基于高斯球的近似共面合并层次细节模型

构造场景多层次细节模型是加速图形显示的有效途径.给出一种基于共面合并自动生成场景多层次细节模型的算法.此算法将一单位球定义为高斯球,并按一定的规则对其进行层次分割.然后根据各景物面片的法向在高斯球上的分布,将具有近似一致法向的面片划分为面片族;在面片族内对相邻面片进行合并,生成近似共面区域;然后移去其内部点,对区域边界重新三角化.算法还结合临近边界点合并等原则,删除对表达场景几何特征重要度低的顶点.算法利用平面九叉树进行合并操作,生成具有多层次细节的场景模型.实验结果表明,算法能实现较理想的场景简化效果.

A Level of Detail Model by Merging Near-Coplanar Faces Based on Gauss Sphere

Multiple LOD modeling is an effective approach to speed up the rendering of 3D scenes. An algorithm that creates multiple levels of detail for 3D scene by merging near-coplanar faces is presented in this paper. First a Gauss sphere is defined for the modeling of the scene, which is divided into patches uniformly. Faces of objects in the scene are then attached to the respective spherical patches according to their normal direction. If faces attached to the same patch are adjacent to each other, they are merged to form a near coplanar area (superface). Isolated vertices inside the area are removed and the area is retriangularized. To further improve the simplification, vicinity vertices on the border of the area are merged. The algorithm adopts a planar separation rule to support the hierarchical model. The experimental result shows that the algorithm can achieve the desired simplification effect.