虚拟人物实时毛发动画

提出了一个基于晶格的机械变形方法。晶格被作为一个粒子系统采用数学方法变形,毛发采用2次B样条插值方法绘制。用元球模型处理毛发和身体表面之间碰撞。发型机械模型具有很高的实时性能和通用性,可以用来模拟各种复杂发型。模型可达到各种绘制背景下准确性和计算速度之间的最佳折中。     

Adaptive Nonlinear Finite Elements for Deformable Body Simulation Using Dynamic Progressive Meshes

Realistic behavior of deformable objects is essential for many applications such as simulation for surgical training. Existing techniques of deformable modeling for real time simulation have either used approximate methods that are not physically accurate or linear methods that do not produce reasonable global behavior. Nonlinear finite element methods (FEM) are globally accurate, but conventional FEM is not real time. In this paper, we apply nonlinear FEM using mass lumping to produce a diagonal mass matrix that allows real time computation. Adaptive meshing is necessary to provide sufficient detail where required while minimizing unnecessary computation. We propose a scheme for mesh adaptation based on an extension of the progressive mesh concept, which we call dynamic progressive meshes.     

Mesh Optimization for Polygonized Isosurfaces

In this paper, we propose a method for improvement of isosurface polygonizations. Given an initial polygonization of an isosurface, we introduce a mesh evolution process initialized by the polygonization. The evolving mesh converges quickly to its limit mesh which provides with a high quality approximation of the isosurface even if the isosurface has sharp features, boundary, complex topology. To analyze how close the evolving mesh approaches its destined isosurface, we introduce error estimators measuring the deviations of the mesh vertices from the isosurface and mesh normals from the isosurface normals. A new technique for mesh editing with isosurfaces is also proposed. In particular, it can be used for creating carving effects.     

A High Performance Solver for the Animation of Deformable Objects using Advanced Numerical Methods

Physically based modelling of deformable objects has become the most popular technique to model textiles, skin or human tissue. The crucial problem in the animation of deformable objects is the solution of the resulting differential equations. Recently fast solutions have been presented. In this work we will first give a theoretical analysis and then exploit special properties of the system and advanced numerical techniques to achieve further speed-ups of the simulations. Also, higher accuracy, leading to higher quality animations, will be achieved and an error bound is enforced.     

Modeling Dynamic Hair as a Continuum

In this paper we address the difficult problem of hair dynamics, particularly hair-hair and hair-air interactions. To model these interactions, we propose to consider hair volume as a continuum. Subsequently, we treat the interaction dynamics to be fluid dynamics. This proves to be a strong as well as viable approach for an otherwise very complex phenomenon. However, we retain the individual character of hair, which is vital to visually realistic rendering of hair animation. For that, we develop an elaborate model for stiffness and inertial dynamics of individual hair strand. Being a reduced coordinate formulation, the stiffness dynamics is numerically stable and fast. We then unify the continuum interaction dynamics and the individual hair's stiffness dynamics.     

Integrating Behavioural Animation Techniques

Our research focuses on animating autonomous virtual humans which are able to take decisions by themselves. We especially address in this paper the technical problem of integrating altogether the physical simulation of agents (represented as virtual humans in a 3D environment) and their behaviours and motivations, driven by a Beliefs, Desires and Intentions architecture. We also explain how goals drive plans, and how an agent can coherently handle concurrent tasks.     

Generalized Stochastic Sampling Method for Visualization and Investigation of Implicit Surfaces

Recently we proposed the stochastic sampling method (SSM), which can numerically generate sample points on complicated implicit surfaces quickly and uniformly. In this paper we generalize the method in two aspects: (1) We introduce two kinds of boundary conditions, so that we can sample a finite part of an open surface spreading infinitely. (2) We generalize the stochastic differential equation used in the SSM, so that its solutions can satisfy plural constraint conditions simultaneously. The first generalization enables us to visualize cut views of open surfaces. The second generalization enables us to visualize intersections of static and moving implicit surfaces, which leads to detailed investigation of intersections and other interesting applications such as visualization of contour maps.     

基于Maya的人物角色行走运动的设计

阐述在Maya软件中制作人物角色行走的流程以及一些相关注意事项。通过分析人体行走过程的重要特征,详细论述人物角色行走动画的制作过程,探讨Maya技术在人物角色行走动画中的应用技巧。     

蒙皮约束下的动画角色模型分割方法

动画角色的数据重用可以提高游戏与动画的制作效率并丰富角色类型.针对模型数据重用的首要步骤——动画角色的三维网格分割问题,提出了一种蒙皮约束下的分割方法,利用蒙皮信息的运动相关性,产生依据该信息的部件预分割,在预分割结果上进行拓扑检查并调整,进而再对切口处进行优化处理,最终产生适合动画角色融合的网格部件.最后给出在用游戏公司提供的真实数据上对新方法进行的了测试,结果,证明了表明该新方法的简洁有效并说明了其适用范围.     

面向虚拟维修训练的自抓取虚拟手交互行为构建

针对当前维护训练模拟器（MTD）不能很好地向受训者展示飞机维修过程中的具体维修动作的问题,构建一种自抓取的虚拟手与相应的交互行为,以提高机务培训质量。通过分析维修的基本动作要素,定义与构建基于蒙皮骨骼的虚拟手动作库;在场景漫游阶段,实时获取视角位置来驱动虚拟手运动,减轻场景漫游下的虚拟手控制负荷;在具体维修操作阶段,利用所提的交互行为算法,将虚拟手的位置自调节与骨骼动画osgCal相结合,通过调取动作库中的相应动作,完成具体的维修任务。实验结果表明,所提出的方法能较好地展现具体的维修操作,对于虚拟维修训练具有良好可用性。     

基于语义虚拟环境的虚拟人动画研究与实现*

现有虚拟环境建模（如VRML/X3D）主要集中在几何图形的描述,所显示的虚拟场景对于人是可理解的,但对于计算机是不可理解的,因而难以作有意义的自动处理。基于语义Web设计了一个语义虚拟环境（主要包括语义虚拟场景和语义虚拟人）,并设计了基于语义虚拟环境的虚拟人动画引擎。语义虚拟环境使得计算机能够理解和自动处理虚拟环境的语义信息,并且使得虚拟环境系统具有可重用性、可扩展性和可集成性。最后,在语义虚拟环境和虚拟人动画引擎的基础上开发了一个办公室场景中智能虚拟人行动推理的系统,取得了很好的效果。     

基于分运动叠加的个性化虚拟人步行姿态研究

依据运动叠加的思想,将人体步行运动分解为10个分运动,并建立了一个能充分表现这些分运动的虚拟人几何模型。通过一个简单的动作捕获实验,获取人体步行运动的运动数据。分析每个分运动的规律,给出各个分运动的近似的运动方程。通过对分运动的研究,寻找出能够反映步态多样化的参数。用自行开发的演示软件,再现由分运动合成的步行运动。通过调节步行姿态特征参数,可获得能反映不同类型人物个性的步行动画。     

基于计算机动画的虚拟导游技术及其应用

基于虚拟现实技术的虚拟旅游正蓬勃发展,正如导游在旅游业的重要地位一样,虚拟导游也是虚拟旅游技术的重要组成部分。该文利用计算机人物建模和动画技术,实现了基于计算机动画的虚拟导游,有效地增强了虚拟旅游场景的趣味性和真实感。讨论了基于计算机动画的虚拟导游的关键技术,并将其应用于虚拟旅游系统,效果良好。     

纹理合成技术综述

纹理合成是当前计算机动画、特效和虚拟现实领域的研究热点之一,在过去的几年里,纹理合成技术取得了长足的发展。本文把近几年纹理合成技术的算法特点进行深入分析论述,对纹理合成的发展进行展望。     

基于运动捕获数据的虚拟人动画研究

随着三维游戏等行业对计算机动画制作需求的增加,在三维动画制作软件中人工调整虚拟人动作的工作方式已经不再适合现在的计算机动画制作。运动捕获技术是直接记录物体的运动数据并将其用于生成计算机动画,具有高效率、所生成的动画真实感强等优点,因而获得了广泛应用。提出了一种利用运动捕获数据来生成动画的方法,基于运动捕获得到的数据建立并驱动三维骨架模型,从而产生骨架的运动,形成动画。该方法可以充分利用现有的大量运动捕获数据,因此具有较大的应用前景。