[vtkusers] Oriented Tensor Glyphs

[Jose Paulo Moitinho de Almeida]

Hello

I extended the vtkTensorGlyph class, so that the glyph is repeated and 
oriented at each point, for each eigenvector.

I hope that the result is explained by the examples that are available at 
http://www.civil.ist.utl.pt/~moitinho/vtk

The behaviour of the object is controlled by two new Boolean variables 
ThreeGlyphs and Symmetric. When they are false the object behaves as 
vtkTensorGlyph. 

If ThreeGlyphs is true three glyphs, which are scaled according to the 
eigenvalue along the main axis (the one that after rotation corresponds to 
the eigenvector), are drawn.

If Symmetric is true then the glyph (or the glyphs) is/are mirrored, i.e. 2 or 
6 glyphs are produced.

In the examples both variables are true.

This behaviour is usefull in solid mechanics were other than knowing the 
direction and magnitude of the eigenvectors we also want to know its sign.
Other uses are probably possible...

I tried to write the code according to the instructions (a vtkMy...). Could 
someone who is interested in testing this provide me with some info on the 
best way to "publish" it?


Thank you

Ze Paulo