GPU-based Ray Casting of Stacked Out-of-Core Height Fields

We developed a ray casting-based rendering system for the visualization of geological subsurface models consisting of multiple highly
detailed height fields. Based on a shared out-of-core data management system, we virtualize the access to the height fields, allowing us to treat the individual surfaces at different local levels of detail. The visualization of an entire stack of height-field surfaces is accomplished in a single rendering pass using a two-level acceleration structure for efficient ray intersection computations. This structure combines a minimum-maximum quadtree for empty-space skipping and a sorted list of depth intervals to restrict ray intersection searches to relevant height fields and depth ranges. We demonstrate that our system is able to render multiple height-fields consisting of hundreds of millions of points in real-time.