BlankPoint was not showing the blanked point

src/Cxx/StructuredGrid/BlankPoint.cxx

@@ -7,9 +7,9 @@
 #include <vtkRenderWindowInteractor.h>
 #include <vtkRenderer.h>
 #include <vtkStructuredGrid.h>
+#include <vtkStructuredGridGeometryFilter.h>
 
 #include <iostream>
-#include <string>
 
 int main(int, char*[])
 {
@@ -22,6 +22,7 @@ int main(int, char*[])
 
   unsigned int gridSize = 8;
   unsigned int counter = 0;
+  unsigned int ptIdx = 0;
   // Create a 5x5 grid of points
   for (unsigned int j = 0; j < gridSize; j++)
   {
@@ -31,6 +32,7 @@ int main(int, char*[])
       {
         points->InsertNextPoint(i, j, 2);
         std::cout << "The different point is number " << counter << std::endl;
+        ptIdx = counter;
       }
       else
       {
@@ -41,12 +43,10 @@ int main(int, char*[])
     }
   }
 
-  // Specify the dimensions of the grid
+  // Specify the dimensions of the grid, set the points and blank one point.
   structuredGrid->SetDimensions(gridSize, gridSize, 1);
-
   structuredGrid->SetPoints(points);
-
-  structuredGrid->BlankPoint(27);
+  structuredGrid->BlankPoint(ptIdx);
   structuredGrid->Modified();
 
   // Check.
@@ -62,20 +62,27 @@ int main(int, char*[])
   };
 
   // Should not be visible.
-  isVisible(27);
+  isVisible(ptIdx);
   // Should be visible.
   isVisible(7);
 
-  // Create a mapper and actor
+  // We need the geometry filter to ensure that the
+  // blanked point and surrounding faces is missing.
+  vtkNew<vtkStructuredGridGeometryFilter>geometryFilter;
+  geometryFilter->SetInputData(structuredGrid);
+
+  // Create a mapper and actor.
   vtkNew<vtkDataSetMapper> gridMapper;
-  gridMapper->SetInputData(structuredGrid);
+  // gridMapper->SetInputData(structuredGrid);
+  gridMapper->SetInputConnection(geometryFilter->GetOutputPort());
+
 
   vtkNew<vtkActor> gridActor;
   gridActor->SetMapper(gridMapper);
   gridActor->GetProperty()->EdgeVisibilityOn();
   gridActor->GetProperty()->SetEdgeColor(colors->GetColor3d("Blue").GetData());
 
-  // Create a renderer, render window, and interactor
+  // Create a renderer, render window, and interactor.
   vtkNew<vtkRenderer> renderer;
   vtkNew<vtkRenderWindow> renderWindow;
   renderWindow->AddRenderer(renderer);
@@ -84,11 +91,11 @@ int main(int, char*[])
   vtkNew<vtkRenderWindowInteractor> renderWindowInteractor;
   renderWindowInteractor->SetRenderWindow(renderWindow);
 
-  // Add the actor to the scene
+  // Add the actor to the scene.
   renderer->AddActor(gridActor);
   renderer->SetBackground(colors->GetColor3d("ForestGreen").GetData());
 
-  // Render and interact
+  // Render and interact.
   renderWindow->Render();
 
   renderWindowInteractor->Start();

src/Python/StructuredGrid/BlankPoint.py

@@ -7,6 +7,7 @@ import vtkmodules.vtkRenderingOpenGL2
 from vtkmodules.vtkCommonColor import vtkNamedColors
 from vtkmodules.vtkCommonCore import vtkPoints
 from vtkmodules.vtkCommonDataModel import vtkStructuredGrid
+from vtkmodules.vtkFiltersGeometry import vtkStructuredGridGeometryFilter
 from vtkmodules.vtkRenderingCore import (
     vtkActor,
     vtkDataSetMapper,
@@ -19,46 +20,49 @@ from vtkmodules.vtkRenderingCore import (
 def main():
     colors = vtkNamedColors()
 
-    structured_grid = vtkStructuredGrid()
-
     points = vtkPoints()
 
     grid_size = 8
     counter = 0
+    pt_idx = 0
     # Create a 5x5 grid of points
     for j in range(0, grid_size):
         for i in range(0, grid_size):
             if i == 3 and j == 3:  # Make one point higher than the rest.
                 points.InsertNextPoint(i, j, 2)
-                print('The different point is number ', counter)
+                print(f'The different point is number {counter}.')
+                pt_idx = counter
             else:
                 # Make most of the points the same height.
                 points.InsertNextPoint(i, j, 0)
             counter += 1
 
-    # Specify the dimensions of the grid.
+    structured_grid = vtkStructuredGrid()
+    # Specify the dimensions of the grid, set the points and blank one point.
     structured_grid.SetDimensions(grid_size, grid_size, 1)
-
     structured_grid.SetPoints(points)
-
-    structured_grid.BlankPoint(27)
-    structured_grid.Modified()
+    structured_grid.BlankPoint(pt_idx)
 
     # Check.
     def is_visible(pt_num):
         if structured_grid.IsPointVisible(pt_num):
-            return f'Point {pt_num} is visible.'
+            return f'Point {pt_num:2d} is visible.'
         else:
-            return f'Point {pt_num} is not visible.'
+            return f'Point {pt_num:2d} is not visible.'
 
     # Should not be visible.
-    print(is_visible(27))
+    print(is_visible(pt_idx))
     # Should be visible.
     print(is_visible(7))
 
+    # We need the geometry filter to ensure that the
+    # blanked point and surrounding faces is missing.
+    geometry_filter = vtkStructuredGridGeometryFilter()
+    geometry_filter.SetInputData(structured_grid)
+
     # Create a mapper and actor.
     grid_mapper = vtkDataSetMapper()
-    grid_mapper.SetInputData(structured_grid)
+    grid_mapper.SetInputConnection(geometry_filter.GetOutputPort())
 
     grid_actor = vtkActor()
     grid_actor.SetMapper(grid_mapper)