[CIG-LONG] CIG-LONG Digest, Vol 19, Issue 4

[Thorsten Becker]

Hi Ed,

No clue. I'd mentioned to Berk at Paraview that our tensors are mainly
real and symmetric, and I thought that VTK can deal with that (e.g. by
flipping axes).

Cheers

Thorsten


On Thu, 2008-05-22 at 12:00 -0700, cig-long-request at geodynamics.org
wrote:
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> Today's Topics:
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>    1. Re: Tensors in Paraview (Eh Tan)
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> ----------------------------------------------------------------------
> 
> Message: 1
> Date: Wed, 21 May 2008 13:16:04 -0700
> From: Eh Tan <tan2 at gps.caltech.edu>
> Subject: Re: [CIG-LONG] Tensors in Paraview
> To: cig-short at geodynamics.org,  cig-long at geodynamics.org,
> 	cig-mc at geodynamics.org
> Message-ID: <48348304.3010200 at gps.caltech.edu>
> Content-Type: text/plain; charset=ISO-8859-1
> 
> Thorsten Becker wrote:
> > Dear Paraview (or MayaVi) users within the CIG community:
> >
> > Would it be useful to have the Paraview software implement the VTK
> > Tensor format so that (strain, strain-rate, stress, moment) tensors
> > could be visualized in different ways through glyphs? 
> >   
> 
> 
> Hi Thorsten,
> 
> 
> >From my reading of VTK book (The Visualization Toolkit 3rd ed.), VTK
> tensor can plot a 3D glyph (either 3 axis or an ellipsoid) which orients
> with the eigenvectors of the tensor and scaled with the eigenvalues. It
> seems to me that VTK tensor is designed for positive-definite symmetric
> tensors. How does the glyph scale with a negative eigenvalue? In many
> geophysical problem,  the trace of the tensor is 0, and one of the
> eigenvalues can be negative. Is there a way to distinguish
> positive/negative eigenvalues in VTK tensor?
> 
> 
> 
> Eh
> 
> 
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> End of CIG-LONG Digest, Vol 19, Issue 4
> ***************************************