拼铺法快速合成大规模植物分布

Tile-Based Rapid Authoring of Large-scale Plants

为了在构建大规模森林场景时快速而有效地在森林区域内分布大量的植物,提出一种基于Poisson disk tiles模型,通过样本块拼铺的方式快速合成大面积植物分布的方法.在样本集生成阶段,采用一种角匹配的方式,并配合Relaxation dart throwing算法来生成植物分布的样本块集合,从而克服了传统方法中的圆盘越界问题和顶角问题;在合成阶段,按照角匹配的方式,并采用直接随机拼铺的模式来快速合成视域范围内的植物分布,可满足大规模植被场景的实时合成与漫游要求.此外,提出一种合成植物多密度变化、多物种混合分布的方法,其采用一种分离策略,通过从高密度样本块中分离提取一部分样本点来生成多密度等级及多物种等级的子样本块集;根据所合成地区的密度信息和物种信息来选取合适的样本块集进行拼铺,从而合成带有密度变化及多物种混合的植物分布.在此基础上,实现了一个大规模森林场景的构建与漫游系统.实验结果表明,文中方法在构建大规模植物场景上是非常有效的,即使植物规模达到千万级,其合成效率也可以满足交互式应用的需求.

In order to synthesize large-scale plants in a virtual forest scene, this paper presents a real-time synthesismethod of large-scale plants by tilling the pre-generated samples based on Poisson disk tiles. In the samplegeneration phase, we adopt a corner matching manner and use the relaxation dart throwing algorithm to generatethe plants distribution in samples, with which we overcome the corner problem and disk crossing-border problemexisted in the traditional border matching method. In the synthesis phase, a corner-based direct stochastic tillingmethod is used to rapidly synthesize the distribution info in the current camera view, which can achieve areal-time performance when synthesizing large-scale plant distribution. Furthermore, this paper proposes a strategyfor synthesizing multi-species, non-uniform distributions of plants. With this strategy, multi-level sample setsare generated by extracting the sample subsets from the original high-density sample set. In the synthesis process,the right levels of samples will be selected for tilling according to the current species and density info on theuser-designed map, and then we synthesize the multi-species, multi-density distributions of plants. Based on themethod proposed in this paper, we have developed a forest scene modeling and roaming system. Experimentalresults show that the method is very efficient in the construction of large-scale forest scenes. Even when the number of plants reaches ten million, the synthesis can still be performed at an interactive rate.