关键词: 双层次细节, 过渡带, 地形网格

Abstract: A two levels of detail terrain is presented in this paper.During the lower Level Of Detailed（LOD） terrain，we simply render the whole terrain using ROAM mesh independent of view.During the high LOD terrain，we render the fluctuant detail of terrain’s height using symmetrical mesh along view center.We control upper LOD terrain’s range by adjusting projective area proportion between upper LOD terrain and the whole terrain.Transitional area of the two level terrain is pushed away from the view.Based on the resolution difference between lower level and upper level，we calculate the transitional area’s width，and ensure the two LOD terrain’s smooth transition by rendering the areal color based on image special Per-Pixel displacement texture method.

Key words: two levels of detail, transitional area, terrain mesh