[Insight-users] Deleting a point from a Quad Edge mesh

[Mahnaz Maddah]

Hi Alex,

      yes! it does work perfectly fine now.

thanks,
-Mahnaz


On 08/30/2010 02:09 AM, Alexandre GOUAILLARD wrote:
> hi manhaz,
>
> can you try this patch (git-am) ? That should do the trick.
>
> alex.
>
>
> On Wed, Aug 25, 2010 at 1:56 AM, Mahnaz Maddah<mmaddah at synapse.sri.com>  wrote:
>>   Thanks Alex. It partly worked. Seems when you delete a point from the mesh,
>> its associated data does not get deleted automatically. So when in my vtk
>> writer I call the GetPointData(idx,&pointvalue), it returns data from the
>> old point id sequence not the modified one. Should a similar Squeeze
>> function be applied to the point data container?
>>
>> QuadEdgeMeshType::PointsContainer::Pointer points = mesh->GetPoints();
>> for(QuadEdgeMeshType::PointsContainer::Iterator i = points->Begin(); i !=
>>       points->End(); ++i)
>>     {
>>       int idx = i->Index();
>> ...
>>       mesh->GetPointData(idx,&pointvalue);
>> ...
>>
>>
>> Thanks,
>> -Mahnaz
>>
>> On 08/24/2010 12:30 AM, Alexandre GOUAILLARD wrote:
>>> hi mahnaz,
>>>
>>> the vtk file writer supposes a point list whose IDs are incremental
>>> (point Ids are implicit in vtk, whereas points Ids are explicit in
>>> ITK). As soon as you delete a point, you create a gap in the IDs. To
>>> make it easier to use the writer, I implemented a mechanism in ITK
>>> that keep track of deleted points and can "squeeze" the point list so
>>> that the Ids are sequential:
>>>
>>> Its doxygen documentation is here:
>>>
>>> http://www.itk.org/Doxygen318/html/classitk_1_1QuadEdgeMesh.html#ae3b55e8ed3beb3dffb91933245a79906
>>> "
>>> void itk::QuadEdgeMesh<    TPixel, VDimension, TTraits>::SqueezePointsIds ()
>>>
>>> squeeze the point container to be able to write the file properly
>>> "
>>>
>>> just call SqueezePointsIds() before you write the mesh, and you should be
>>> fine.
>>>
>>> alex.
>>>
>>>
>>>
>>> On Tue, Aug 24, 2010 at 4:45 AM, Mahnaz Maddah<mmaddah at synapse.sri.com>
>>>   wrote:
>>>> I've been trying to delete a point that has invalid point data associated
>>>> with it from its belonging QuadEdge mesh.
>>>>
>>>> Comparing the values printed out for point and pointToBeDeleted in my
>>>> code
>>>> below, it seems the right point (vertex) is being deleted, however as
>>>> soon
>>>> as only one point is deleted from the mesh, my vtk polydata writer does
>>>> not
>>>> work for the modified mesh (it works well if no point gets deleted).
>>>>
>>>> Could someone please verify if the following code is the right way to
>>>> delete
>>>> a point and also what happens to the data associated with the deleted
>>>> point?
>>>>
>>>> Thanks,
>>>> -Mahnaz
>>>>
>>>>
>>>>
>>>>
>>>> typedef
>>>> itk::QuadEdgeMeshEulerOperatorJoinVertexFunction<QuadEdgeMeshType,
>>>> QuadEdgeMeshType::QEType>    jointFunctionType;
>>>> jointFunctionType::Pointer joinVertex=jointFunctionType::New();
>>>>
>>>>     unsigned int j=0;
>>>>     while  (j<    mesh->GetNumberOfPoints())
>>>>       {
>>>>         mesh->GetPoint(j,&point);
>>>>         mesh->GetPointData(j,&pointvalue);
>>>>         if (pointvalue.FA ==nanVal)
>>>>         {
>>>>             //std::cout<<    j<<    "     "<<    point[0]<<""<<    point[1]<<    "
>>>> "<<    point[2]<<    std::endl;
>>>>             joinVertex->SetInput(mesh);
>>>>             if (joinVertex->Evaluate(mesh->FindEdge(j)))
>>>>            {
>>>>                 int pid = joinVertex->GetOldPointID();
>>>>                 QuadEdgeMeshType::PointType pointToBeDeleted =
>>>> mesh->GetPoint(pid);
>>>>                // std::cout<<    "Deleting"<<    j<<    "     "<<
>>>> pointToBeDeleted[0]<<""<<pointToBeDeleted[1]<<    ""<<
>>>>   pointToBeDeleted[2]
>>>> <<    std::endl;
>>>>
>>>>                 mesh->DeletePoint(pid);
>>>>            }
>>>>         }
>>>>         j++;
>>>>       }
>>>> _____________________________________
>>>> Powered by www.kitware.com
>>>>
>>>> Visit other Kitware open-source projects at
>>>> http://www.kitware.com/opensource/opensource.html
>>>>
>>>> Kitware offers ITK Training Courses, for more information visit:
>>>> http://www.kitware.com/products/protraining.html
>>>>
>>>> Please keep messages on-topic and check the ITK FAQ at:
>>>> http://www.itk.org/Wiki/ITK_FAQ
>>>>
>>>> Follow this link to subscribe/unsubscribe:
>>>> http://www.itk.org/mailman/listinfo/insight-users
>>>>
>>