Rendering large point clouds ordinarily requires building a hierarchical data structure for accessing the points that best represent the object for a given viewing frustum and level-of-detail. The building of such data structures frequently represents a large portion of the cost of the rendering pipeline both in terms of time and space complexity, especially when rendering is done for inspection purposes only. This problem has been addressed in the past by incremental construction approaches, but these either result in low quality hierarchies or in longer construction times. In this work we present OMiCroN -- Oblique Multipass Hierarchy Creation while Navigating -- which is the first algorithm capable of immediately displaying partial renders of the geometry, provided the cloud is made available sorted in Morton order. OMiCroN is fast, being capable of building the entire data structure in memory spending an amount of time that is comparable to that of just reading the cloud from disk. Thus, there is no need for storing an expensive hierarchy, nor for delaying the rendering until the whole hierarchy is read from disk. In fact, a pipeline coupling OMiCroN with an incremental sorting algorithm running in parallel can start rendering as soon as the first sorted prefix is produced, making this setup very convenient for streamed viewing.

中文翻译：

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OMiCroN -- 导航时创建倾斜多通道层次结构

渲染大型点云通常需要构建分层数据结构，以访问最能代表给定视锥和细节层次的对象的点。就时间和空间复杂性而言，构建此类数据结构通常占渲染管道成本的很大一部分，尤其是当渲染仅用于检查目的时。这个问题过去已经通过增量构建方法得到解决，但这些方法要么导致低质量的层次结构，要么导致更长的构建时间。在这项工作中，我们展示了 OMiCroN - 导航时倾斜多通道层次结构创建 - 这是第一个能够立即显示几何的部分渲染的算法，前提是云可以按莫顿顺序排序。OMiCroN 很快，能够在内存中构建整个数据结构所花费的时间与仅从磁盘读取云的时间相当。因此，不需要存储昂贵的层次结构，也不需要延迟渲染直到从磁盘读取整个层次结构。事实上，将 OMiCroN 与并行运行的增量排序算法耦合的管道可以在第一个排序前缀产生后立即开始渲染，这使得这种设置对于流式查看非常方便。