3D模型非真实感绘制效果若干问题研究

发布时间：2018-06-24 01:52

本文选题：非真实感绘制 + 轮廓线风格化　；参考：《陕西师范大学》2011年硕士论文

【摘要】：非真实感绘制(Non-Photorealistic Rendering, NPR)是计算机技术和绘画艺术相结合的研究领域,它着眼于对真实的场景进行抽象和加工,以突出其中的重要信息,使人获得更直观和更深刻的印象,因而它在教育、娱乐、艺术等领域有广泛的应用前景。虽然基于图像的非真实感绘制研究比较多,但基于3D模型的非真实感绘制研究相对比较缺乏。在3D物体的非真实感绘制中,轮廓线有效提取与风格化、模型的渲染等是关键,本文正是基于这些关键问题的开展的研究,可概括为： (1)轮廓线的凸现与绘制三维模型的轮廓线检测是非真实感绘制的一个基础问题。轮廓线刻画了三维模型的基本外观,对于三维物体的感知和审美都是必须的,也关系到非真实感绘制的最终效果。本文利用网格锐化的思想,对三维网格模型进行预处理,使模型的特征更加突出,并集合简单的轮廓线探测算法提取了更多的特征线。另外,实现了启发式轮廓的提取,更生动的表达了模型的形状特征。 (2)轮廓线的风格化风格化轮廓线是非真实感绘制中一种重要的艺术表现形式。本文首先通过三维网格模型的锐化处理获得更多的特征线,在此基础上对特征线进行风格化,增强了轮廓线的表现力；其次,提出了一种计算量少的风格化算法,即特征线的两个端点沿顶点法向量方向按用户定义的权重扩张成四边形,然后进行纹理映射,以达到不同的绘制效果；同时实验表明,该方法也可以较好地保持特征线之间的连续性。 (3)三维模型的渲染首先,本文给出了一种卡通渲染的改进方法。引入曲率等几何分量,对传统的卡通渲染进行改进。替代传统的利用线条来刻画模型的形状特征,本文利用平均曲率作为一维纹理的坐标对三维模型进行渲染,基于该方法,可以很好的描绘出三维网格模型的大致形状和内部特征。其次,本文给出了一种基于径向曲率的卡通渲染改进方法。本文针对三维网格模型卡通渲染效果有限,并且不能显示模型内部特征等缺点,引入与视点相关的径向曲率,对X-Toon绘制算法进行改进,给出了基于径向曲率的渲染方法,该方法不仅可以解决内部细节特征问题,而且可以模拟多种材质效果,如金属、水彩、水粉等。本文这些方法在动漫影视、三维动画造型、出版物制作等领域具有良好的借鉴意义和应用价值。
[Abstract]:Non-Photorealistic rendering (NPR) is a research field that combines computer technology and painting art. It focuses on abstracting and processing real scenes in order to highlight the important information and make people more intuitive and impressive. Therefore, it has a wide application prospect in the fields of education, entertainment, art and so on. Although there are many researches on non-realistic rendering based on image, the research on non-realistic rendering based on 3D model is relatively lacking. In the non-realistic rendering of 3D objects, the effective extraction and stylization of contour lines and rendering of models are the key points. This paper is based on the research of these key problems. It can be summarized as follows: (1) the protruding of contour line and the detection of contour line in rendering 3D model are a basic problem in non-realistic rendering. The outline depicts the basic appearance of the 3D model, which is necessary for the perception and aesthetic of the 3D object, and also relates to the final effect of the non-realistic rendering. Using the idea of mesh sharpening, this paper preprocesses the 3D mesh model to make the feature of the model more prominent, and gathers the simple contour detection algorithm to extract more feature lines. In addition, the heuristic contour extraction is realized, and the shape feature of the model is more vividly expressed. (2) the stylized contour line is an important artistic expression in non-realistic rendering. In this paper, firstly, more feature lines are obtained by sharpening the 3D mesh model, and then the feature lines are stylized to enhance the expression of contour lines. Secondly, a stylized algorithm with less computation is proposed. That is, the two endpoints of the feature line expand into quadrilateral along the normal vector direction of the vertex according to the weight defined by the user, then texture mapping is carried out to achieve different rendering effects. At the same time, the experimental results show that, The method can also maintain continuity between feature lines. (3) rendering of 3D models. Firstly, an improved method of cartoon rendering is presented in this paper. The traditional cartoon rendering is improved by introducing geometric components such as curvature. Instead of the traditional use of lines to depict the shape features of the model, this paper uses the mean curvature as the coordinate of one-dimensional texture to render the 3D model. The approximate shape and internal features of the three-dimensional mesh model can be well described. Secondly, an improved method of cartoon rendering based on radial curvature is presented. In this paper, aiming at the shortcomings of cartoon rendering of 3D mesh model, such as limited effect and unable to display the internal features of the model, this paper introduces the radial curvature related to the viewpoint, improves the X-Toon rendering algorithm, and presents the rendering method based on radial curvature. This method can not only solve the problem of interior details, but also simulate many kinds of material effects, such as metal, watercolor, water powder and so on. These methods have good reference significance and application value in the field of animation, film and television, 3D animation modeling, publication production and so on.
【学位授予单位】：陕西师范大学
【学位级别】：硕士
【学位授予年份】：2011
【分类号】：TP391.41

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