本文選題：網(wǎng)格變形 + 模型分塊��； 參考：《杭州電子科技大學》2011年碩士論文

【摘要】：’網(wǎng)格變形是三維模型處理領(lǐng)域中的重要組成部分,它是近幾年來計算機圖形學中的研究熱點之一,很多研究成果已經(jīng)得到了廣泛的應(yīng)用,如動畫制作,影視廣告,以及計算可視化等領(lǐng)域。網(wǎng)格變形大體可分為兩類：一類是基于能量優(yōu)化,另一類是基于插值重構(gòu)。前者屬于間接變形,速度較快、效果較好,但是變形不易控制,且適用范圍較窄；后者則具有較強的操作性,算法簡單實用,但效率不高而且容易失真。根據(jù)上述兩類算法的優(yōu)劣性,衍生出結(jié)合多種方法的混合變形技術(shù),已成為近年來網(wǎng)格變形的發(fā)展趨勢。本文針對插值重構(gòu)方法中最流行的提取模型輪廓特征線來重構(gòu)變形曲面的方法進行了相關(guān)研究,主要作了以下三個方面的工作。 第一,研究了形狀直徑函數(shù)(Shape Diameter Function,簡稱SDF)值的模型分塊技術(shù),并在此基礎(chǔ)上實現(xiàn)了一種利用K-D樹空間劃分的網(wǎng)格模型分塊方法。該方法利用K-D樹的空間劃分,通過它的每一層檢測不同的屬性(關(guān)鍵字)值來決定選擇分枝的方向,使劃分后的模型塊與物體的實際結(jié)構(gòu)相吻合。與傳統(tǒng)的利用SDF值模型分塊方法相比,本文給出的算法在一定程度上增加了模型分塊的有效性,同時又為后期的骨骼線提取打下了良好的基礎(chǔ)。 第二,通過基于K-D樹空間劃分的SDF值模型分塊,給出了一種網(wǎng)格模型骨骼線和模型輪廓特征線的提取方法。模型輪廓特征線變形由于其自身提取困難,比較適合于給定特征線參數(shù)值的情況,且變形范圍較窄。而單純的使用骨骼線驅(qū)動變形又容易出現(xiàn)不自然的效果。本文通過把網(wǎng)格模型輪廓特征線結(jié)合到模型骨骼線上,讓骨骼線變形的易于操縱、簡單實用等優(yōu)勢和特征線變形保持細節(jié)的優(yōu)勢結(jié)合起來,增強網(wǎng)格模型的變形效果。 第三,提出了一種用輪廓線作為邊界條件,然后利用偏微分方程來實現(xiàn)動態(tài)曲面重構(gòu)方法。由于偏微分方程構(gòu)造曲面簡單易行,只需給定曲面的邊界及其上的跨界導矢,即可生成光滑曲面。因此,本文通過在偏微分方程表示的曲面輪廓線中引入變形參數(shù)來代替點關(guān)聯(lián)的方法,實現(xiàn)動態(tài)曲面重構(gòu)。實驗結(jié)果表明,本文方法所重構(gòu)出的變形曲面自然連貫且客觀真實,可應(yīng)用于藝術(shù)曲面造型設(shè)計中。
[Abstract]:Grid deformation is an important part of 3D model processing field. It is one of the research hotspots in computer graphics in recent years. Many research results have been widely used, such as animation production, film and television advertising, And computational visualization and other fields. Mesh deformation can be divided into two categories: one is based on energy optimization, the other is based on interpolation reconstruction. The former belongs to indirect deformation, the speed is faster, the effect is better, but the deformation is not easy to control, and the scope of application is narrow; the latter has strong maneuverability, simple and practical algorithm, but low efficiency and easy distortion. According to the advantages and disadvantages of the above two algorithms, the hybrid deformation technology combined with many methods has become the development trend of grid deformation in recent years. In this paper, the most popular method of extracting the contour feature line of the model to reconstruct the deformable surface is studied in this paper. The main work is as follows. Firstly, the model partitioning technique of shape Diameter function (SDFs) of shape Diameter function is studied, and a mesh model block method based on K-D tree space is implemented. This method uses the space partition of K-D tree to determine the direction of branch selection by detecting different attribute (keyword) values in each layer of K-D tree, which makes the partitioned model block coincide with the actual structure of the object. Compared with the traditional block method using SDF value model, the algorithm in this paper increases the validity of the model to some extent, and lays a good foundation for the later skeleton line extraction at the same time. Secondly, by dividing the SDF value model into blocks based on K-D tree space, a method of extracting the skeleton line and the contour feature line of the mesh model is presented. Because of the difficulty of extracting the contour feature line of the model, it is more suitable for the given parameter value of the feature line, and the deformation range is narrow. But the simple use of bone lines to drive deformation is prone to unnatural effects. In this paper, the mesh model contour feature line is combined with the model skeleton line, so that the deformation of the bone line can be easily manipulated, simple and practical, and the advantages of keeping the detail of the feature line deformation can be combined to enhance the deformation effect of the mesh model. Thirdly, a dynamic surface reconstruction method using contour as boundary condition and partial differential equation is proposed. Due to the simple construction of surface by partial differential equation, the smooth surface can be generated only by giving the boundary of the surface and its cross boundary derivative vector. Therefore, in this paper, the dynamic surface reconstruction is realized by introducing the deformation parameter into the contour of the curved surface represented by partial differential equation instead of the point correlation method. The experimental results show that the deformed surface reconstructed by this method is naturally coherent and objective, and can be applied to the design of artistic surface modeling.
【學位授予單位】：杭州電子科技大學
【學位級別】：碩士
【學位授予年份】：2011
【分類號】：TP391.41

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本文編號：1955250