vtkTensorGlyph - scale and orient glyph according to tensor eigenvalues and eigenvectors

Super Class: vtkDataSetToPolyDataFilter

Description:

vtkTensorGlyph is a filter that copies a geometric representation (specified as polygonal data) to every input point. The geometric representation, or glyph, can be scaled and/or rotated according to the tensor at the input point. Scaling and rotation is controlled by the eigenvalues/eigenvectors of the tensor as follows. For each tensor, the eigenvalues (and associated eigenvectors) are sorted to determine the major, medium, and minor eigenvalues/eigenvectors. The major eigenvalue scales the glyph in the x-direction, the medium in the y-direction, and the minor in the z-direction. Then, the glyph is rotated so that the glyph's local x-axis lies along the major eigenvector, y-axis along the medium eigenvector, and z-axis along the minor. A scale factor is provided to control the amount of scaling. Also, you can turn off scaling completely if desired. The boolean variable ClampScaling controls the maximum scaling (in conjunction with MaxScaleFactor.) This is useful in certain applications where singularities or large order of magnitude differences exist in the eigenvalues. Another instance variable, ExtractEigenvalues, has been provided to control extraction of eigenvalues/eigenvectors. If this boolean is false, then eigenvalues/eigenvectors are not extracted, and the columns of the tensor are taken as the eigenvectors (norm of column is eigenvalue). This allows additional capability over the vtkGlyph3D object. That is, the glyph can be oriented in three directions instead of one.

See Also:

vtkGlyph3D vtkPointLoad vtkHyperStreamline

Methods:

Detailed Method Descriptions: