[vtkusers] add or copy polydata to an other

[Frederic Danesi]

Hi, 

The problem is here : first->GetPolys()->InsertNextCell(tempD->GetCell(i));

tempD->GetCell(i) return a cell that includes pointsIds from tempD ... which
do not match to pointsIds in "first" ...

A simple way to do that is to use vtkAppendPolyData. It will do the work for
you ...
You may try something like this :

>         vtkCollectionIterator* iter = vtkCollectionIterator::New();
>         iter->SetCollection(importer->GetRenderer()->GetActors());
>         iter->InitTraversal();	
	   vtkAppendPolyData *allInOne = vtkAppendPolyData::New();
>         while (!iter->IsDoneWithTraversal())
>         {
>             vtkPolyData* tempD =
(vtkPolyData*)((vtkActor*)iter->GetCurrentObject())->GetMapper()->GetInput()
;
>      	 allInOne->AddInput(tempD);
>             iter->GoToNextItem();
>         }
	   vtkPolyData *allMyPolyData = allInOne->GetOutput();	

If you really want to do it by yourself, you have to rebuild the point Ids,
for example by managing a correspondence table between point's Id in tempD
and the matching Id in firstPolyData after inserting the point...

Be careful, this will not merge duplicate points ...

Fred.

Cordialement,
F.Danesi.
--
Département DINCCS (Département Ingénierie Numérique, Conception
Collaborative et Simulation) 
MICADO / DINCCS 
Pole de Haute Technologie, 7 boulevard Jean Delautre (IFTS) 
08000 Charleville-Mézières 
Tel. : 03.24.41.69.55 / 06.62.76.13.32 
Email : frederic.danesi at dinccs.com 
Web: www.afmicado.com / www.dinccs.com

> -----Message d'origine-----
> De : Marian Panten [mailto:usted_y_yo at web.de]
> Envoyé : samedi 16 février 2008 16:06
> À : vtkusers at vtk.org
> Objet : [vtkusers] add or copy polydata to an other
> 
> Hi,
> 
> I've got a collection of actors and am trying to copy/add the point and
> cell data of the collection into the polydata of the first actor. I have
> tried something like this.
> 
>         vtkCollectionIterator* iter = vtkCollectionIterator::New();
>         iter->SetCollection(importer->GetRenderer()->GetActors());
>         iter->InitTraversal();
>         vtkActor* fristActor = (vtkActor*) iter->GetCurrentObject();
>         vtkPolyData* firstPolyData = (vtkPolyData*)
> temp->GetMapper()->GetInput();
>         iter->GoToNextItem();
> 
>         while (!iter->IsDoneWithTraversal())
>         {
>             vtkPolyData* tempD = (vtkPolyData*)
> ((vtkActor*)iter->GetCurrentObject())->GetMapper()->GetInput();
>             vtkIdType nPts = tempD->GetPoints()->GetNumberOfPoints();
>             vtkIdType nCells = tempD->GetPolys()->GetNumberOfCells();
>             for (vtkIdType i = 0; i<nPts; i++)
>             {
> 
>  first->GetPoints()->InsertNextPoint(tempD->GetPoints()->GetPoint(i));
>             }
>             for (vtkIdType i = 0; i<nCells; i++)
>             {
>                 vtkIdType nCout  = first->GetPolys()->GetNumberOfCells();
>                 first->GetPolys()->InsertNextCell(tempD->GetCell(i));
>                 first->GetPolys()->UpdateCellCount(nCout+1);
>                 first->GetPolys()->Modified();
>             }
>             iter->GoToNextItem();
>         }
> 
> The adding of the points seems to work, but I've got problems with the
> cell data, resulting in a runtime error. I've tried a lot, but can't
> find a solution.
> Does anyone have any idea? I must say I am new in vtk and maybe I have
> overseen an easier way to do this. I would be very glad if someone could
> send me a code snippet.
> 
> Thanks a lot
> Marian