Direct Volume Rendering of Stack-Based Terrains

Abstract

Traditionally, the rendering of volumetric terrain data, as many other scientific 3D data, has been carried out performing direct volume rendering techniques on voxel-based representations. A main problem with this kind of representation is its large memory footprint. Several solutions have emerged in order to reduce the memory consumption and improve the rendering performance. An example of this is the hierarchical data structures for space division based on octrees. Although these representations have produced excellent outcomes, especially for binary datasets, their use in data containing internal structures and organized in a layered style, as in the case of surface-subsurface terrain, still leads to a high memory usage. In this paper, we propose the use of a compact stack-based representation for 3D terrain data, allowing a real-time rendering using classic volume rendering procedures. In contrast with previous work that used this representation as an assistant for rendering purposes, we suggest its use as main data structure maintaining the whole dataset in the GPU in a compact way. Furthermore, the implementation of some visual operations included in geoscientific applications such as borehole visualization, attenuation of material layers or cross sections has been carried out.