【摘要】：柔軟織物與我們的生活息息相關(guān),因此它成為了虛擬現(xiàn)實(shí)技術(shù)中一類重要的仿真對象。早在19世紀(jì)80年代,研究人員便開始關(guān)注基于物理的柔軟織物的仿真研究。經(jīng)過30多年的發(fā)展,廣泛應(yīng)用于游戲娛樂、影視動(dòng)畫、服裝設(shè)計(jì)等多個(gè)領(lǐng)域。盡管柔軟織物仿真的相關(guān)技術(shù)已經(jīng)非常豐富,在某些方面,依舊面臨巨大挑戰(zhàn),比如如何提升模擬織物的褶皺細(xì)節(jié)時(shí)的時(shí)間性能。而為了在不損失真實(shí)度的條件下顯著提高仿真的時(shí)間性能,人們開始越來越多地關(guān)注基于GPUs對布料仿真進(jìn)行并行化仿真的研究。本文便旨在基于CUDA架構(gòu)對柔軟織物仿真的相關(guān)算法進(jìn)行并行化,優(yōu)化仿真系統(tǒng)的時(shí)間性能。論文從以下幾個(gè)方面進(jìn)行展開:首先,介紹了柔軟織物仿真相關(guān)的軟件和硬件技術(shù)以及并行化編程的基礎(chǔ),例如GPU并行編程的硬件架構(gòu)及并行編程思想等。為后面對數(shù)值解算及碰撞檢測算法的并行化提供了理論依據(jù)。然后分為幾個(gè)部分介紹仿真系統(tǒng)的主要構(gòu)成部分及其算法研究。第一步為對柔軟織物物理建模。并通過對比分析目前主流的三種柔軟織物建模方法,選擇了物理建模技術(shù)作為本文的重點(diǎn)研究方法。接下來詳細(xì)描述物理建模方法中的質(zhì)點(diǎn)-彈簧系統(tǒng)理論,從模型的構(gòu)建、系統(tǒng)的受力分析兩個(gè)方面闡述質(zhì)點(diǎn)-彈簧系統(tǒng),并分析解決質(zhì)點(diǎn)-彈簧系統(tǒng)的“超彈性”問題。然后,對比質(zhì)點(diǎn)彈簧模型的幾種動(dòng)力學(xué)積分解算方法,選擇了易于進(jìn)行并行化設(shè)計(jì)且相對較為穩(wěn)定、高效的Verlet積分法。最后對Verlet積分法的并行化做了研究,提出共享內(nèi)存與線程的動(dòng)態(tài)映射方法以保證了并行化計(jì)算時(shí)的負(fù)載均衡。接下來是柔軟織物仿真系統(tǒng)中的碰撞檢測部分進(jìn)行并行化。首先介紹并對比幾種常用的碰撞檢測方法,結(jié)合柔軟織物易形變的特性,最終選擇了 AABB層次包圍盒方法。然后針對AABB層次樹,提出了一種改進(jìn)的二叉基數(shù)布局方法,以便能夠用完全并行的方法創(chuàng)建AABB包圍盒的層次結(jié)構(gòu),以及AABB包圍盒的計(jì)算。另外,通過改進(jìn)遍歷樹的并行遞歸算法,實(shí)現(xiàn)了并行迭代遍歷算法,極大提升了該部分的時(shí)間性能。最后,給出基于CUDA柔軟織物仿真系統(tǒng)的實(shí)現(xiàn)結(jié)果。為了便于分析論文中提出的數(shù)值解算及碰撞檢測算法各自對系統(tǒng)性能的影響,通過設(shè)計(jì)合適的仿真場景,分別針對這兩個(gè)算法進(jìn)行了實(shí)驗(yàn),并給出了用于對比的串行實(shí)現(xiàn)結(jié)果。最后是整個(gè)系統(tǒng)的仿真實(shí)現(xiàn)結(jié)果。
[Abstract]:Soft fabric is closely related to our lives, so it has become an important simulation object in virtual reality technology. As early as the 1880s, researchers began to focus on physical-based simulation of soft fabrics. After more than 30 years of development, widely used in games and entertainment, film and television animation, clothing design and many other fields. Although the technology of soft fabric simulation is very rich, there are still great challenges in some aspects, such as how to improve the time performance of the wrinkle details of the simulated fabric. In order to improve the time performance of simulation without loss of authenticity, people pay more and more attention to the parallel simulation of cloth simulation based on GPUs. The aim of this paper is to parallelize the algorithms of soft fabric simulation based on CUDA architecture to optimize the time performance of the simulation system. The thesis is carried out from the following aspects: firstly, the software and hardware technologies related to soft fabric simulation and the basis of parallel programming, such as the hardware architecture of GPU parallel programming and the idea of parallel programming, are introduced. It provides a theoretical basis for later numerical solution and parallelization of collision detection algorithm. Then it is divided into several parts to introduce the main components of the simulation system and its algorithm research. The first step is the physical modeling of soft fabrics. By comparing and analyzing the three mainstream soft fabric modeling methods, the physical modeling technology is chosen as the key research method in this paper. Secondly, the theory of particle-spring system in physical modeling method is described in detail. The particle-spring system is expounded from two aspects: the construction of model and the force analysis of the system, and the problem of "hyperelasticity" of particle-spring system is analyzed and solved. Then, by comparing several dynamic integral solutions of particle spring model, a relatively stable and efficient Verlet integration method is selected, which is easy to parallel design and is relatively stable. Finally, the parallelization of Verlet integration method is studied, and a dynamic mapping method between shared memory and thread is proposed to ensure the load balancing in parallel computation. Then the collision detection part of the soft fabric simulation system is parallelized. Firstly, several commonly used collision detection methods are introduced and compared. Combined with the deformation-prone characteristics of soft fabrics, the AABB hierarchical bounding box method is finally selected. Then, an improved binary cardinality layout method for AABB hierarchical tree is proposed, so that the hierarchical structure of AABB bounding box and the calculation of AABB bounding box can be created by completely parallel method. In addition, the parallel iterative traversal algorithm is implemented by improving the parallel recursive algorithm of traversal tree, which greatly improves the time performance of this part. Finally, the results of soft fabric simulation system based on CUDA are given. In order to analyze the influence of the numerical solution and collision detection algorithm on the performance of the system, the experiments of the two algorithms are carried out by designing suitable simulation scenes, and the serial implementation results for comparison are given. Finally, the simulation results of the whole system are given.
【學(xué)位授予單位】：哈爾濱工程大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2016
【分類號(hào)】：TP391.9;TS101.9

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本文編號(hào)：2452384