Re: [vmtk-users] vtkvmtkPolyDataCenterlines class warning

[Luca A. <luc...@gm...>]

Hi Eleni,
  I understand. Probably what happens is that you're working on a  
surface that has open endcaps (is it the case?), which leads to a  
Voronoi diagram that exits the inside of the vessel through the  
endcaps (hence the centerlines outside the domain).
You may consider using vtkvmtkCapPolyData to cap it, and then specify

centerlineFilter->SetCapCenterIds(capPolyDataFilter->GetCapCenterIds());

This may solve your problem, let me know.


Luca


On Mar 29, 2010, at 12:37 AM, Sgouritsa, Eleni wrote:

> Hi Luca,
>
> thank you very much for your help. However, I don't use the  
> vmtkcenterlines script but just the vtkvmtkPolyDataCenterlines class  
> (same as with itk and vtk) as follows:
>
> // compute centerline
> vtkSmartPointer<vtkvmtkPolyDataCenterlines> centerlineFilter =  
> vtkSmartPointer<vtkvmtkPolyDataCenterlines>::New();
> centerlineFilter->SetInput(VesselMesh);
> centerlineFilter->SetSourceSeedIds(pIdSources);
> centerlineFilter->SetTargetSeedIds(pIdTargets);
> centerlineFilter->SetRadiusArrayName("Vessel Radii");
> centerlineFilter->Update();
> Centerline=centerlineFilter->GetOutput();
>
> Is there a way to do the usetetgen 1 without using the script?
>
> I get two type of warnings:
> - Warning 1: "Generic Warning: In ..\..\vtk-5.4.0\Common 
> \vtkMath.cxx, line 544
> Unable to factor linear system"
> - Warning 2: "Warning: In ..\..\vtk-5.4.0\CGraphics 
> \vtkDelaunay3D.cxx, line 487
> vtkDelaunay3D (0220EF58): x degenerate triangles encountered, mesh  
> quality suspect"
>
> I attach three images with the only three datasets that had some  
> problem.
> - Image "WarningCorrectCenterline.jpg" seems to produce a correct  
> centerline
> - Image "WarningCorrectCenterline.jpg" produces a wrong centerline  
> outside the vessel
> - Image ""WarningProgramCrashesNoCenterline.jpg" gives the warning  
> "Warning: In ..\..\vtk-5.4.0\CGraphics\vtkDelaunay3D.cxx, line 487
> vtkDelaunay3D (0220EF58): 3 degenerate triangles encountered, mesh  
> quality suspect" and crashes without giving a centerline
>
>
> Best regards,
> Eleni
>
>
>
> -----Original Message-----
> From: Luca Antiga [mailto:luc...@gm...]
> Sent: Sat 3/27/2010 4:36 PM
> To: Sgouritsa, Eleni
> Cc: vmt...@li...
> Subject: Re: [vmtk-users] vtkvmtkPolyDataCenterlines class warning
>
> Dear Eleni,
>   as a try (no guarantees), you can add
> -usetetgen 1
> to the options of vmtkcenterlines and see if centerlines come out  
> right.
> You probably have some very regular geometric configurations of points
> somewhere on your surface, and VTK's Delaunay algorithm suffers from
> the lack of arbitrary precision. tetgen has it, so it may solve the
> problem.
>
> If you want, feel free to post a screenshot of your surface, just to
> have an idea on what kind of geometry you're dealing with and to what
> degree centerlines are wrong.
>
> Best regards
>
> Luca
>
>
> On Mar 24, 2010, at 8:14 PM, Sgouritsa, Eleni wrote:
>
> > Hello,
> >
> > I am using vtkvmtkPolyDataCenterlines class (vmtk 0.8) to extract
> > the centerlines of the vessels in my dataset. Almost for all the 20
> > vessels the algorithm works fine. However in case of 2 or 3 vessels
> > I get several times the following  warning:
> > "Generic Warning: In ..\..\vtk-5.4.0\Common\vtkMath.cxx, line 544
> > Unable to factor linear system"
> >
> > which results in a completely wrong centerline outside the vessel or
> > to the crash of my program.
> >
> > Is there something I can do for that?
> >
> > Thank you in advance.
> >
> > Eleni
> >
> >  
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>
>
>
>
> < 
> WarningCorrectCenterline 
> .jpg 
> ><WarningWrongCenterline.jpg><WarningProgramCrashesNoCenterline.jpg>