# [vtkusers] How to create a cube with vtkPolyData

Jothy jothybasu at gmail.com
Tue May 18 06:14:32 EDT 2010

```Screenshot is here!

On Tue, May 18, 2010 at 11:12 AM, Jothy <jothybasu at gmail.com> wrote:

> Hi David,
>
> I tried the vtkHexahedron example. But, when I try to cut this I get a line
> across the cut plane . see the screenshot and also the code.
>
> Could you please figure it out?
>
> from vtk import*
>
>
> #Setup the coordinates of eight points
> #(the two faces must be in counter clockwise order as viewd from the
> outside)
> P0 = [0.0, 0.0, 0.0];
> P1 = [1.0, 0.0, 0.0];
> P2 = [1.0, 1.0, 0.0];
> P3 = [0.0, 1.0, 0.0];
> P4 = [0.0, 0.0, 1.0];
> P5 = [1.0, 0.0, 1.0];
> P6 = [1.0, 1.0, 1.0];
> P7 = [0.0, 1.0, 1.0];
>
>
> #Create the points
> points = vtkPoints();
> points.InsertNextPoint(P0);
> points.InsertNextPoint(P1);
> points.InsertNextPoint(P2);
> points.InsertNextPoint(P3);
> points.InsertNextPoint(P4);
> points.InsertNextPoint(P5);
> points.InsertNextPoint(P6);
> points.InsertNextPoint(P7);
>
> #Create a hexahedron from the points
> hexa = vtkHexahedron();
> hexa.GetPointIds().SetId(0,0);
> hexa.GetPointIds().SetId(1,1);
> hexa.GetPointIds().SetId(2,2);
> hexa.GetPointIds().SetId(3,3);
> hexa.GetPointIds().SetId(4,4);
> hexa.GetPointIds().SetId(5,5);
> hexa.GetPointIds().SetId(6,6);
> hexa.GetPointIds().SetId(7,7);
>
> #Add the hexahedron to a cell array
> hexs = vtkCellArray();
> hexs.InsertNextCell(hexa);
>
> #Add the points and hexahedron to an unstructured grid
> uGrid =vtkUnstructuredGrid();
> uGrid.SetPoints(points);
> uGrid.InsertNextCell(hexa.GetCellType(), hexa.GetPointIds());
> aBeamMapper = vtkDataSetMapper()
> aBeamMapper.SetInput(uGrid)
> aBeamActor = vtkActor()
> aBeamActor.SetMapper(aBeamMapper)
> aBeamActor.GetProperty().SetColor(1,1,0)
> aBeamActor.GetProperty().SetOpacity(0.60)
> aBeamActor.GetProperty().EdgeVisibilityOn()
> aBeamActor.GetProperty().SetEdgeColor(1,1,1)
> aBeamActor.GetProperty().SetLineWidth(1.5)
>
> #create a plane to cut,here it cuts in the XZ direction (xz
> normal=(1,0,0);XY =(0,0,1),YZ =(0,1,0)
> plane=vtkPlane()
> plane.SetOrigin(0.5,0,0)
> plane.SetNormal(1,0,0)
>
> #create cutter
> cutter=vtkCutter()
> cutter.SetCutFunction(plane)
> cutter.SetInput(aBeamActor.GetMapper().GetInput())
> cutter.Update()
> cutterMapper=vtkPolyDataMapper()
> cutterMapper.SetInputConnection( cutter.GetOutputPort())
>
> #create plane actor
> planeActor=vtkActor()
> planeActor.GetProperty().SetColor(1,0.5,0.5)
> planeActor.GetProperty().SetLineWidth(2)
> planeActor.SetMapper(cutterMapper)
>
> # Setup a renderer, render window, and interactor
> renderer = vtkRenderer()
> renderWindow = vtkRenderWindow()
> #renderWindow.SetWindowName("Test")
>
> renderWindowInteractor = vtkRenderWindowInteractor()
> renderWindowInteractor.SetRenderWindow(renderWindow)
>
> #Add the actor to the scene
> renderer.SetBackground(0,0,0) # Background color white
>
> #Render and interact
> renderWindow.Render()
> *
> *
> I think it has be passed through a filter. But what it's that??
>
> Thanks,
>
> Jothy
>
>
>
> On Mon, May 17, 2010 at 10:08 PM, David Doria <daviddoria+vtk at gmail.com<daviddoria%2Bvtk at gmail.com>>
> wrote:
> > On Mon, May 17, 2010 at 5:03 PM, Jothy <jothybasu at gmail.com> wrote:
> >> Hi all,
> >>
> >> I want to create a hexahedron using vtkPolyData. I think there is no
> >> example in wiki. I created it with a vtkHexaHedron but when I cut it
> >> it produces a line across the cut section.I don't want this. I am not
> >> able to solve this problem for many months.I used it passing through
> >> vtkstripper, vtkTriangle. Finally found that only if the input is of
> >> vtkPolyData, cutter will not produce that line across the cut section.
> >> Can some with kind enough :), add an example of how to create cube or
> >> cone with vtkPoldata.
> >>
> >> Many thanks,
> >>
> >> Jothy
> >
> > I don't really understand your question. The title and your last
> > sentence talk about cubes and cones
> >
> > http://www.vtk.org/Wiki/VTK/Examples/GeometricObjects/Cube
> > http://www.vtk.org/Wiki/VTK/Examples/GeometricObjects/Display/Cone
> >
> > but the beginning talks about hexahedrons
> >
> > http://www.vtk.org/Wiki/VTK/Examples/GeometricObjects/Hexahedron
> >
> > Let us know if these links do not help.
> >
> > David
> >
>
>
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