基于分块地形的混合数据结构三维公路建模

摘要

In order to leverage the conflict between the dense data and the high performance of rendering in road embedded terrain, a hybrid modeling method based on tiled terrain is presented. This method combines the advantages of the two main methods regular grid and triangular irregular networks (TIN) on terrain modeling. If there is no road overlay a terrain block, the terrain block is roughly rendered by regular grid; Otherwise, the terrain block is rendered finely using the TIN. According to this method, the cracks caused by using LOD method are also eliminated by inserting point to the low level edge and a terrain cutting method based on directed line and moving step is also proposed. The experiment results show that this method is effective in the 3D road design.%为了权衡三维公路建模中数据高精度性以及渲染高效性的矛盾,在地形分块基础上提出了一种在场景中规则网格与不规则三角网并存的混合数据结构三维公路建模方法.此方法结合规则网格与不规则三角网两种地形表示方式的优缺点,若地形子块有公路覆盖,则利用Delaunay三角网方法精细绘制,否则基于规则网格LOD(细节层次)绘制,以此来提高渲染效率.针对此混合结构产生的决间裂缝问题,提出了对低细节层次节点增点的修补方案,以及针对此方法的特点提出了基于有向线段与增量步长的地形镂空算法,实现了地形与公路的无缝融合.实验结果表明,该方案可有效适用于三维公路设计.