Scientific Visualization
Building Better Scientific Visualization Capability
By Mark Bolstad
In previous Link articles, the Scientific Visualization Team has described our newest asset, the RAVE display system. For those unfamiliar with the RAVE system, it is a reconfigurable display system consisting of six separate projectors, two each in the center and floor, and one on each of the movable left and right wings. Each of the projectors can display in stereo with a resolution of 1280-by-1024 pixels, with the center and floor regions having a 10 percent overlap of the two projectors. The system also consists of an ultrasonic tracking system and a full 5.1 audio system.
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| One frame from the virtual battlefield, which is used to show ho the ARL MSRC can help warfighters through each of the Computational Technology Areas. |
One of the difficulties with a system like this is using it to its full potential. Several of the software packages available at the MSRC can utilize some portions of the system. For instance, out of the box, EnSight is capable of displaying across all of the displays and using the tracking system for a truly immersive experience. A project was recently undertaken to allow visitors to experience the full capabilities of the RAVE system as well as to provide an overview of how ARL helps the warfighter.
To create this demonstration, the Sci Vis Team created a series of storyboards laying out the sequences and the general outline of the story that was to be told. After several iterations of tuning the storyboards, work commenced on creating the various sequences that would highlight how the ARL MSRC helps the warfighter through the CTAs. A simulated battlefield was developed in the Digital Content Creation (DCC) tool, Houdini. Using Houdini, the Sci Vis Team was able to animate the movement of the various elements, as well as export the distance and direction to each of the elements from the camera. This ability is very important for a reason to be discussed later.
While the battlefield was being developed, a method for displaying the data on the RAVE needed to be created. The Sci Vis Team chose to use Performer, an API from SGI that coordinates the display of images across mulitiple projectors. In addition, the team developed a method to integrate 3D audio into the Performer application. Remember the exported distance and direction information? That data is used to drive the RAVE's 5.1 audio system with sounds for the various elements, such as the helicopters, modulated by distance and location. The team uses NCSA's Virtual Sound Server application to enable this process.
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| Transitioning from the virtual battlefield to the Computational Structural Mechanics sequence. |
For each of the CTA sequences a tie-in from the battlefield animation was created. For example, for the CSM sequence, a transition was developed for the impact of a projectile weapon with a T-72 tank into a CTH calculation that enables a comparison of different materials for a penetrator against a steel plate.
Tying all of the elements together into a seamless demonstration is a time-consuming process, but when graphics, audio, and interaction converge, the insight achieved exceeds what can be realized through the individual parts.