Method CleanAndCheckSurface

Filters/General/vtkIntersectionPolyDataFilter.cxx:2124–2184

}

void vtkIntersectionPolyDataFilter::CleanAndCheckSurface(
  vtkPolyData* pd, double stats[2], double tolerance)
{
  int badEdges = 0;
  int freeEdges = 0;
  vtkSmartPointer<vtkCleanPolyData> cleaner = vtkSmartPointer<vtkCleanPolyData>::New();
  vtkSmartPointer<vtkIntArray> bad = vtkSmartPointer<vtkIntArray>::New();
  vtkSmartPointer<vtkIntArray> freeedge = vtkSmartPointer<vtkIntArray>::New();
  vtkSmartPointer<vtkIdList> edgeneighbors = vtkSmartPointer<vtkIdList>::New();

  // Clean the input surface
  cleaner->SetInputData(pd);
  cleaner->ToleranceIsAbsoluteOn();
  cleaner->SetAbsoluteTolerance(tolerance);
  cleaner->Update();
  pd->DeepCopy(cleaner->GetOutput());
  pd->BuildLinks();

  // Loop through the surface and find edges with cells that have either more
  // than one neighbor or no neighbors. No neighbors can be okay,as this can
  // indicate a free edge. However, for a polydata surface, multiple neighbors
  // indicates a bad cell with possible intersecting facets!
  for (int i = 0; i < pd->GetNumberOfCells(); i++)
  {
    const vtkIdType* pts = nullptr;
    vtkIdType npts = 0;
    pd->GetCellPoints(i, npts, pts);
    int badcell = 0;
    int freeedgecell = 0;
    for (int j = 0; j < npts; j++)
    {
      vtkIdType p0 = pts[j];
      vtkIdType p1 = pts[(j + 1) % npts];

      pd->GetCellEdgeNeighbors(i, p0, p1, edgeneighbors);
      if (edgeneighbors->GetNumberOfIds() > 1)
      {
        badEdges++;
        badcell++;
      }
      else if (edgeneighbors->GetNumberOfIds() < 1)
      {
        freeEdges++;
        freeedgecell++;
      }
    }
    bad->InsertValue(i, badcell);
    freeedge->InsertValue(i, freeedgecell);
  }

  bad->SetName("BadTriangle");
  pd->GetCellData()->AddArray(bad);
  pd->GetCellData()->SetActiveScalars("BadTriangle");

  freeedge->SetName("FreeEdge");
  pd->GetCellData()->AddArray(freeedge);
  pd->GetCellData()->SetActiveScalars("FreeEdge");