
 Usage

vtkStreamLine is a filter that generates a streamline for an
arbitrary dataset. 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. Integration can be
performed forward in time (see where the line goes),
backward in time (see where the line came from), or in both
directions. It also is possible to compute vorticity along
the streamline. Vorticity is the projection (i.e., dot
product) of the flow rotation on the velocity vector, i.e.,
the rotation of flow around the streamline.
vtkStreamLine defines the instance variable StepLength. This
parameter controls the time increment used to generate
individual points along the streamline(s). Smaller values
result in more line primitives but smoother streamlines. The
StepLength instance variable is defined in terms of time
(i.e., the distance that the particle travels in the
specified time period). Thus, the line segments will be
smaller in areas of low velocity and larger in regions of
high velocity. (NOTE: This is different than the
IntegrationStepLength defined by the superclass vtkStreamer.
IntegrationStepLength is used to control integration step
size and is expressed as a fraction of the cell length.) The
StepLength instance variable is important because subclasses
of vtkStreamLine (e.g., vtkDashedStreamLine) depend on this
value to build their representation.
To create an instance of class vtkStreamLine, simply invoke
its constructor as follows

    obj = vtkStreamLine



 Methods

The class vtkStreamLine has several methods that can be
used. They are listed below. Note that the documentation is
translated automatically from the VTK sources, and may not
be completely intelligible. When in doubt, consult the VTK
website. In the methods listed below, obj is an instance of
the vtkStreamLine class.

* string = obj.GetClassName ()
* int = obj.IsA (string name)
* vtkStreamLine = obj.NewInstance ()
* vtkStreamLine = obj.SafeDownCast (vtkObject o)
* obj.SetStepLength (double ) - Specify the length of a line
  segment. The length is expressed in terms of elapsed time.
  Smaller values result in smoother appearing streamlines,
  but greater numbers of line primitives.
* double = obj.GetStepLengthMinValue () - Specify the length
  of a line segment. The length is expressed in terms of
  elapsed time. Smaller values result in smoother appearing
  streamlines, but greater numbers of line primitives.
* double = obj.GetStepLengthMaxValue () - Specify the length
  of a line segment. The length is expressed in terms of
  elapsed time. Smaller values result in smoother appearing
  streamlines, but greater numbers of line primitives.
* double = obj.GetStepLength () - Specify the length of a
  line segment. The length is expressed in terms of elapsed
  time. Smaller values result in smoother appearing
  streamlines, but greater numbers of line primitives.


* FreeMat_Documentation
* Visualization_Toolkit_Graphics_Classes
* Generated on Thu Jul 25 2013 17:18:32 for FreeMat by
  doxygen_ 1.8.1.1

