Out-of-core rendering of massive data sets

Abstract

With the advancement in computer-aided design technologies and 3D capturing devices, complex realistic geometric models can be created that can contain millions of triangles. Examples of such models include architectural buildings, complex CAD structures and 3D scans of heritage sites. These 3D models pose a number of challenges to current graphic systems when used for interactive display and manipulation. In this work we make use of out-of-core techniques in order to enable rendering of massive data sets. Our rendering framework makes use of ray-casting and an acceleration data structure. The algorithm renders models without the need to load them entirely into memory. Models are first added into the framework and organized onto a tree-based acceleration data structure with the leaves containing the models' data. Depending on memory availability, two caches arc created inside the main memory, one for the acceleration structure and another for the data stored at the leaf nodes. Various replacement policy heuristics are tested. Each heuristic has a different policy on how the data is managed and replaced inside the caches to determine the best approach in different scenes. Figure 38 found in the Results and Evaluation section shows a series of rendered images by our system of the power plant model downloaded from [24]. This model contains about 12 million triangles and each 512*512 image is rendered in about 21 seconds using the LRU cache replacement policy.