[Paraview] Contours of streamlines crashing

[David Borland]

Thanks Zhanping.

I'm not sure this answers the question of why it is crashing though, as 
it only happens when the streamline output is connected to a contour 
filter, and happens even when generating what appear to be valid 
streamlines.  I also did some testing, and the behavior appears to be 
independent of whether Mask Points or something else (e.g. SphereSource) 
is used for the seed points...

David




On 5/7/2010 1:23 PM, Zhanping Liu wrote:
> Hi David:
>     The streamline integrator sometimes is sensitive to the selection 
> of the initial step size (which is currently kind of large to incur 
> some issues, given a complex dataset particularly containing multiple 
> blocks of irregular boundaries, with some extreme topological 
> structures). Whenever possible, please use RK-45 (which may not 
> necessarily be slower than RK-2, particularly when your dataset is not 
> large) and small values for the step sizes (initial, max) as well as 
> the error threshold.
>     In addition, care needs to be taken when using 'Mask points' 
> to select the seed points. Sometimes many resulting seeds reside 
> exactly on the boundaries between different blocks. In some rare 
> cases, such seeds may cause problems when 'OUT-OF-DOMAIN' status is 
> detected by the integrator.
>     -Zhanping
>
> On Fri, May 7, 2010 at 12:39 PM, David Borland <borland at renci.org 
> <mailto:borland at renci.org>> wrote:
>
>     I have some steady-state vector field data that I am visualizing
>     using streamlines and particles via the following pipeline:
>
>     Mask Points on the input (~100 points) to generate seeds
>     Stream Tracer with Custom Source to generate the streamlines
>     Contour on Integration Time to generate particles, which can then
>     be animated by animating the Isosurface value.
>
>     This was working fine in v3.6.2, but started crashing in v3.8.0.
>      *Note:  The crashing only occurs when the streamline filter
>     output is attached to a contour filter.*  After some
>     investigating, I realized that part of the problem is with
>     different default values for the Stream Tracer in 3.8.0 vs. 3.6.2.
>      From what I have been able to figure out so far, it looks like
>     different values for the Integrator Type (default of Runge-Kutta 2
>     in 3.6.2 and Runge-Kutta 4.5 in 3.8.0) and Initial Step Length
>     (default of 0.5 in 3.6.2 and 0.2 in 3.8.0).  After experimenting
>     with these values, I have found the following:
>
>
>     Windows 3.6.2 64-bit binaries:  Crashes for any Runge-Kutta with
>     Initial Step Size 0.5
>                                                    Works for any
>     Runge-Kutta with Initial Step Size 0.2
>
>     Windows 3.8.0 64-bit binaries:  Crashes for any Runge-Kutta with
>     Initial Step Size 0.5,
>                                                     Hangs for
>     Runge-Kutta 4 and 4.5 with Initial Step Size 0.2
>
>     Ubuntu Linux 3.6.2 64-bit build:  Crashes for any Runge-Kutta with
>     Initial Step Size 0.5,
>                                                       Crashes for
>     Runge-Kutta 4.5 with Initial Step Size 0.2
>
>     Ubuntu Linux 3.8.0 64-bit build:  Crashes for any Runge-Kutta with
>     Initial Step Size 0.5,
>                                                       Crashes for
>     Runge-Kutta 4.5 with Initial Step Size 0.2
>
>
>     The results on Linux seem to be more consistent than on Windows
>     (go figure...), and different data sets on Windows seem to have
>     slightly differnt behavior, but there certainly seems to be some
>     interaction between the initial step size and the integrator type.
>      I'd be happy to log a bug if that is more appropriate than
>     posting to the mailing list.
>
>     David
>
>
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>
>
> -- 
> Zhanping Liu, PhD
> Kitware, Inc.
> 28 Corporate Drive
> Clifton Park, NY 12065-8662
> Phone: 518-371-3971 x 138
> http://www.zhanpingliu.org
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