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CGNS Steering Committee

Telecon Minutes

25 October 2000
2:00pm Eastern Time

The meeting was called to order at 2:00 Eastern time. There were 14 attendees, listed below.

The minutes of the 24 August meeting were reviewed and approved as posted on the web site.

The January meeting is tenatively scheduled for Monday night at Reno.


   Bob Bush   UTRC
Chris Rumsey NASA Langley
Dave Schowalter Fluent
Don Roberts Ametec
Ed Ascoli (for Armen Darian) Boeing
Charlie Towne NASA Glenn
Dan Dominik Boeing
Diane Poirier ICEM CFD Engineering
Francis Enomoto NASA Ames
David Edwards Intelligent Light
Doug McCarthy Boeing Commercial
Todd Michal Boeing Phantom Works
Michel Delanaye Numeca
Kevin Mack Adapco

Aerospace America Article

Interactive Computer Graphics

Outstanding developments in Y2K included: collaborative systems for better utilization of graphics hardware, co-processing systems for visualizing large-scale simulations, an emerging ISO standard for CFD data exchange, and commercialization of automatic feature extraction tools.

Many aerospace companies and government laboratories have established Visualization Lab's that contain specialized SGI graphics workstations to generate hi-resolution computer graphics images. These labs have been poorly utilized in the past because engineers often had to travel great distances to use the graphics hardware. This situation is rapidly changing as vendors adapt their software to utilize the Internet and corporate intranets. For example, EnLiten is a new product from Computational Engineering International (CEI) that allows high-end visualizations to be easily and cost-effectively shared throughout an enterprise. EnLiten supports 3D stereo viewing and a full range of computing and display systems, from notebook computers to workstations to semi-immersive environments such as the NCSA ImmersaDesk. It plugs into well-known browsers and viewers such as MS Internet Explorer, MS PowerPoint, and Netscape.

Parallel computing is rapidly emerging as the method of choice for visualizing large-scale CFD solutions. Intelligent Light has built upon MIT's pV3 client-server infrastructure with the popular Fieldview software. The result is a fully supported, robust commercial "graphics client" for the pV3 system. pV3 is used throughout the world for visualization co-processing, that is, concurrent simulation and interactive visualization. Intelligent Light's implementation supports systems ranging from laptop Windows PC's through UNIX clusters and supercomputers and enables enterprise-wide visualization.

Every CFD code that enters the marketplace generates datasets with a slightly different format than their competitor. Products that utilize these datasets, i.e., pre- and post-processing software, have to support approximately 50 different file formats at the present time. The lack of standardization forces vendors to spend an inordinate amount of time implementing and maintaining file exchange software. To combat this software crisis, a consortium of CFD users and vendors have adopted a formal standard for exchanging CFD data called the CFD General Notation System (CGNS). The CGNS system facilitates the exchange of data between sites and applications, and stabilizes the archiving of aerodynamic data. An Application Program Interface, implemented by ICEM CFD Engineering, is platform independent and simplifies the installation of CGNS in C, C++, and Fortran applications. CGNS was conceived back in 1994 as a means to promote "plug-and-play" CFD via a file specification standard and supporting code that could be distributed freely. In 2000, the CGNS Steering Committee affiliated with AIAA as a subcommittee, made progress in proposing CGNS as an ISO standard, and added capabilities to the standard to handle increasingly specialized and complex meshes. Currently, there are over 20 CFD applications that support or have translators for CGNS. Further information about this effort can be found at

Automatic feature extraction tools have transitioned from research institutions to commercial vendors of post-processing software in the past six months. The open-source FX (Feature eXtraction) library released by MIT in June 2000, has been adopted by two leading suppliers of CFD visualization software; Intelligent Light (Fieldview) and CEI (Ensight). Feature extraction tools automatically deduce the location, shape, and strength of specific features without human intervention, and do so in substantially less time than their human counterpart. This is a different paradigm than typical graphical analysis methods where the engineer has to do the work, interpreting the data from imagery and using their insight or experience to infer and find specific patterns. Feature extraction algorithms are programmed with domain-specific knowledge, so they do not require a-priori knowledge of places to look for interesting behavior. The latest feature extraction tools, developed at MIT and NASA Ames, automatically calculate vortex cores, separation and re-attachment lines, and shock surfaces. These tools will be available in Fieldview 7 and Ensight Gold in the final quarter of Y2K.

David Kenwright
Figure 1 [sh_side35.jpg] (to be supplied by CEI)
Figure 2 [f16.jpg] An F16 solution from the USAF Cobalt group. Vortex cores are colored by strength and were used to guide the creation of streamlines. (Image courtesy of Intelligent Light)

Dr. David N. Kenwright
Principal Research Scientist
Department of Aeronautics and Astronautics
Massachusetts Institute of Technology
Bldg 37-462, 77 Vassar Street
Cambridge, MA 02139

Tel. (617) 253-3505
Fax. (617) 258-5143