vtkStreamer

Section: Visualization Toolkit Graphics Classes

Usage

vtkStreamer is a filter that integrates a massless particle through a vector field. The integration is performed using second order Runge-Kutta method. vtkStreamer often serves as a base class for other classes that perform numerical integration through a vector field (e.g., vtkStreamLine).

Note that vtkStreamer can integrate both forward and backward in time, or in both directions. The length of the streamer is controlled by specifying an elapsed time. (The elapsed time is the time each particle travels.) Otherwise, the integration terminates after exiting the dataset or if the particle speed is reduced to a value less than the terminal speed.

vtkStreamer integrates through any type of dataset. As a result, if the dataset contains 2D cells such as polygons or triangles, the integration is constrained to lie on the surface defined by the 2D cells.

The starting point of streamers may be defined in three different ways. Starting from global x-y-z "position" allows you to start a single streamer at a specified x-y-z coordinate. Starting from "location" allows you to start at a specified cell, subId, and parametric coordinate. Finally, you may specify a source object to start multiple streamers. If you start streamers using a source object, for each point in the source that is inside the dataset a streamer is created.

vtkStreamer implements the integration process in the Integrate() method. Because vtkStreamer does not implement the Execute() method that its superclass (i.e., Filter) requires, it is an abstract class. Its subclasses implement the execute method and use the Integrate() method, and then build their own representation of the integration path (i.e., lines, dashed lines, points, etc.).

To create an instance of class vtkStreamer, simply invoke its constructor as follows

  obj = vtkStreamer

Methods

The class vtkStreamer 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 vtkStreamer class.