基于粒子系统的不规则景物建模研究

发布时间：2018-04-09 22:38

本文选题：粒子系统　切入点：景物模拟　出处：《山东师范大学》2009年硕士论文

【摘要】： 如何逼真地模拟自然景物一直是图形学中的一个热门研究课题和难点问题。火焰、云烟、雨滴、雪花等动态自然景物的模拟,在航空航天、影视广告、虚拟场景中有着广泛的应用。然而大多数景物的外形是随机变化的,很难用常规的建模方法及模拟技术来描述。因此自然景物的模拟一直以来都是计算机图形学领域研究的热点和重点。随着近年来研究的不断深入,各种自然景物模拟算法不断涌现,模拟结果也越来越具有真实感。其中,粒子系统方法是迄今为止被认为模拟不规则模糊自然景物最为成功的一种生成算法。本文基于粒子系统,对自然界中不规则景物——火焰,降雨等分别进行了模拟,首先,介绍了粒子系统的基本理论,着重讲解粒子系统构造模型的基本方法,把粒子系统实际运作分为粒子属性确立、粒子产生、粒子更新、粒子绘制等几个步骤,并对每个操作步骤进行详细说明将粒子系统分为质点系模型系统和流质系模型系统,阐述这两种模型系统的特点列举了两个质点系模型粒子系统的例子,对这两个例子按照前面所讲粒子系统运作步骤逐步讲解,展示每一步的操作细则,最后论述在粒子渲染时所用到的图形学技术。其次,深入讨论了基于粒子系统的火焰模拟方法,详细讨论了火焰模型中火焰粒子属性的初始化及其变化,包括火焰粒子的形状、大小、颜色、透明度、位置、速度、生命期等,并且讨论了火焰粒子的运动和绘制。采用面向对象的思想建立了粒子系统和粒子的数据结构。设计了火焰模拟系统的功能模块,将该系统划分为四个模块粒子系统模块、粒子模块、纹理模块和运动场模块。在火焰绘制过程中,为了增强真实感,采用了纹理映射技术、公告板技术、混色处理技术。特别是为了表现火焰来回左右上下跳动的动态摇曳效果,在系统中增加了运动场。在运动场中重点讨论了重力和风力对火焰的影响。为了提高实时性,在火焰粒子绘制中,一是采用四角面片代替点粒子的绘制方法,这样每一个面片可以代替几百个粒子二是采用动态生成视点替用特效技术,提高了系统的运行速度。在论文的最后,探讨了提高粒子系统实时性的方法。再次,简单介绍了基于粒子系统的其他不规则自然景物降雨的模拟方法,并对雨粒子模型在实际中的应用做了相关说明,同时还介绍了在降雨模拟中提高逼真度的相关辅助补偿方法。然后,论文设计了一个基于粒子系统的演示系统,采用VC++6.0为编程工具,三维动画环境由OpenGL支持,实现了论文提出的对不规则景物的模拟。最后,总结和分析本论文研究的意义和应用的成果,对论文的进一步研究方向提出了几点想法。并且展望了粒子系统及本论文的不规则景物模拟模型应用的前景,浅谈了关于粒子系统在不自然景物建模中实时性,真实感的创新与改进的几点想法。
[Abstract]:How to simulate natural scenery vividly has always been a hot research topic and difficult problem in graphics.Fire, smoke, raindrops, snowflakes and other dynamic natural scenery simulation, in aerospace, film and television advertising, virtual scene has a wide range of applications.However, the shape of most scenes is random and difficult to describe by conventional modeling methods and simulation techniques.Therefore, the simulation of natural scenery has always been a hot spot and focus in the field of computer graphics.With the development of research in recent years, a variety of natural scene simulation algorithms are emerging, and the simulation results are more and more realistic.Particle system method is considered to be the most successful algorithm to simulate irregular fuzzy natural scene.Based on particle system, this paper simulates the irregular scenery in nature, such as flame, rainfall and so on. Firstly, the basic theory of particle system is introduced, and the basic method of constructing model of particle system is explained emphatically.The actual operation of particle system is divided into several steps, such as particle attribute establishment, particle generation, particle renewal, particle drawing and so on. The particle system is divided into particle system model system and fluid system model system.The characteristics of these two model systems are described. Examples of two particle systems of particle systems are given. The two examples are explained step by step according to the operational steps of the particle system described earlier, and the operational details of each step are displayed.Finally, the graphics techniques used in particle rendering are discussed.Secondly, the flame simulation method based on particle system is discussed in depth, and the initialization and change of flame particle properties in flame model are discussed in detail, including the shape, size, color, transparency, position, speed of flame particle.Life cycle and so on, and discussed the motion and drawing of flame particles.The object-oriented idea is used to establish the particle system and the particle data structure.The function module of flame simulation system is designed. The system is divided into four modules: particle system module, particle module, texture module and sports field module.In the process of flame rendering, texture mapping technology, bulletin board technology and mixed color processing technology are adopted in order to enhance the sense of reality.Especially in order to show the dynamic flickering effect of the flame up and down, the sports field is added in the system.The influence of gravity and wind on the flame was discussed in the stadium.In order to improve the real-time performance of flame particle rendering, one of the methods is to replace the point particle with a quadrangular slice, so that each surface slice can replace hundreds of particles and the second is to use the dynamic generation viewpoint technology to replace the special effect technology.The running speed of the system is improved.At the end of the paper, the methods to improve the real-time performance of particle system are discussed.Thirdly, the simulation method of other irregular natural scenery rainfall based on particle system is briefly introduced, and the application of rain particle model in practice is explained.At the same time, the related auxiliary compensation method to improve the fidelity in rainfall simulation is introduced.Then, a demonstration system based on particle system is designed, which uses VC 6.0 as programming tool, and 3D animation environment is supported by OpenGL to realize the simulation of irregular scene.Finally, the significance and application of this paper are summarized and analyzed.The prospect of particle system and the application of irregular scene simulation model in this paper are prospected, and some ideas about the real time, real time and improvement of particle system in the modeling of unnatural scene are discussed.
【学位授予单位】：山东师范大学
【学位级别】：硕士
【学位授予年份】：2009
【分类号】：TP391.41

【引证文献】