Scientific visualization is both a key ingredient for the understanding of complex physical phenomena and an unsurpassed means for presenting and communicating information about quantifiable properties. Most of these properties (like spatial coordinates), although of continuous nature, are discretized for the purpose of numerical treatment or due to discrete measurements. The engineering discipline and art to create enlighting and eye-pleasing pictures from discrete data are able to fill several Ph.D. theses.
In the past years, the field of scientific visualization has received considerable beneficial stimulation from visualization problems and techniques in related fields such as medicine, meteorology, geosciences, image processing, flight simulation, graphical user interfaces, or video animation and an end of this ongoing development is definitely not in sight. One of the most dramatic and valuable achievements in scientific visualization, as far as device and process simulation is concerned, seem to be volume visualization techniques. This is the direct (in contrast to the indirect, classical ``Cutting, Slicing, Clipping'' approach [89] that extracts intermediate surface representations) visualization of volumetric data [90] [91].
Besides the progress in these leading-edge areas, as with any other technical or scientific Computer-Aided discipline, the practical progress and focus is shifting towards integrative aspects. Open systems, standards, interfaces, and toolkit concepts are becoming more important than singular sophisticated features. An overview of existing general-purpose visualization systems is given, e.g., in [92].
VISTA's visualization emphasizes the integrative aspect and follows an open toolkit approach. The utmost simple approach consists of a generic data backbone and just enough modular functionality to meet the most important TCAD-related visualization demands. Instead of making direct use of the many platforms and interfaces for computer graphics provided by different vendors and consortia (thereby indeed re-using existing standards and products, but, most unfortunately, submitting a vital part of VISTA to an untolerable dependence upon proven subjects of uncontrollable evolution) VISTA defines a limited and comprehensive visualization concept with a minimum set of built-in functionality, which is also capable to accommodate unidirectional interfaces to visualization systems on different levels of abstraction and sophistication.
In the remaining sections, the architecture and some implementation aspects of the VISTA visualization toolkit are described, two advanced modules for volume visualization and flow-line extraction are presented, and a concluding discussion section summarizes important observations and gives some clues for future developments.