology has become more and more influential in garden design. Quest3D as a significant software to realize the virtual reality technology is utilized in this study to make a garden roaming demonstration system with the gardening design of a classical courtyard as an example. Besides, the advantages and disadvantages of applying Quest3D technology in garden landscape design are elaborated from the perspective of the selection of Quest3D technology, basic procedures for the selection and establishment of software and hardware.

VIRTUAL REALITY BASED THREE-DIMENSIONAL GUIDE WIRE PROPAGATION SIMULATION FOR ENDOVASCULAR INTERVENTION

The virtual reality based motion simulation of the guide wire and the catheter inside specific vascular structures can benefit a lot for the endovascular intervention. A fast and well-performed collision cancellation algorithm is proposed based on the geometric analysis and the angular propagation （AP）, and a 3-D real-time interactive system is developed for the motion simulation of the guide wire and the catheter inside the specific patient vascular. The guide wire or the catheter is modeled as the ＂multi-body＂ representation and properties are defined by its intrinsic characteristics. The motion of the guide wire or the catheter inside the vascular is guided by the collision detection and the collision cancellation algorithm. Finally, a relaxation procedure is used to achieve more realistic status. Experimental results show that the behavior of the guide wire or the catheter depends on the defined parameters. The real-time simulation can be achieved. The result shows that the simulation system is effective and promising.

基于真实实验视频和数据的“虚拟真现”物理实验~——以伏安法测电阻实验为例

提出一种新的虚拟实验方法——虚拟真现实验,即采用虚拟的界面调节实验参数,调用并呈现真实的实验现象和实验数据。以伏安法测电阻为例介绍“虚拟真现”实验的设计与实现,首先完成真实物理实验现象视频和实验数据的采集、存储和索引,然后设计虚拟人机界面,实验者在虚拟界面调节实验设备参数（即实验自变量）时,软件根据自变量值检索数据记录文件中对应的真实物理现象视频和实验响应数据,最终呈现与真实实验相符的实验现象和实验数据。虚拟真现实验具有更好的拟真度,有利于学生操作能力、数据处理能力的培养。

Calibration Scheme Under Spherical Coordinates for Magnetic Tracker Used in VR System

A calibration scheme under spherical coordinates is described for a magnetic tracker used in VR (virtual reality) system. A look up table containing data of tracked values for certain positions in the working space, spe cified in spherical coordinates, is generated first, which is then used to calibrate the tracking results by a two dimensional interpolation. The scheme can effectively correct the static errors in the magnetic tracking system. The employment of spherical coordinates significantly reduces the calculation complexity in calibration.

Radial Based Probabilistic Roadmap Motion Planning Method in Sparse Environment

A new dynamic path planning method in high dimensional workspace, radial based probabilistic roadmap motion (RBPRM) planning method, is presented. Different from general probabilistic roadmap motion planning methods, it uses straight lines as long as possible to construct a path graph, so the final path obtained from the graph is relatively shorter and straighter. Experimental results show the efficiency of the algorithm in finding shorter paths in sparse environment.

Research on the Dynamic Simulation System of Maize Growth

Dynamic simulation system of maize growth is developed by the physiological and ecological model,morphological structure model,computer science and virtual reality technology,to improve the level of precise operation of maize production.The computer graphics algorithms,virtual reality technology,animation design and information integration technology are applied to maize production by this system.establishment of dynamic simulation system of maize growth is conducive to raise level of precise operation in maize production.The system also can assist the relevant production research and testing,to reduce cost and improve efficiency.

On 3D Geo-visualization of a Mine Surface Plant and Mine Roadway

Constructing the 3D virtual scene of a coal mine is the objective requirement for modernizing and processing information on coal mining production. It is also the key technology to establish a ＂digital mine＂. By exploring current worldwide research, software and hardware tools and application demands, combined with the case study site （the Dazhuang mine of Pingdingshan coal group）, an approach for 3D geo-visualization of a mine surface plant and mine roadway is deeply discussed. In this study, the rapid modeling method for a large range virtual scene based on Arc/Info and SiteBuilder3D is studied, and automatic generation of a 3D scene from a 2D scene is realized. Such an automatic method which can convert mine roadway systems from 2D to 3D is realized for the Dazhuang mine. Some relevant application questions are studied, including attribute query, coordinate query, distance measure, collision detection and the dynamic interaction between 2D and 3D virtual scenes in the virtual scene of a mine surface plant and mine roadway. A prototype system is designed and developed.

Visual fatigue relief zone in an extra-long tunnel using virtual reality with wearable EEG-based devices

Long-time driving and monotonous visual environment increase the safety risk of driving in an extra-long tunnel. Driving fatigue can be effectively relieved by setting the visual fatigue relief zone in the tunnel. However, the setting form of visual fatigue relief zone, such as its length and location, is difficult to be designed and quantified. By integrating virtual reality(VR) apparatus with wearable electroencephalogram(EEG)-based devices, a hybrid method was proposed in this study to assist analyzers to formulate the layout of visual fatigue relief zone in the extra-long tunnel.The virtual environment of this study was based on an 11.5 km extra-long tunnel located in Yunnan Province in China.The results indicated that the use of natural landscape decoration inside the tunnel could improve driving fatigue with the growth rate of attention of the driver increased by more than 20%. The accumulation of driving fatigue had a negative effect on the fatigue relief. The results demonstrated that the optimal location of the fatigue relief zone was at the place where driving fatigue had just occurred rather than at the place where a certain amount of driving fatigue had accumulated.

Study of virtual reality for mild cognitive impairment:A bibliometric analysis using CiteSpace

Objectives Non-invasive and low-cost virtual reality(VR)technology is important for early evaluation and intervention in mild cognitive impairment(MCI).This study aimed to demonstrate the current status of overseas and domestic research as well as the focus and frontier of VR technology among individuals with MCI through a bibliometric analysis.Methods Studies from the core collection of Web of Science™between 1995 and 2020 were used;furthermore,CiteSpace 5.7 R3 was utilized to analyse information on authors/cited authors,keywords,burst words,and cited references.Results In total,230 publications were identified.Most studies were published in the USA(45 publications)and Italy(41 publications),where Guiseppe Riva ranks first(14 publications),and Tarnanas I is the author with the highest centrality(0.44).The hot topics in VR applications in the MCI population are‘physical activity,’‘people,’‘single-blind,’‘disease,’‘walking,’‘technology,’‘working memory,’and‘risk’in recent years.The keyword‘mild cognitive impairment’has attracted extensive attention since 2012,showing the strongest citation outbreak(8.28).The clustering results of the literature show the research types and emerging trends,including‘exergame,’‘serious games,’‘spatial navigation,’‘activities of daily living,’‘exercise,’‘enriched environment’and‘wayfinding.‘Conclusions Cognitive assessment and nonpharmacological intervention research on patients with MCI have become the focus of dementia prevention in recent years.Virtual technology,combined with traditional methods such as exercise therapy,provides new ideas for innovative cognitive evaluation and cognitive intervention.

Design and Implementation of a 3D Ocean Virtual Reality and Visualization Engine

In this study,a 3D virtual reality and visualization engine for rendering the ocean,named VV-Ocean,is designed for marine applications.The design goals of VV-Ocean aim at high fidelity simulation of ocean environment,visualization of massive and multidimensional marine data,and imitation of marine lives.VV-Ocean is composed of five modules,i.e.memory management module,resources management module,scene management module,rendering process management module and interaction management module.There are three core functions in VV-Ocean:reconstructing vivid virtual ocean scenes,visualizing real data dynamically in real time,imitating and simulating marine lives intuitively.Based on VV-Ocean,we establish a sea-land integration platform which can reproduce drifting and diffusion processes of oil spilling from sea bottom to surface.Environment factors such as ocean current and wind field have been considered in this simulation.On this platform oil spilling process can be abstracted as movements of abundant oil particles.The result shows that oil particles blend with water well and the platform meets the requirement for real-time and interactive rendering.VV-Ocean can be widely used in ocean applications such as demonstrating marine operations,facilitating maritime communications,developing ocean games,reducing marine hazards,forecasting the weather over oceans,serving marine tourism,and so on.Finally,further technological improvements of VV-Ocean are discussed.

CAD-VR geometry and meta data synchronization for design review applications

In this paper we present the MEMPHIS middleware framework for the integration of CAD geometries and assemblies with derived Virtual Reality (VR) models and its specific meta data and attributes. The goal of this work is to connect real time VR applications, especially for the Design Review, with enterprise software storing and managing CAD models (Product Data Man- agement—PDM). The preparation of VR models requires expert knowledge, is time consuming, and includes selection of required CAD data, tessellation, healing of unwanted gaps, applying materials and textures, and special surface and light effects. During the Design Review process, decisions are made concerning the choice of materials and surface forms. While materials can be switched directly on the VR model, the modification of part geometries must be made on the CAD model. Our system synchronizes modi- fications of the original CAD geometries and of attributes that are relevant for the realistic rendering using the PLM Services standard. Thus, repeated work for the VR preparation can be avoided.

Virtual Reality Based Process Integrated Simulation Platform in Refinery:Virtual Refinery and Its Application

With the combination between system simulation and virtual reality,we have established an integrated virtual refinery simulation platform,and analyzed the overall design and principal architecture.This paper introduces a simulation algorithm about a refinery based on virtual reality,and explains how the algorithm can be applied to the virtual refinery integrated simulation platform in detail.The virtual refinery simulation platform,which consists of a three-dimensional scene system,an integrated database system and a dynamic-static simulation system,has many applications,such as dynamic-static simulation of key process unit used as process control and oil tank blending simulation for scheduling.With the visualization and human-computer interaction for acquiring production and process data,this platform can provide effective supports on staff training related with monitoring,control and operation in refinery.Virtual refinery can also be web published through the internet and it is helpful for the distance training and education.

The Application of Virtual Reality Technology to Ear Microsurgery

The broad application of virtual reality (VR) to medicine has been of great value. The virtual surgery is one of technically difficult applications. With the expansion of the increasingly fine and complicated ear microsurgery, new methods are required to train the doctors. It is necessary and of practical significance to apply VR to the ear micro-operation, which is a functional operation with high precision and great difficulties. In this article, medical VR applications were reviewed. The application of VR to the ear microsurgery was discussed and the virtual ear microsurgery system was designed.

Virtual Reality Simulation of Fuzzy-logic Control during Underwater Dynamic Positioning

In this paper, graphical-user-interface （GUI） software for simulation and fuzzy-logic control of a remotely operated vehicle （ROV） using MATLABTM GUI Designing Environment is proposed. The proposed ROV＇s GUI platform allows the controller such as fuzzy-logic control systems design to be compared with other controllers such as proportional-integral-derivative （PID） and sliding-mode controller （SMC） systematically and interactively. External disturbance such as sea current can he added to improve the modelling in actual underwater environment. The simulated results showed the position responses of the fuzzy-logic control exhibit reasonable performance under the sea current disturbance.