Abstract
Comprehending results from 3D CFD simulation is a difficult task. In this paper, we present a semantics-based approach to feature-based volume rendering of 3D flow data. We make use of interactive feature specification to acquire so-called degree-of-interest (DOI) values, which describe what is most interesting to the user (at a current point in time). We adapt three visualization techniques to achieve better visualization answers to specific user questions: (a) isosurfacing the degree of interest - gradient-dependent semi -transparency of isosurfaces is used and a triplet of isosurfaces represents certain levels of interests (b) feature volumes - volume rendering is used to depict 3D distributions of DOI values, and (c) interest-based seeding of streamlines, resulting in streamlines which are automatically placed in regions of special interest. We utilize HW-accelerated resampling and fast shear-warp volume rendering (RTVR) for real-time viewing, also providing two-level volume rendering, which allows to integrate all of the above-mentioned approaches.