Documentation for vtkHyperStreamline

vtkHyperStreamline - generate hyperstreamline in arbitrary dataset

Description:

vtkHyperStreamline is a filter that integrates through a tensor field to generate a hyperstreamline. The integration is along the maximum eigenvector and the cross section of the hyperstreamline is defined by the two other eigenvectors. Thus the shape of the hyperstreamline is "tube-like", with the cross section being elliptical. Hyperstreamlines are used to visualize tensor fields. The starting point of a hyperstreamline can be defined in one of two ways. First, you may specify an initial position. This is a x-y-z global coordinate. The second option is to specify a starting location. This is cellId, subId, and cell parametric coordinates. The integration of the hyperstreamline occurs through the major eigenvector field. IntegrationStepLength controls the step length within each cell (i.e., this is the fraction of the cell length). The length of the hyperstreamline is controlled by MaximumPropagationDistance. This parameter is the length of the hyperstreamline in units of distance. The tube itself is composed of many small sub-tubes - NumberOfSides controls the number of sides in the tube, and StepLength controls the length of the sub-tubes. Because hyperstreamlines are often created near regions of singularities, it is possible to control the scaling of the tube cross section by using a logarithmic scale. Use LogScalingOn to turn this capability on. The Radius value controls the initial radius of the tube.

See Also:

vtkTensorGlyph vtkStreamer

Methods:

	void vtkHyperStreamline ()
	void vtkHyperStreamline ()
	const char *GetClassName ()
	void PrintSelf (unknown & ,vtkIndent )
	static vtkHyperStreamline *New ()
	void SetStartLocation (int ,int ,float )
	void SetStartLocation (int ,int ,float ,float ,float )
	int GetStartLocation (int & ,float )
	void SetStartPosition (float )
	void SetStartPosition (float ,float ,float )
	float *GetStartPosition ()
	void SetMaximumPropagationDistance (float )
	float GetMaximumPropagationDistance ()
	void IntegrateMajorEigenvector ()
	void IntegrateMediumEigenvector ()
	void IntegrateMinorEigenvector ()
	void SetIntegrationStepLength (float )
	float GetIntegrationStepLength ()
	void SetStepLength (float )
	float GetStepLength ()
	void SetIntegrationDirection (int )
	int GetIntegrationDirection ()
	void SetIntegrationDirectionToForward ()
	void SetIntegrationDirectionToBackward ()
	void SetIntegrationDirectionToIntegrateBothDirections ()
	void SetTerminalEigenvalue (float )
	float GetTerminalEigenvalue ()
	void SetNumberOfSides (int )
	int GetNumberOfSides ()
	void SetRadius (float )
	float GetRadius ()
	void SetLogScaling (int )
	int GetLogScaling ()
	void LogScalingOn ()
	void LogScalingOff ()
	void Execute ()
	void BuildTube ()

Detailed Method Descriptions:

Construct object with initial starting position (0,0,0); integration step length 0.2; step length 0.01; forward integration; terminal eigenvalue 0.0; number of sides 6; radius 0.5; and logarithmic scaling off.

static vtkHyperStreamline *New ()

Specify the start of the hyperstreamline in the cell coordinate system. That is, cellId and subId (if composite cell), and parametric coordinates.

	void SetStartLocation (int ,int ,float )
	void SetStartLocation (int ,int ,float ,float ,float )

Get the starting location of the hyperstreamline in the cell coordinate system. Returns the cell that the starting point is in.

int GetStartLocation (int & ,float )

Specify the start of the hyperstreamline in the global coordinate system. Starting from position implies that a search must be performed to find initial cell to start integration from.

	void SetStartPosition (float )
	void SetStartPosition (float ,float ,float )

Get the start position of the hyperstreamline in global x-y-z coordinates.

float *GetStartPosition ()

Set / get the maximum length of the hyperstreamline expressed as absolute distance (i.e., arc length) value.

	void SetMaximumPropagationDistance (float )
	float GetMaximumPropagationDistance ()

Use the major eigenvector field as the vector field through which to integrate. The major eigenvector is the eigenvector whose corresponding eigenvalue is closest to positive infinity.

void IntegrateMajorEigenvector ()

Use the major eigenvector field as the vector field through which to integrate. The major eigenvector is the eigenvector whose corresponding eigenvalue is between the major and minor eigenvalues.

void IntegrateMediumEigenvector ()

Use the major eigenvector field as the vector field through which to integrate. The major eigenvector is the eigenvector whose corresponding eigenvalue is closest to negative infinity.

void IntegrateMinorEigenvector ()

Set / get a nominal integration step size (expressed as a fraction of the size of each cell).

	void SetIntegrationStepLength (float )
	float GetIntegrationStepLength ()

Set / get the length of a tube segment composing the hyperstreamline. The length is specified as a fraction of the diagonal length of the input bounding box.

	void SetStepLength (float )
	float GetStepLength ()

Specify the direction in which to integrate the hyperstreamline.

	void SetIntegrationDirection (int )
	int GetIntegrationDirection ()
	void SetIntegrationDirectionToForward ()
	void SetIntegrationDirectionToBackward ()
	void SetIntegrationDirectionToIntegrateBothDirections ()

Set/get terminal eigenvalue. If major eigenvalue falls below this value, hyperstreamline terminates propagation.

	void SetTerminalEigenvalue (float )
	float GetTerminalEigenvalue ()

Set / get the number of sides for the hyperstreamlines. At a minimum, number of sides is 3.

	void SetNumberOfSides (int )
	int GetNumberOfSides ()

Set / get the initial tube radius. This is the maximum "elliptical" radius at the beginning of the tube. Radius varies based on ratio of eigenvalues. Note that tube section is actually elliptical and may become a point or line in cross section in some cases.

	void SetRadius (float )
	float GetRadius ()

Turn on/off logarithmic scaling. If scaling is on, the log base 10 of the computed eigenvalues are used to scale the cross section radii.

	void SetLogScaling (int )
	int GetLogScaling ()
	void LogScalingOn ()
	void LogScalingOff ()