[CIG-SHORT] Fault-slip vector plot

[Brad Aagaard]

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