[vtkusers] Odd behavior in vtkStreamTracer?

[Bridgman, William T.]

I wish I could isolate the problem for reliable reproduction.  As it  
is, it appears to affect only some of the lines I generate and the  
criteria I have found are not 100% reliable.

One thing that seems to reduce the problem is if I reduce the maximum  
number of steps allowed.  I was using 2500 but the problem is  
significantly reduced when I limit to 1300.  I'll probably try  
dropping it below 1000 to see if that helps also.

Could there be a hard limit on the maximum number of points in  
vtkStreamTracer?  I tried examining some of the vtk code but don't see  
an obvious connection.

Tom
On Feb 12, 2009, at 10:30 PM, Berk Geveci wrote:

> Hi Tom,
>
> Can you share data and maybe a script that demonstrate the problem?
>
> -berk
>
> On Thu, Feb 12, 2009 at 3:28 PM, Bridgman, William T.
> <William.T.Bridgman at nasa.gov> wrote:
>> Hello,
>>
>> I've been generating some field lines using vtkStreamTracer.  The  
>> domain of
>> the field has a hole in the center and I am interested in the flow  
>> into and
>> out of the hole.
>>
>> I've defined my points just outside the spherical hole.  The  
>> northern region
>> has outbound field lines and those are easy.  The southern region has
>> inbound field lines so I set StreamTracer to reverse the direction of
>> propagation.  In the southern case, the lines seem to generate okay  
>> but are
>> actually *two* nearly perfectly overlaid lines with an outbound and  
>> inbound
>> components that seem to have a common node at a position far from  
>> the hole.
>>
>> I've not yet identified a clear pattern in when it does this.  It  
>> does not
>> happen to every field line in the region.
>>
>> I'm using a CVS repository around version 5.2, Linux on 64-bit.
>>
>> Any thoughts?
>>
>> Thanks,
>> Tom
>> --
>> Dr. William T."Tom" Bridgman               Scientific Visualization  
>> Studio
>> Global Science & Technology, Inc.          NASA/Goddard Space  
>> Flight Center
>> Email: William.T.Bridgman at nasa.gov         Code 610.3
>> Phone: 301-286-1346                        Greenbelt, MD 20771
>> FAX:   301-286-1634                        http://svs.gsfc.nasa.gov/
>>
>>
>>
>>
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--
Dr. William T."Tom" Bridgman               Scientific Visualization  
Studio
Global Science & Technology, Inc.          NASA/Goddard Space Flight  
Center
Email: William.T.Bridgman at nasa.gov         Code 610.3
Phone: 301-286-1346                        Greenbelt, MD 20771
FAX:   301-286-1634                        http://svs.gsfc.nasa.gov/