三维模型表面特征的水墨效果渲染算法

提出一种对三维模型实现水墨效果渲染的两步二维纹理映射方法.该方法首先通过模型顶点的视线向量和法线向量的点乘积计算其夹角的余弦值,作为第一步的纹理坐标进行映射;再通过欧拉公式计算径向曲率及其方向导数值,作为第二步映射的纹理坐标.为达到实时的交互浏览,在第二步映射时还可采用基于视点无关的曲率特征的映射策略(如平均曲率、高斯曲率、主曲率等).在快速生成水墨画效果的同时也显示出更多的特征细节.

Chinese-Painting Style Rendering for Surface Features on 3D Models

We present a two-pass texture mapping procedure to produce Chinese-painting style image for 3D model. By the procedure, we first use the cosine values of the angle between view vector and normal vector on each vertex as the texture coordinates, through calculation of the dot product of the two vectors. The derivative of radial curvature on the model surface is used as the second pass texture mapping coordinates, by a calculation using Euler formula. To improve rendering speed, we explore other rendering strategies in the second pass mapping based on view-independent curvature values such as mean curvature, Gaussian curvature, or principle curvature. Our algorithm can not only rerider the model efficiently in Chinese-painting style, but also often show additional feature of the 3D model.