Hybrid Grids for Sparse Volume Rendering

Shallow k-d trees are an efficient empty space skipping data structure for sparse volume rendering and can be constructed in real-time for moderately sized data sets. Larger volume data sets however require deeper k-d trees that sufficiently cull empty space but take longer to construct. In contrast to k-d trees, uniform grids have inferior culling properties but can be constructed in real-time. We propose a hybrid data structure that employs hierarchical subdivision at the root level and a uniform grid at the leaf level to balance construction and rendering times for sparse volume rendering. We provide a thorough evaluation of this spatial index and compare it to state of the art space skipping data structures.