Deformable mesh for virtual shape sculpting

A novel, interactive virtual sculpting framework based upon a deformable mesh model generated by a self-organizing feature map (SOFM) is described in this paper. The three-dimensional lattice of the SOFM maintains the relative connectivity of neighbouring nodes in the hexahedral mesh as it transforms from the initial reference geometry into the desired shape. Material and dynamic properties are incorporated into the deformable mesh by treating surface and internal nodes as point masses connected by a network of springs. The initial SOFM mesh can be either retrieved from a library of primitive shapes, or created by automatically adapting the 3D mesh to fit selected surface points. Once the initial mesh has been generated, the designer reshapes the virtual object by introducing external forces to the nodal mesh. The process of virtual sculpting is analogous to hand moulding of clay in the physical world where the material mass remains constant. During sculpting, the dynamically changing mesh can be easily rendered in VRML for visualization in a virtual reality environment. The deformable mesh generator and shape-sculpting system are illustrated by reshaping solid meshes created from scanned human heads.     

Deformable models for laparoscopic surgery simulation

This paper introduces a method for handling deformation in interactive, real time computer graphics simulations which involve deformable objects and require a high degree of visual realism. Our proposal, the virtual structure, is a “divide and conquer” approach, which combines a novel physical model with a geometric modelling utilizes the theory of elasticity and Newtonian mechanics, applied by a numerical method, the finite element method. Using different levels of structural resolution for global and local or collision with other objects. The geometric modelling uses the physical structure as a set of control points and produces a fine polygonal mesh generated by a B-spline surface. In order to demonstrate the method we have modelled the gallbladder as a spherical membrane containing liquid, in an interactive simulated environment for laporoscopic cholecystectomy.     

Real-time simulation for a virtual reality-based MIG welding training system

This paper describes a real-time welding simulation method for use in a desktop virtual reality simulated Metal Inert Gas welding training system. The simulation defines the shape of the weld bead, the depth of penetration, and the temperature distribution in the workpiece, based on inputs from the motion-tracking system that tracks the position of the welding gun as a function of time. A finite difference method is used to calculate the temperature distribution, including the width of the weld bead and the depth of penetration. The shape of the weld bead is then calculated at each time step by assuming a semi-spherical volume, based on the width of the weld bead, the welding speed, and the wire feed rate. The real-time performance of the system is examined, and results from the real-time simulation are compared to physical tests and are found to have very good correlation for welding speeds up to 1,000 mm/min.     

虚拟情景实训环境三维模拟

应用计算机技术当中的虚拟模拟技术,对于当前各领域实现虚拟情景三维模拟训练已成为可能。本文研究当前技术环境下,利用Unity3D模拟平台构造虚拟情景训练系统的开发与设计。从三维模拟训练系统的关键技术研究入手,以三维场景优化、物理碰撞逻辑检测、动态加载场景以及网络通信作为开发的重点,设计出较为先进和逼真的虚拟情境下三维模拟训练系统。并以消防部门作为系统应用的检测部门,检测结果表示此系统可以很好的表现出现场场景的模拟程度以及逻辑,对于加强消防部门的训练技术和应用效果有很大优势。     

Landmine detection training simulation using virtual reality technology

Virtual Reality - Landmines are frequently used for defence and attack. Thus, landmine detection is vital to preventing the damages incurred. Various landmine detection methods have been developed...     

装备分布式虚拟维修训练云仿真关键技术

传统分布式虚拟维修训练系统仿真任务和仿真设备耦合度高,系统仿真效率低,扩展困难;同时,作为分布式交互支撑的高层体系结构(HLA)和运行支撑框架(RTI)仅适用于局域网络,无法实现大范围的仿真资源共享和维修协同互操作。借鉴云计算和云仿真思想,提出了一种应用于装备虚拟维修训练领域的云仿真体系结构和框架实现方案;研究了面向Web服务的广域网RTI组件层次化体系结构,设计了基于Web服务的仿真邦员,实现了仿真过程监控和远程邦员任务迁移功能;基于最小调度法实现了仿真平台的动态负载平衡,研究了平台的可视化仿真功能和仿真数据的分布式存储技术。在此基础上完成了某型装备的虚拟维修训练网络化仿真开发,初步证明了虚拟维修训练云仿真的可行性和有效性     

装备虚拟维修训练系统工程研究

以虚拟现实技术为基础，提出了装备虚拟维修训练系统建设总体方案，并完成了第一期的建设任务。该系统的实现，对于解决目前存在的复杂装备维修训练问题有重要意义。     

Networking for distributed virtual simulation

Distributed Virtual Simulation (DVS) is a new technology that extends Virtual Reality to the networked environment. It was developed for military training and is being used for civilian education and entertainment. Participants can interact over great distances in the virtual world if supported by a network that provides real-time, multicast packet communications with resource reservation for adequate performance, and satisfactory security. Requirements and techniques for real-time networking, internetted multicast, and resource reservations in support of DVS are described, and are used to define the set of missing Internet technologies that will be needed for DVS.     

虚拟喷泉的计算机生成技术

介绍粒子系统和水波的物理学特性,研究生成模拟喷泉、水波、浪花及泡沫的理论基础．用粒子系统模拟喷泉、浪花及泡沫．实验证明该方法在生成速度和图像上都能获得非常好的效果．     

可变形网格引导的群体队形仿真

目的 许多群体运动仿真算法侧重于模拟由大量自由移动个体所组成的群体行为,而针对具有特定队形的群体运动仿真算法较少。为解决这一问题,采用改进的网格引导方法,利用可变形网格对群体运动进行控制。方法 首先,对群体队形进行三角划分,建立一个连接所有智能体的队形网格。然后,利用障碍势场法在群体运动的过程中对队形网格进行变形,使智能体在避免与障碍物发生穿透的同时尽可能保持整体队形稳定。最后,针对障碍物穿过队形网格时可能造成的局部智能体 “错位现象”,提出了基于吸引点的网格引导方法,使群体绕过障碍物后能迅速恢复原来队形。结果 使用Unity软件对军队行进、动态车流、群体表演等场景中的智能体编队移动进行仿真,并设置了不同规模的群组交换实验进行对比。本文算法的实时计算花销主要集中在网格变形阶段：在队形网格顶点总数为1 000时,单位仿真步内网格变形阶段的平均运行时间为20.15 ms。队形网格划分阶段是一个预先进行的过程,不影响算法实时性。基于吸引点的网格引导方法提高了智能体的全局移动效率,使队形变化更加自然流畅。结论 实验结果表明,可变形网格引导的群体队形仿真算法在群体运动过程中能有效维持队形稳定,无论障碍环境是静态的还是动态的都能实现良好的群体避障,说明算法的有效性。     

正颌截骨术中的凸柱体网格切割算法研究

计算机辅助虚拟手术技术对正颌外科手术方案的制定、手术效果的预测分析发挥着重要作用。然而,现有的计算机辅助正颌截骨术只能实现少量简单的截骨操作,不能满足虚拟截骨术多样性的需要。在平面切割地基础上,提出了一种基于凸柱体网格切割算法。该算法用凸柱体模拟虚拟手术刀对三维网格模型进行切割,根据截骨术的切口类型构造柱体,用此柱体进行切割实现骨块的分离。实验结果表明,该算法能有效地实现多种复杂虚拟截骨术,为手术方案的制订提供了辅助指导作用。     

"虚拟仿真综合实训"课程融入思政内容设计

采用纵向和横向两条线进行"虚拟仿真综合实训"课程思政内容设计.纵向即按照实训的不同阶段来安排思政内容,横向即按照实训的不同主体单位来安排思政内容.对"虚拟仿真综合实训"课程思政教育教学体系的探索,必将使学生在学习专业技能的同时不断提高自身思想政治水平,真正成为德才兼备的新时代人才.     

面向机务虚拟维修训练的虚拟手操作设计

机务维修训练强调手部操作要素,针对虚拟维修过程中手部操作较简单且控制复杂的问题,提出一种基于基本维修作业分类的虚拟手操作仿真方法。基于层次化分解思想构建出新的分解策略,将机务维修任务分解为任务层、子任务层和基本维修作业层,并设计规则实现基本维修作业到虚拟手操作的映射,通过在3ds MAX中构建虚拟手仿真模型,利用骨骼动画技术实现虚拟手的控制,减轻虚拟手关节运动的控制负担,在自主开发的机务训练装备上进行虚拟手操作实验,以飞机电子舱门操作为例,验证方法的可行性和实用性。     

A novel virtual reality simulation training system with haptic feedback for improving lateral ventricle puncture skill

Virtual Reality - The lateral ventricle puncture is an important step of external ventricular drain. It is one of the most basic but challenging skills that must be mastered by physicians. For...     

虚拟培训中的虚实联动技术

针对传统培训方式的不足,提出了虚实联动的培训方式.通过构建虚拟设备,硬件可编程逻辑控制器(PLC)、PC、虚拟设备三者之间的通信,实现虚拟设备和实体设备之间的联系,并且通过现场控制系统采集实体设备运行数据,将实体设备运行和故障等信息在虚拟设备中实时表现出来,拓展了虚拟培训的新思路.以喷印机虚拟联动系统为例论述了虚拟联动技术的必要性和可行性.     

Human-systems interaction for virtual environment team training

Virtual environments are increasingly used to support collaborative activities and distance learning. However, few are designed to support students, instructors and simulations in multi-participant team training. This paper describes the Training Studio, a system for authoring, delivering and evaluating multi-participant team training in an immersed virtual environment. The Training Studio focuses on human-systems interaction, allowing multiple students to learn and perform team tasks. The Training Studio supports collaborative learning for either single or multi-participant activity. This is accomplished through the use of agents which are assigned to students to act as personal mentors or missing team members. Conducting team training within a virtual environment introduces complexities and issues unique to team training and multiple-participant virtual environments. This paper describes our approach to virtual environment team training, discussing issues confronted and resulting design considerations and implementations.