vtkPlaneWidget vtkProbeFilter speed issue

Hi,

The following is the work flow I used to probe a dynamic vector data volume and it output the correct results. However, it is quite slow (lagging) through the rendering. If I delete the line 5 (planeWidget->GetPolyData(plane); ), it becomes no lagging anymore but the results are not right. Could you explain how it works and any suggestion to replace line 5 to make it faster?

Thanks a lot.

Sean

vtkSmartPointer<vtkPlaneWidget> planeWidget;
vtkSmartPointer<vtkProbeFilter> probe;
vtkSmartPointer<vtkPolyData> plane;

1 planeWidget->SetOrigin(newOrigin[0], newOrigin[1], newOrigin[2]);
2 planeWidget->SetPoint1(newPoint1[0], newPoint1[1], newPoint1[2]);
3 planeWidget->SetPoint2(newPoint2[0], newPoint2[1], newPoint2[2]);

4 planeWidget->UpdatePlacement();
5 planeWidget->GetPolyData(plane);

6 probe->SetSourceConnection(reader->GetOutputPort());
7 probe->SetInputData(plane);
8 probe->Update();