Distributed terascale volume visualization using distributed shared virtual memory

Each cluster node is running its own pipeline for ray-casting, virtual vol- ume and memory management, and paging. Ray-casting is per- formed on a huge virtual 3D volume, which is conceptually given on a regular grid in 3D. However, this volume is virtual because the data that are sampled by the ray-caster are only created on demand (i.e., read from disk or reconstructed on-the-fly), as determined by the actual visibility of small cubical blocks or memory pages of 32 voxels each. In order to be able to adapt the data resolution used for ray-casting to the output screen resolution, we represent the whole virtual volume as a virtual octree multi-resolution hier- archy, which is mapped to a large shared virtual memory address space.