Stream Tracer (StreamTracer)
Integrate streamlines in a vector field.
The Stream Tracer filter generates streamlines in a vector field from a collection of seed points. Production of streamlines terminates if a streamline crosses the exterior boundary of the input dataset. Other reasons for termination are listed for the MaximumNumberOfSteps, TerminalSpeed, and MaximumPropagation properties. This filter operates on any type of dataset, provided it has point-centered vectors. The output is polygonal data containing polylines.

PropertyDescriptionDefault Value(s)Restrictions
Initial Step Length
(InitialIntegrationStep)
The value of this property specifies the initial integration step. For non-adaptive integrators, Runge-Kutta 2 and 4, the initial step size is used throughout the integration. 0.5  
Initial Step Unit
(InitialIntegrationStepUnit)
This property indicates the unit for specifying the initial integration step. The Time (0) and Length (1) units have the same meaning as that specified in the MaximumPropagationUnit property. The Cell Length (2) unit specifies the step length as a number of cells. 2

The value must be one of the following: Time (0), Length (1), Cell Length (2).

 
Input
(Input)
This property specifies the input to the Stream Tracer filter.  

The selected object must be the result of the following: sources (includes readers), filters.

The dataset must contain a point array with 3 components.

The selected dataset must be one of the following types (or a subclass of one of them): vtkDataSet.

 
Integration Direction
(IntegrationDirection)
This property determines in which direction(s) the stream trace will be generated. 2

The value must be one of the following: FORWARD (0), BACKWARD (1), BOTH (2).

 
Integrator Type
(IntegratorType)
This property determines which calculation to use for integration. 0

The value must be one of the following: Runge-Kutta 2 (0), Runge-Kutta 4 (1), Runge-Kutta 4-5 (2).

 
Maximum Error
(MaximumError)
This property specifies the maximum error allowed in the integration. The meaning of this value depends on the integrator chosen. The Runge-Kutta 4-5 integrator tries to choose the step size so that the estimated error is less than the value of this property. 1e-06  
Maximum Step Length
(MaximumIntegrationStep)
If using the Runge-Kutta 4-5 ingrator (IntegratorType property), this property specifies the minimum integration step. 0.01  
Maximum Step Unit
(MaximumIntegrationStepUnit)
If the Runge-Kutta 4-5 integrator is selected (IntegratorType property), this property determines the unit to use for specifying the maximum integration step. Time (0), Length (1), and Cell Length (2) have the same meanings as those indicated for the InitialIntegrationStepUnit property. 2

The value must be one of the following: Time (0), Length (1), Cell Length (2).

 
Max. Steps
(MaximumNumberOfSteps)
If the integration takes more steps to complete than indicated by this property, the integration terminates. 2000  
Max. Propagation
(MaximumPropagation)
The value of this property specifies the maximum streamline length. If the streamline length goes beyond this value, integration of that strealine terminates. 1

The value must be less than the largest dimension of the dataset multiplied by a scale factor of 1.

 
Max. Propagation Unit
(MaximumPropagationUnit)
This property indicates the unit for specifying the maximum streamline length. The Time (0) unit is the time a particle would travel with steady flow. The Length (1) unit is specified in the dataset's spatial coordinates. 1

The value must be one of the following: Time (0), Length (1).

 
Minimum Step Length
(MinimumIntegrationStep)
If using the Runge-Kutta 4-5 ingrator (IntegratorType property), this property specifies the minimum integration step. 0.01  
Minimum Step Unit
(MinimumIntegrationStepUnit)
If the Runge-Kutta 4-5 integrator is selected (IntegratorType property), this property determines the unit to use for specifying the minimum integration step. Time (0), Length (1), and Cell Length (2) have the same meanings as those indicated for the InitialIntegrationStepUnit property. 2

The value must be one of the following: Time (0), Length (1), Cell Length (2).

 
Vectors
(SelectInputVectors)
This property contains the name of the vector array from which to generate streamlines.  

An array of vectors is required.

 
Seed Type
(Source)
The value of this property determines how the seeds for the streamlines will be generated.  

The selected object must be the result of the following: sources (includes readers).

The value must be set to one of the following: PointSource, LineSource.

 
Term. Speed
(TerminalSpeed)
If at any point the speed is below the value of this property, the integration is terminated. 1e-12