Interactive visualization of the largest radioastronomy cubes

3D visualization is an important data analysis and knowledge discovery tool, however, interactive visualization of large 3D astronomical datasets poses a challenge for many existing data visualization packages. We present a solution to interactively visualize larger-than-memory 3D astronomical data cubes by utilizing a heterogeneous cluster of CPUs and GPUs. The system partitions the data volume into smaller sub-volumes that are distributed over the rendering workstations. A GPU-based ray casting volume rendering is performed to generate images for each sub-volume, which are composited to generate the whole volume output, and returned to the user. Datasets including the HI Parkes All Sky Survey (HIPASS -- 12GB) southern sky and the Galactic All Sky Survey (GASS -- 26GB) data cubes were used to demonstrate our framework's performance. The framework can render the GASS data cube with a maximum render time <0.3 s with 1024 x1024 pixels output resolution using three rendering workstations and eight GPUs. Our framework will scale to visualize larger datasets, even of Terabyte order, if proper hardware infrastructure is available.