中文摘要：

提出了一种新的建筑物阴影快速模拟算法．首先根据不同时刻的太阳位置，采用一种基于投影的多边形搜索算法计算光源坐标系下三维建筑物的阴影外轮廓，包括本影和软影区域，然后计算阴影区内的光亮度，将阴影图投射到地面上，最后基于多边形的填充算法实时绘制出任意时刻的建筑物阴影效果．

英文摘要：

A new method to real-time simulate architecture shadows is proposed. Firstly, we calculate the positions of sun in different times, and calculate the silhouettes of buildings in the sunlight coordinate, including the umbra and soft shadow. Then we calculate the grayscale of shadow, and map the shadow map on the ground. Finally, through the filling algorithm based on polygon, we generate different architecture shadows at different times in real time.