Sparse Volume Rendering using Hardware Ray Tracing and Block Walking

We propose a method to render sparse volumetric data using ray-tracing hardware efficiently. To realize this, we introduce a novel data structure, traversal algorithm, and density encoding that allows for an annotated BVH representation. In order to avoid API calls to ray tracing hardware which reduces the efficiency in the rendering, we propose the block walking for which we store information about adjacent nodes in each BVH node’s corresponding field, taking advantage of the knowledge of the content layout. Doing so enables us to traverse the tree more efficiently without repeatedly accessing the spatial acceleration structure maintained by the driver. We demonstrate that our method achieves higher performance and scalability with little memory overhead, enabling interactive rendering of volumetric data.