One difficulty with stream arrows is the number of parameters. To generate useful images in a certain situation it is necessary to tune the stream arrows parameters, for instance, scaling factor a for hierarchical stream arrows. To come up with a completely automatic parameter set-up, seems to be a non-trivial problem. Another problem with stream arrows is the number of triangles being handled, when high-quality images are to be generated. Geometric segmentation of stream arrows usually causes many triangles of the original stream surface mesh to be split in even more polygons. Thus, the use of stream arrows within an interactive set-up (e.g., a virtual/augmented environment set-up [26]) might cause performance problems.
It is useful to
sub-structure stream surfaces by the use of texture that is
generated with respect to the underlying flow. Important local
information, e.g., flow direction and velocity, is additionally
integrated in the visualization. Stream arrows are quite useful
to generate high-quality representations
of three-dimensional dynamical systems or flow data.
The cover image of this chapter (see
page ) shows a
visualization, which is quite similar to one of
the expressive images presented by Abraham and
Shaw [1] (see Fig. 4.2).