A streamline is a line that is everywhere tangent to the vector field. Scalar values also are calculated along the streamline and can be used to color the line. Streamlines are calculated by integrating from a starting point through the vector field. It also is possible to compute vorticity along the streamline. This parameter controls the length of the line segments used to define the streamline.
Smaller values reduce in more line primitives but smoother streamlines.
Thus, the line segments will be smaller in areas of low velocity and larger in regions of high velocity. This is different than the IntegrationStepLength defined by the superclass vtkStreamer . The length is expressed in terms of elapsed time. Smaller values result in smoother appearing streamlines, but greater numbers of line primitives.