Scalable Interactive Ray-Casting of Volumes Using Off-the-Shelf Components

This paper describes an application of the second generation Sepia architecture implementation (Sepia-2) to support interactive visualization of scalar fields represented as very large 3D rectilinear grids. By employing pipelined sort-last associative blending operators a demonstration system yields scalable interactivity at 30 frames per second. We believe these results can be extended to support other types of structured and unstructured grids and a variety of GL rendering techniques. We show how to extend our single-stage demonstration system to larger multi-stage networks. This requires solving a dynamic mapping problem for blending operators that are similar to Porter-Duff compositing operators. We conclude by discussing technical and fundamental issues to address in future work.