ParVox is a parallel three-dimensional volume rendering system capable of visualization of large time-varying earth science datasets in structured and unstructured grids. In addition, ParVix is a distributed visualization system that allows users to control the parallel renderer on a remote supercomputer using user's desktop workstation and view the results interactively.

ParVox is equipped with an X window based GUI program for display and viewing control, two input modules that read structured and unstructured 4D datasets in NetCDF format, respectively, two core renderers, one for structured grid datasets and one for unstructured grid dataset, and an output module that supports multiple output formats, including a wavelet image compression format for both loseless and lossy compressions. The input, the renderer, and the output modules from a functional pipeline using MPI for inter-module communication.

ParVox 3.0 has the following new capabilities in comparsion with the previous two releases:

• Addition of a new cell-projection parallel renderer for unstructured grid datasets.
• Addition of perspective rendering for unstructured grid datasets
• Improvement of the GUI program, including:
  • Draw a bounding box in the image window
  • Change the range of the opacity and colormap.

ParVox 1.0 was released in 1998 and it has the following capabilities:

• ParVox runs on the Cray T3D and T3E using SHMEM library.
• Able to render regular structured grid volume data interactively and in batch mode as volume, slices, and iso-surfaces.
• Able to render the multiple time-steps data to create animations.
• Interactive GUI that allows users to manipulate, render, and view the data on local workstations (SGI, Sun, HP, and Linux).
• Colormap and opacity map editing in GUI.
• Supports wavelet image compression, thus allowing ParVox to operate over slower network links.
• Supports multiple output devices: PPM files, lossy compressed images, raw images, and HiPPI framebuffers.

ParVox 2.0 was released in 2000 and it has the following additional capabilities:

• Utilizes MPI communication, so the renderer should run on any platform with MPI support. It has been tested on HP Exemplar, SGI Origin 2000, and Linux Beowulf cluster.
• Pipeline support allows separate input, render, and output modules to run on different processor partitions. The functional pipelining increases the parallel efficiency and allows distributed computing on neterogeneous systems.
• Added out-of-core rendering capability for animation. Now the entire dataset need not be loaded into the renderer at once.
• Improved GUI functions, such as improved animation controls, zooming, and saving/restoring environment settings.

Principal Investigator: P. Peggy Li, Jet Propulsion Laboratory

ParVox was sponsored by the National Aeronautics and Space Administration (NASA) Earth Science Technologies Office (ESTO) Computational Technologies Project (CT). I would like to acknowledge Dr. Scott Whitman and James Tsiao for their contribution to the development of the ParVox system. I would also like to thank Dr. Yi Chao and Dr. Ping Wang of JPL for providing us with the Atlantic Ocean datasets and the 3-D thermal convective dataset, respectively, and Dr. Bob Malone of LANL for providing us with the global ocean model dataset, and Dr. Jay Parker and Dr. Greg Lyzenga for the GeoFEST datasets.

© Copyright 1998 - 2005 California Institute of Technology
ALL RIGHTS RESERVED.
U.S. Government Sponsorship Acknowledged under NAS7-1260

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