[vtkusers] Finding neighboring points

[Sara Rolfe]

Hello,

I'm trying to find all the points connected to a vertex point in a  
polydata mesh.  I've followed the example here,

http://www.vtk.org/Wiki/VTK/Examples/Cxx/PolyData/CellPointNeighbors

And the email thread below, which both seem like what I want to do.
http://vtk.1045678.n5.nabble.com/Neighbours-of-a-point-in-a-mesh-td1236245.html

However, I'm having a problem when I try to use InsertNextId to add a  
point to the list of connected points.  I'm getting a bus error when I  
get to this line in the code.  Does anyone have an idea where this  
might be coming from?  I've checked that the ID I'm inserting is an  
int type, and the list is an empty vtkIdList.

Thanks,
Sara

my subroutine to find connected neighbors is below.

void GetConnectedVertices(vtkSmartPointer<vtkPolyData> mesh, int seed,  
vtkSmartPointer<vtkIdList> connectedVertices)
{
	vtkSmartPointer<vtkIdList> cellIdList =  
vtkSmartPointer<vtkIdList>::New();	//get all connected cells
	mesh->GetPointCells(seed, cellIdList);
	cout << "Got " << cellIdList->GetNumberOfIds() << " cells using point  
" << seed << endl;
	
	for(vtkIdType i = 0; i < cellIdList->GetNumberOfIds(); i++){		// loop  
through each cell using the seed point

		cout << "Checking cell " << i << endl;
		vtkCell* cell = mesh->GetCell(cellIdList->GetId(i));		// get current  
cell
		
		if(cell->GetNumberOfEdges() <= 0){				//if the cell doesn't have any  
edges, it is a line, so skip
			continue;
		}
		
		for(vtkIdType e = 0; e < cell->GetNumberOfEdges(); e++)				// loop  
through each edge of the cell
		{
			cout << "Checking edge " << e << endl;

			vtkCell* edge = cell->GetEdge(e);					// get current edge
			vtkIdList* pointIdList = edge->GetPointIds();				// get list of  
points on edge
			
			if(pointIdList->GetId(0) == seed || pointIdList->GetId(1) ==  
seed) // if one of the points on the edge are the vertex point
			{
				cout << "Writing connected point" << endl;

				if(pointIdList->GetId(0) == seed)				// if first point on edge is  
vertex									
				{
					int temp = pointIdList->GetId(1);			// get second point from list		
					cout << "Adding " << temp << " to list" << endl;

					connectedVertices->InsertNextId(temp);			// and insert it into  
connected point list													
				}
				else
				{
					int temp = pointIdList->GetId(0);			// get second point from list		
					cout << "Adding " << temp << " to list" << endl;
					connectedVertices->InsertNextId(temp);		// else insert first  
point into connected point list
				}
			}
		}
     }	
}

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