【摘要】 为提高大型虚拟场景中树叶绘制速度和真实感,提出一种通过包含边缘轮廓和主叶脉的树叶草图生成三维树叶的方法.对轮廓点集进行均匀化和对称化预处理后,根据一定夹角找到轮廓点集与主叶脉点集间最短距离的点生成侧叶脉.叶面的整体弯曲根据主叶脉形态分为直线型或弯曲型两种,需要随主叶脉形态变换轮廓点集中点的位置实现.对由侧叶脉与主叶脉共同控制生成的叶面三角网格添加随机性扰动实现叶面的凸凹特征.进一步在此算法的基础上,通过缩小二维轮廓点、主叶脉点间的距离和减少点的数量的方法模拟树叶的动态生长;并在简单风场模型下,通过计算风力对轮廓、主叶脉的形变模拟树叶的风动特征.生成树叶结果逼真、数据量小,适合于树叶绘制量大的场景中使用.更多还原

【Abstract】 The method can generate three-dimensional leaf by a sketch of leaf outline and main vein. The points set of leaf outline is needed the pretreatment about uniform and symmetry. Then the lateral veins of leaf are calculated and produced from finding the shortest connection between leaf outline and main vein in accordance with a certain degree between secondary vein and main vein. In order to achieve the overall bent leaf,leaf outline is transformed in line with the main vein which is straight or has been bent. The roughness of leaf surface can be presented through adding a random position value to leaf surface meshes which is built by means of the corporation main vein and lateral veins. Based on this leaf modeling algorithm,Leaf growth is simulated by the way of decreasing the distance between points and the number of points in 2D outline set and main vein set. And in term of the assumption of simple wind moving,leaf outline and main vain showcertain deformation,then newleaf shape is shown with the wind moving changing. The realistic threedimensional leaf output,with a small amount of data,is more suitable for large scale scenes with numerous leaves in it.更多还原