Volumetric modeling with diffusion surfaces
Volumetric modeling with diffusion surfaces
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DOI：
10.1145/1866158.1866202
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发表时间：
2010-12
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影响因子：
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通讯作者：
Kenshi Takayama;O. Sorkine-Hornung;Andrew Nealen;T. Igarashi
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文献类型：
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作者：
Kenshi Takayama;O. Sorkine-Hornung;Andrew Nealen;T. Igarashi
体对象的建模仍然是一个难题。实体纹理合成方法可以设计具有均匀纹理的体积，但蔬菜和水果中看到的平滑变化的颜色等全局特征很难建模。在本文中，我们提出了一种称为扩散曲面(DSS)的表示法来对此类对象进行建模。DSS由在两侧定义了颜色的3D曲面组成，因此体积中的内部颜色是通过从附近曲面扩散颜色来获得的。计算颜色扩散的一种直接方法是以DSS的颜色为边界条件求解体积泊松方程，但这需要昂贵的体积网格，这不适合交互建模。因此，我们建议仅在用户定义的横截面上使用修改版本的正均值坐标算法来局部地内插颜色，以避免体积网格。决策支持系统一般适用于对具有内部结构的多种不同类型的对象进行建模。作为一个案例研究，我们提供了一个简单的基于草图的界面，用于建模具有旋转对称的对象，该界面还可以生成模型的随机变化。我们通过各种DSS模型和DSS支持的简单的非照片级真实感绘制技术来演示我们的方法的有效性。
The modeling of volumetric objects is still a difficult problem. Solid texture synthesis methods enable the design of volumes with homogeneous textures, but global features such as smoothly varying colors seen in vegetables and fruits are difficult to model. In this paper, we propose a representation called diffusion surfaces (DSs) to enable modeling such objects. DSs consist of 3D surfaces with colors defined on both sides, such that the interior colors in the volume are obtained by diffusing colors from nearby surfaces. A straightforward way to compute color diffusion is to solve a volumetric Poisson equation with the colors of the DSs as boundary conditions, but it requires expensive volumetric meshing which is not appropriate for interactive modeling. We therefore propose to interpolate colors only locally at user-defined cross-sections using a modified version of the positive mean value coordinates algorithm to avoid volumetric meshing. DSs are generally applicable to model many different kinds of objects with internal structures. As a case study, we present a simple sketch-based interface for modeling objects with rotational symmetries that can also generate random variations of models. We demonstrate the effectiveness of our approach through various DSs models with simple non-photorealistic rendering techniques enabled by DSs.