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1.
用随机正弦波拟合卡通流水   总被引:17,自引:2,他引:15  
在过去20年中人们提出许多处理水运动的方法,但大都致力于生成真实感的动画,而对传统手工绘制的水运动效果建模问题几乎无人涉及,给出一个等级结构的卡能流水模型,首先分析了卡通汉水的绘制过程,从中提取卡通流水的静态要素与动态要素,然后以正弦波为基础对其幅度、频率以及相位进行随机扰动定义水波形状,并在指定边线范围内控制它们的运动来生成卡通流水,此外还给出了生成三维卡通流水的方法以及相应的动画图例。  相似文献
2.
一个用于立体卡通动画的流水模型   总被引:9,自引:2,他引:7       下载免费PDF全文
提出了一个用于立体卡通动画的流水模型.介绍了如何把手工绘制的卡通流水画面分解成不同的部分,从中提取流水序列的静态信息与动态信息.基于这些信息,建立了一个具有等级结构的模型.通过调整少量的控制参数,模型可以自动生成与手工绘制卡通流水风格一致的动画序列.一个重要的工作是把卡通流水模型扩展到三维,并在CAVE立体投影系统中生成立体卡通流水动画.  相似文献
3.
Computer graphics for water modeling and rendering: a survey   总被引:5,自引:0,他引:5  
A key topic in computer graphics is the realistic representation of natural phenomena. Among the natural objects, one of the most interesting (and most difficult to deal with) is water. Its inherent complexity, far beyond that of most artificial objects, represents an irresistible challenge for the computer graphics world. Thus, during the last two decades we have witnessed an increasing number of papers addressing this problem from several points of view. However, the computer graphics community still lacks a survey classifying the vast literature on this topic, which is certainly unorganized and dispersed and hence, difficult to follow. This paper aims to fill this gap by offering a historical survey on the most relevant computer graphics techniques developed during the 1980s and 1990s for realistic modeling, rendering and animation of water.  相似文献
4.
河流水质模型的逼近方法及误差分析   总被引:2,自引:0,他引:2  
史忠科 《控制与决策》2002,17(Z1):668-671
提出一种平稳河流水质模型简化方法.通过分析存在弥散和忽略弥散作用两种情况下的Streeter-Phelps模型的解,给出了忽略弥散作用的条件和最大误差分析,进而给出多河段模型的一般表达式.数值计算和实际验证结果表明,该方法可给出工程满意的结果.  相似文献
5.
3维卡通水与物体交互作用的动画建模   总被引:2,自引:0,他引:2  
为了生成水与物体交互作用的卡通动画,提出一个混合式的3维卡通水模型。先构造出复杂的各种卡通水波模型,然后在2维工作区上对它们进行结构上的组合并映射到3维水面上进行绘制;障碍物在3维水面上的覆盖区域被检测出来之后,将其逆映射到2维工作区并在工作区内实现流水波形和障碍物所在区域的碰撞检测,根据碰撞检测结果触发障碍物附近的激起浪花波形。该方法的特点在于既表现了卡通流水与障碍物的碰撞,又保持了手工绘画的艺术感。此外,用户还可以方便地对波形的形态、位置、速度等进行设置与调控。系统利用GPU(图形处理器)硬件处理能力实现了对3维卡通水与物体交互的实时绘制。  相似文献
6.
The main interest of the present study is the simulation of wind-induced currents in closed water bodies with shallow and deep regions. This paper describes a low time consumption numerical modelling technique for the simulation of free-surface flow over a geometrically complex bed. To achieve this, a technique employing coupled two- and three-dimensional flow solvers is developed for simulation of the flow. The conjunctive model consists of an upper part 2D Shallow Water Flow Solver (2D-SWFS) coupled with a 3D pseudo-compressible flow solver (3D-PCFS) for the deep regions with a proper interface boundary condition. The 2D-SWFS and 3D-PCFS solvers are coupled via an interfacial shear stress gradient and pressure effects. Time stepping is performed for the 2D solver, and an iterative procedure is employed by the 3D solver to satisfy the equilibrium constraints for the interfacial boundary. The model is able to consider 2D wetting and drying shallow regions without any underlying deep water. Both the 2D and 3D models use nodal based Galerkin finite volume method (GFVM) for solving the governing equations on the unstructured meshes. The accuracy of both models in solving the effective phenomena is examined by comparing the results of simulated test cases with readily available analytical solutions and experimental measurements. Finally, the accuracy of the conjunctive model is assessed by comparing its results for test cases with analytical solutions and experimental measurements from the literature. The new simulation method is then used to solve a wind-induced flow problem in a basin with deep water surrounded by shallow water parts.  相似文献
7.
In this paper, we present sufficient smoothness results on the solution of a nonlinear shallow water problem in order to obtain an existence result for the associated adjoint problem. We introduce a necessary but not sufficient existence condition for the functional minimum. The control is made on the velocity boundary condition, in considering observations at isolated points. Moreover, we give a set of numerical results obtained in a real situation.  相似文献
8.
提出一个生成中国画风格水动画的方法.首先检测手工绘制国画水波的位置,然后利用自回归模型合成这些水波形状.合成的水波用基于图像方法来绘制以使水波与手工绘制国画风格一致.最后,将水波放在手工绘制的国画环境中运动起来构成动画.所附图例展示该方法能够获取手工绘制水波样本的统计特性而生成富有变化的非真实感水动画序列.  相似文献
9.
During the continuous casting of steel, several disturbances occur and affect all the parts of the caster, including the mould where the molten steel has to be stable for good quality of the final product. Especially at high casting velocities, the bulging generates important level fluctuations which cannot be efficiently rejected by the classical controllers. To address these problems, this paper proposes an architecture combining disturbances estimation and compensation techniques. It operates as an additional module and does not need any change of the main controller currently implemented. The entire structure has been tested successfully through several simulations and by means of intensive water model experiments.  相似文献
10.
肖敏  史忠科 《自动化学报》2012,38(10):1609-1617
水雷水下发射攻击水上目标时出水瞬间数学模型发生突变, 严重影响水雷出 水的稳定性和打击概率, 对这一过程设计了滑模变结构单控制器和组合控制 器.利用微分几何的输入输出反馈线性化方法将非线性系统进行了线性化, 并利用变结构控制策略及趋近律算法设计了姿态跟踪闭环控制系统, 计算简便, 易于实现.对两种控制器的优劣性进行了比较, 通过数字仿真表明所设 计的控制系统可以适用于水下攻击目标出水突变过程, 并对系统参数摄动具 有较强的鲁棒性.  相似文献
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