[CIG-SHORT] Fault-slip vector plot

[Charles Williams]

Attached is a simple Python script to compute principal axes, along with the associated .cfg file.  You will need to edit the .cfg file for your particular problem.  Let me know if this works OK for you -- I haven't really tested it.  If I'm remembering correctly, you will end up with one vector for each principal axis direction, which will allow you to plot each principal axis separately as a glyph.

Charles



On 12/04/2011, at 4:47 AM, Brad Aagaard wrote:

> On 04/11/2011 09:01 AM, luigi vadacca wrote:
>> Dear all,
>> 
>> I have two questions about the plot of the fault slip vector and principal
>> stress axes in paraview.
>> 
>> In figure 7.33 of the example "step11" of the pylith manual is written:
>> 
>> "Note that PyLith outputs slip in the fault coordinate system, so we transform
>> them to the global coordinate
>> system using the Calculator in ParaView. A more general approach involves
>> outputing the fault coordinate
>> system information and using these fields in the Calculator"
>> 
>> 1 - How can I do this?
> 
> For the fault output, request that the output include the strike, dip, 
> and normal directions in the info file using something similar to the 
> following (you may need to adjust the name of the fault output component 
> if you have more than one fault or name your fault component something 
> else; you may also want to add other info fields to the output such as 
> final slip and slip time):
> 
> [pylithapp.timedependent.interfaces.fault.output]
> vertex_info_fields = [strike_dir,dip_dir,normal_dir]
> 
> In ParaView you can use the calculator to take the dot product of the 
> slip with the three directions to get the slip vector in global 
> coordinates. For example,
> 
> (slip[0]*strike_dir[0] +
>  slip[1]*dip_dir[0] +
>  slip[2]*normal_dir[0]) * iHat +
> (slip[0]*strike_dir[1] +
>  slip[1]*dip_dir[1] +
>  slip[2]*normal_dir[1]) * jHat +
> (slip[0]*strike_dir[2] +
>  slip[1]*dip_dir[2] +
>  slip[2]*normal_dir[2]) * kHat
> 
>> 
>> 2 - Is possible to plot the three principal stress axes directly in paraview?
> 
> ParaView does not supply a filter to calculate the principal stresses, 
> so you will need to write your own post-processing script.
> 
> 
> Brad
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Charles A. Williams
Scientist
GNS Science
1 Fairway Drive, Avalon
PO Box 30368
Lower Hutt  5040
New Zealand
ph (office): 0064-4570-4566
fax (office): 0064-4570-4600
C.Williams at gns.cri.nz

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