一种改进AABB包围盒的碰撞检测算法

详细分析比较基于包围盒的碰撞检测算法中的轴向包围盒法、方向包围盒法、离散方向多面体法的检测原理和检测效率,并改进了轴向包围盒碰撞检测算法,提出利用简化包围盒边缘节点实现碰撞检测的新设想,其可行性已被初步试验证实。不仅显著提高了碰撞检测的速度,并且可以便捷地得到更为详细的碰撞检测信息,满足了进一步进行碰撞响应处理的需要。使飞行模拟机的视景系统能够实时、准确地检测出虚拟物体间的碰撞。     

布料仿真技术在游戏中的设计和实现

近几年来,布料仿真技术广泛应用于游戏开发中,本文针对游戏在实时性和交互性方面的特殊需求,结合“网络游戏公共技术平台关键技术研究”项目,对布料的物理模型、模型求解以及碰撞检测和处理等方面进行了分析和设计,并在此基础上实现了几种布料动画的模拟。     

Fast and Scalable CPU/GPU Collision Detection for Rigid and Deformable Surfaces

We present a new hybrid CPU/GPU collision detection technique for rigid and deformable objects based on spatial subdivision. Our approach efficiently exploits the massive computational capabilities of modern CPUs and GPUs commonly found in off‐the‐shelf computer systems. The algorithm is specifically tailored to be highly scalable on both the CPU and the GPU sides. We can compute discrete and continuous external and self‐collisions of non‐penetrating rigid and deformable objects consisting of many tens of thousands of triangles in a few milliseconds on a modern PC. Our approach is orders of magnitude faster than earlier CPU‐based approaches and up to twice as fast as the most recent GPU‐based techniques.     

Design and implementation of an FPGA-based parallel graphics renderer for displaying CSG surfaces and volumes

In this paper, the design and implementation of a high-speed “CSG renderer” for displaying convex and concave objects and its performance analysis are presented. The renderer comprises a binary tree-structured depth generator that produces the depth values of a plane at each pixel on the display window simultaneously, and pipelined pixel processors that processes the depth values, a corner bender, and a frame-buffer.In this work, constructive solid geometry (CSG) scene models are used to simplify the hidden area removal and object interference testing. The field programmable gate array technology is used in the implementation.     

Casting shadows with approximated object space accuracy by means of a modified Z-buffer

Shadows are important in enhancing both the realism and the intelligibility of synthetic 2D images of 3D scenes. In order to determine which part of a scene is in shadow, numerous algorithms have been developed. The Z-buffer shadow algorithm and its descendants have proved to be both efficient and easy to implement. However, in casting shadows, the aliasing introduced by the Z-buffer point sampling is notorious. Therefore a new method that is based on a modification of the Z-buffer has been developed. This method deals with the aliasing problem but preserves the strengths of the Z-buffer algorithm. Moreover, as a side effect, the information stored in the modified Z-buffer allows accurate antialiasing of the resulting image.     

Fast collision detection between complex solids using rasterizing graphics hardware

We present an efficient method for detecting collisions between complex solid objects. The method features a stable processing time and low sensitivity to the complexity of contact between objects. The algorithm handles both concave and convex objects; however, the best performance is achieved when at least one object is convex in the proximity of the collision zone (our techniques check the required convexity property as a byproduct of the calculations). The method achieves real-time performance when calculations are supported by the standard functionality of graphics hardware available on high-end workstations.     

工业控制系统抗电磁干扰技术研究

在工业控制系统中，强电与弱电交叉耦合应用环境，干扰错综复杂，严重影响系统稳定性和可靠性。本文介绍电磁兼容性，电源系统干扰以及抑制，总体结构的抗干扰，还介绍几种有效的符合国际标准干扰模拟器，这些模拟器对研究系统抗干扰能力和发现原始设计缺欠十分有效。     

基于物理仿真的布料动画研究综述

随着计算机图形技术的发展,布料动画成为3D游戏和动画电影相关领域研究者共同关心和研究的课题,并呈现蓬勃发展的趋势.布料动画的主要目标是表现布料丰富的运动细节,获得细腻、逼真的动画效果,可广泛应用于游戏、动画和虚拟现实等众多领域.论述了国内外基于物理仿真的布料动画建模的研究现状,总结了基于物理仿真的布料动画基本理论和方法.通过对近年来该领域相关文献的分析和归纳,发现其中存在的优缺点和相互间的联系,力图为3D游戏和动画中布料动画仿真技术的研究提供系统的思路.     

自适应椭球包围盒改进织物碰撞检测方法

为了快速处理织物与模型的碰撞以获得仿真结果,提出一种基于自适应椭球包围盒的碰撞检测方法.该方法以法向距离和径向距离的加权平均值作为表面误差,数值化表示椭球与模型之间的拟合度,将优化K均值聚类方法用于自适应划分模型生成一系列逼近模型的最小体积包围椭球;根据表面误差的大小对椭球分类处理,误差小的椭球直接取代模型区域与织物碰撞,将三角网格之间的碰撞问题转化为质点相对于椭球的穿透测试,误差大的椭球与织物的碰撞检测仅用于排除不可能发生碰撞的三角形,再继续进行三角形之间的精确碰撞检测.实验结果表明,文中方法能快速、自适应地划分任意模型生成高度拟合的椭球,可大幅度地减少碰撞检测计算量,在提高计算速度的同时保证了仿真的真实感.     

结合一种面-面碰撞检测算法的服装动态模拟

实时的服装动态模拟一直是计算机动画的研究热点。在回顾弹性模型及其碰撞问题的相关研究工作的基础上,采用基于质点－弹簧模型的动态模拟方法,产生了虚拟3D模特表面的服装动态效果。其中考虑了织物的非理想弹性属性和变化的空气流作用力,并针对系统实现的瓶颈－服装和人体的碰撞问题,提出一种碰撞检测算法。     

实时毛发建模和动画

提出了基于3D晶格的毛发机械模型和机械变形方法,表现毛发串的体行为,晶格被作为粒子系统采用数学计算变形.毛发机械模型被作为与晶格模型中的各单独头发串片段弹性相关的一系列线性黏弹性晶格弹簧定义.发型足以快速实时表现,同时保留了毛发的特定行为,获得足够的多样性模拟各种复杂发型.用多项式元球模型处理毛发和身体表面之间碰撞.毛发模型具有很高的实时性能和通用性,可达到准确性和计算速度之间的最佳折中.     

INTERFERENCE CHECKING IN COMPUTER-AIDED PLANT DESIGN SYSTEM

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Easy Algorithm Animation on the Web

The animation environment Jeliot automates visualization of algorithms over the Internet. The user can visualize algorithms of his own, not merely the selection supplied by a service provider. Jeliot is based on self-animating data types: the user selects the data objects of the source code to be visualized, and Jeliot produces the animation based on operations performed on those types. We present the design of Jeliot and the principles of its implementation. In addition, we discuss the educational applications of Jeliot.     

A flexible quantitative method for NC machining verification using a space-division based solid model

A geometric-modeling method called Graftree and a system design of an NC (numerical control) machining verifier based on Graftree are proposed. Graftree is constructed by combining Oct-tree and constructive solid geometry (CSG) so as to simulate machining processes precisely in three-dimensional space. Using Graftree, the Boolean operation produces no risk of yielding topological conflicts, which often cause the simulation to stop abnormally. Based on the properties of Graftree, an NC machining verifier is designed to consist of three individual subsystems: data-input operations, geometric simulation, and interactive verification, i.e., visuluatzation of machining scenes and evaluation of the machined product using models of the measuring instruments. This design lets the users watch selectively only the machining steps they want to check precisely, and verify the machining according to dimensional tolerance.     

碰撞检测技术及在桥梁视景仿真中的应用

碰撞检测(Collision Detection)及优化是视景仿真技术中一项非常重要的技术,文中通过对碰撞检测理论的论述,概要介绍了碰撞检测算法关于时间域与空间域的不同分类方法,并讨论如何优化碰撞检测的方法,以减少运算时间与复杂度。通过视景仿真中桥梁碰撞检测的实例对碰撞检测理论及优化算法进行了验证。     

基于角色几何碰撞体估计的实时服装仿真

提出了一种快速处理三维服装仿真中角色与服装碰撞的方法.该方法能够满足交互式实时仿真环境的需求.在预处理阶段,根据蒙皮动画的特点,将角色的几何形状以球和简化凸包等简单碰撞体进行估计.在实时模拟阶段,这些碰撞体跟随骨架运动并代替角色模型网格完成与虚拟服装之间的碰撞处理.此外,为了能够快速计算碰撞响应信息,该方法还利用外围映射机制进一步开发了相交测试的空间局部性.实验结果表明,应用该方法可以有效避免衣片与角色模型之间的相互穿透,同时大幅度地减少碰撞处理计算量.实时仿真系统对于复杂服装网格仍然保持了较高的模拟帧速率.     

A Linear Algorithm for Collision Detection of 3-Dimensional Convex Polytopes

Given two disjoint 3-dimensional convex polytopes P and Q and a straight direction along Which P moves in translation, this paper presents a linear algorithm for determining Whether P collides with Q, and the possible collision positions on P and Q. This result is achieved by using the hierarchicat representation of polytopes, of which the preprocessing time is linear with space.