Efficient Construction of Flow Structures

Visualizing flow structures according to the users’ interests provides insight to scientists and engineers. In previous work, a flow structure based on streamline predicates, that examine, whether a streamline has a given property, was defined. Evaluating all streamlines results in characteristic sets grouping all streamlines with similar behavior with respect to a given predicate. Since there are infinitely many streamlines, the algorithm chooses a finite subset for the computation of an approximated discrete version of the characteristic sets. However, even the construction of characteristic sets based on a finite set of streamlines tends to be computationally expensive. Based on a thorough analysis of all processing steps, we present and compare different acceleration approaches. The techniques are based on simplifications that result in characteristic set boundaries deviating from the correct but computational expensive boundaries. We develop measures for objective comparison of the introduced errors. An adaptive refinement approach turns out to be the best compromise between computation time and quality.