A hybrid level-of-detail representation for large-scale urban scenes rendering

A novel hybrid level-of-detail (LOD) algorithm is introduced. We combine point-based, line-based, and splat-based rendering to synthesize large-scale urban city images. We first extract lines and points from the input and provide their simplification encoded in a data structure that allows for a quick and automatic LOD selection. A screen-space projected area is used as the LOD selector. The algorithm selects lines for long-distance views providing high contrast and fidelity of the building silhouettes. For medium-distance views, points are added, and splats are used for close-up views. Our implementation shows a 10 speedup as compared with the ground truth models and is about four times faster than geometric LOD. The quality of the results is indistinguishable from the original as confirmed by a user study and two algorithmic metrics. Copyright © 2014 John Wiley & Sons, Ltd.