| This research introduces Volume Scene Graphs—a novel, flexible, and scalable software architecture for composing complex volumetric scenes containing multiple, large, out-of-core volume data sets for scientific visualization. The Volume Scene Graph ( VSG) System and its Volume Shading Language (VSL) provide control over scene content and the manipulation of multiple larger-than-core overlapping data sets. The system uses a fine-grain data-pull style that pulls data from the scene on-demand for use in data filtering and volume rendering. For large data sets, this approach achieves better compute performance and storage use than traditional scene graph and visualization data-flow designs.; The VSG System manages a hierarchical scene graph data structure that contains both shapes and filtering operations. The design presents a shape-manipulation metaphor that enables users to think of building a scene as a process of arranging and grouping shapes. Built-in filtering operations transform those shapes by applying transfer functions and compositing operators.; The arrangement of shapes and operators of the volume scene graph are defined by volume shaders written in the system's Volume Shading Language. Rendering the volume scene executes the shaders, processing data on-demand and in parallel to achieve performance that scales well with data size, scene size, and available compute resources. |
