To overcome Movie's limitations we developed a multi-dimensional visualization application running on SEP's CM-5 and based on the AVS (Application Visualization System) graphics system. We chose the CM-5 as the developing platform because of its data-handling capabilities. In particular, the CM-5 provides fast I/O for reading the data from files on disks that can span multiple gigabytes and it has up to one gigabyte of memory to store large subsets of the survey. In addition, the multiple data-paths to memory that are typical of a parallel computer allow fast access to data stored in memory according to a wide variety of data-access patterns. Finally, the processing capabilities of the CM-5 allow the user to perform some simple image processing (i.e. clipping and gaining) in an interactive fashion, improving the information content of the display.
We developed the visualizer using AVS and CM/AVS (an adaptation of AVS to the CM-5 developed by Thinking Machines) mainly for two reasons. First, AVS enabled us to quickly develop modular interactive applications. More importantly, AVS allows the visualization of many different types of geophysical data integrated in the same display. For example, our data-slicer can be integrated with a geological model (e.g. GOCAD Mallet (1993)) and velocity model visualizer. The final goal is to make available to SEP researchers a fully integrated tool for understanding 3-D seismic data and its relationship with geological and velocity models.
The visualization application that we have developed has some limitations. Some of them are intrinsic to the design, and thus it would be difficult to remove them without overhauling the whole application. The most important restriction is that the data to be visualized must be in SEP format, i.e. it must be regularly sampled along all the axes. This restriction does not necessarily limit the handling of marine surveys, but it is definitely a problem for land data. As for performance, presently the bottleneck is the in last step of the visualization process. Once images are extracted from the data and processed on the CM-5, they need be sent to an X-server. The efficiency of this communication step should improve with future developments of the CM-5 software and hardware, but it is presently unsatisfactory.