Re: 答复: 答复: [vtkusers] the adjacent vertex

[Mike Jackson]

You may want to look at the vtkConnectivity filter. I have used that  
as a basis for other types of "Connectivity" algorithms on poly data.

Cheers
-- 
Mike Jackson   Senior Research Engineer
Innovative Management & Technology Services


On Jan 4, 2007, at 7:53 AM, PAUL wrote:

>      vtkCubeSource *pCube = vtkCubeSource::New();
>
>      pCube->SetCenter(0,0,0);
>
>      pCube->SetXLength(2);
>
>      pCube->SetYLength(2);
>
>      pCube->SetZLength(2);
>
>      vtkPolyData *data = pCube->GetOutput();
>
>      data->Update();
>
>      int i;
>
>      int cellCount = data->GetNumberOfCells();
>
>      int pointCount = data->GetNumberOfPoints();
>
>      vtkIdList *ptsIDList = vtkIdList::New();
>
>      ptsIDList->Allocate(pointCount);
>
>      for (i=0;i<pointCount;i++) {
>
>          ptsIDList->InsertNextId(i);
>
>      }
>
>
>
>          vtkIdList *CurrentcellPts = vtkIdList::New();
>
>          data->GetCellPoints(0,CurrentcellPts);
>
>
>
>          vtkIdType ptIdinCurrentCell = CurrentcellPts->GetId(0);
>
>
>
>          vtkIdList *cellIDList = vtkIdList::New();
>
>          data->GetCellNeighbors(i,ptsIDList,cellIDList);
>
>          int ptscount = ptsIDList->GetNumberOfIds();
>
>          int cellcount = cellIDList->GetNumberOfIds();
>
>
>
> cellcount whould be the number of cells which is adjacent to 0  
> cell.But cellcount is 0. why?
>
>
>
>
>
> -----邮件原件-----
> 发件人: Dominik Szczerba [mailto:domi at vision.ee.ethz.ch]
> 发送时间: 2007年1月4日 18:48
> 收件人: vtkusers at vtk.org
> 抄送: PAUL
> 主题: Re: 答复: [vtkusers] the adjacent vertex
>
>
>
> On a second thought the below will not capture all the connected  
> points
>
> directly, only at a cell. But you can achieve what you want by  
> combining
>
> it with GetCellNeighbours.
>
> Another way is to first walk the cells maping them to their points  
> (e,g.
>
> using std::map) and then walk the points retreiving the cells and  
> their
>
> points. Rejecting duplicates you get what you are after.
>
> -DS
>
>
>
> Dominik Szczerba wrote:
>
> > You can locate the cell containing the point of interest and call
>
> > GetCellPoints().
>
> > DS
>
> >
>
> > PAUL wrote:
>
> >> Hello all:
>
> >>
>
> >> I have been baffled the question for a long time.
>
> >>
>
> >> I am studying an algorithm of judging convex or non-convex  
> polyhedron.
>
> >>
>
> >> If  every  vertex  is above the plane which contain three vertexes
>
> >> adjacent to the vertex, the polyhedron is convex .
>
> >>
>
> >> For an example, there are eight vertexes on a cube. And each  
> vertex is
>
> >> adjacent to three other vertexes.
>
> >>
>
> >> My question is:
>
> >>
>
> >> When an arbitrary vertex is accessed, how to know the other three
>
> >> vertexes’ coordinate?
>
> >>
>
> >>
>
> >>
>
> >> I need your helps! Thank you!!
>
> >>
>
> >>
>
> >>
>
> >>
>
> >>
>
> >>  
> ---------------------------------------------------------------------- 
> --
>
> >>
>
> >> *发件人:* vtkusers-bounces+polinzhuo=163.com at vtk.org
>
> >> [mailto:vtkusers-bounces+polinzhuo=163.com at vtk.org] *代表 *PAUL
>
> >> *发送时间:* 2007年1月4日 13:44
>
> >> *收件人:* vtkusers at vtk.org
>
> >> *主题:* [vtkusers] the adjacent vertex
>
> >>
>
> >>
>
> >>
>
> >> Hi,all:
>
> >>
>
> >> There is an arbitrary vertex on a polyhedron. How to find the other
>
> >> three vertexes which are adjacent to the vertex?
>
> >>
>
> >> Paul
>
> >>
>
> >>
>
> >>
>
> >>
>
> >>  
> ---------------------------------------------------------------------- 
> --
>
> >>
>
> >> _______________________________________________
>
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>
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>
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>
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>
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>
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>
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>
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