83rd Annual

Tuesday, 11 February 2003: 9:00 AM
Serving 3-D rendered graphics of ocean model output using LAS and VTK
Albert J. Hermann, JISAO/Univ. of Washington, Seattle, WA; and C. W. Moore and E. L. Dobbins
Poster PDF (464.3 kB)
Scientists at NOAA's PMEL laboratory are relying more and more on supercomputing platforms for their modeling efforts. Running ocean models on these large cluster machines poses problems in that domain sizes are increasing and tracking how the model dynamics are developing during a run requires high-bandwidth network time. In an effort to streamline this procedure both server and 3-D rending technology are utilized.

Intermediate model results saved in netCDF file format can be served remotely to query model progress using the Live Access Server (LAS), and bandwidth can be saved by using a back-end application to serve 3-D rendered geometry in the form of VRML over the web. In our implementation, a crontab script checks for model results and generates an XML data-file descriptor and adds the data set to the list of those available for LAS to serve up. On top of the default product choices (2-D plots, data listings, etc), the user can also chose a VRML isosurface of the variable of interest. LAS then invokes a Visualization Toolkit (VTK) application whose input includes the variable name, region of interest, and netCDF file, and creates a VRML file of the isosurface (as well as topography and surface current vectors). File size can be controlled through the use of topology-preserving polygon mesh decimation algorithms. Animations of the isosurface are obtained through the use of an external prototype node and javascript. Results can be viewed in stereo locally through the use of a VRML-aware internet browser and an inexpensive stereo-capable video card.

A description of the technique can be found at www.pmel.noaa.gov/~hermann, and a demonstration of the is available on-line at http://elegua.pmel.noaa.gov/las.

Supplementary URL: http://www.pmel.noaa.gov/vrml/las