Interactive Volume Visualization of Complex Flow Semantics.
Helwig Hauser, Matej Mlejnek · 2003
Figure 1: Volume visualization representing a user’s interest in a back-flow region and vortical structures (left side, more details in section 6.1) and in the in-flow of hot fluid in an extended T-junction (right side, more details in section 6.2). Volume rendering (back-flow region, left, and not-hot high pressure areas, and the right), a gradient-dependent iso-surface (316 K, right), and interest-dependent streamlines are used. Comprehending results from 3D CFD simulation is a difficult task. In this paper, we present a semantics-based approach to featurebased volume rendering of 3D flow data. We make use of interactive feature specification to acquire derived data about what is most interesting to the user. This process results in so-called degree-ofinterest (DOI) values, associated with the original data items. This information is then used during the visualization mapping to allow for visualization of flow semantics. We present three different approaches in this paper: (a) isosurfacing the degree of interest – the result is a triplet (or quintuplet) of iso-surfaces representing levels of interest; (b) feature volumes – volume rendering is used to depict 3D distributions of DOI values; and (c) interest-based seeding of streamlines, resulting in reduced clutter while focusing on the most interesting parts of the 3D flow. We utilize fast volume rendering (RTVR) for real-time viewing, also providing two-level volume rendering, which allows to seamlessly integrate all of the above-mentioned approaches.