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# IceCream

VTKEx/Python/VisualizationAlgorithms/IceCream

### Description

This example demonstrates how to use boolean combinations of implicit functions to create a model of an ice cream cone.

Other languages

See (Cxx), (Java)

Question

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### Code

IceCream.py

    #!/usr/bin/env python

    """
    This example demonstrates how to use boolean combinations of implicit
     functions to create a model of an ice cream cone.

    """
    import vtk

    def main():
        colors = vtk.vtkNamedColors()

        # Create implicit function primitives. These have been carefully placed to
        # give the effect that we want. We are going to use various combinations of
        # these functions to create the shape we want for example, we use planes
        # intersected with a cone (which is infinite in extent) to get a finite
        # cone.
        #
        cone = vtk.vtkCone()
        cone.SetAngle(20)

        vertPlane = vtk.vtkPlane()
        vertPlane.SetOrigin(.1, 0, 0)
        vertPlane.SetNormal(-1, 0, 0)

        basePlane = vtk.vtkPlane()
        basePlane.SetOrigin(1.2, 0, 0)
        basePlane.SetNormal(1, 0, 0)

        iceCream = vtk.vtkSphere()
        iceCream.SetCenter(1.333, 0, 0)
        iceCream.SetRadius(0.5)

        bite = vtk.vtkSphere()
        bite.SetCenter(1.5, 0, 0.5)
        bite.SetRadius(0.25)

        # Combine primitives to build ice-cream cone. Clip the cone with planes.
        theCone = vtk.vtkImplicitBoolean()
        theCone.SetOperationTypeToIntersection()
        theCone.AddFunction(cone)
        theCone.AddFunction(vertPlane)
        theCone.AddFunction(basePlane)

        # Take a bite out of the ice cream.
        theCream = vtk.vtkImplicitBoolean()
        theCream.SetOperationTypeToDifference()
        theCream.AddFunction(iceCream)
        theCream.AddFunction(bite)

        # The sample function generates a distance function from the
        # implicit function (which in this case is the cone). This is
        # then contoured to get a polygonal surface.
        #
        theConeSample = vtk.vtkSampleFunction()
        theConeSample.SetImplicitFunction(theCone)
        theConeSample.SetModelBounds(-1, 1.5, -1.25, 1.25, -1.25, 1.25)
        theConeSample.SetSampleDimensions(128, 128, 128)
        theConeSample.ComputeNormalsOff()

        theConeSurface = vtk.vtkContourFilter()
        theConeSurface.SetInputConnection(theConeSample.GetOutputPort())
        theConeSurface.SetValue(0, 0.0)

        coneMapper = vtk.vtkPolyDataMapper()
        coneMapper.SetInputConnection(theConeSurface.GetOutputPort())
        coneMapper.ScalarVisibilityOff()

        coneActor = vtk.vtkActor()
        coneActor.SetMapper(coneMapper)
        coneActor.GetProperty().SetColor(colors.GetColor3d("chocolate"))

        # The same here for the ice cream.
        #
        theCreamSample = vtk.vtkSampleFunction()
        theCreamSample.SetImplicitFunction(theCream)
        theCreamSample.SetModelBounds(0, 2.5, -1.25, 1.25, -1.25, 1.25)
        theCreamSample.SetSampleDimensions(128, 128, 128)
        theCreamSample.ComputeNormalsOff()

        theCreamSurface = vtk.vtkContourFilter()
        theCreamSurface.SetInputConnection(theCreamSample.GetOutputPort())
        theCreamSurface.SetValue(0, 0.0)

        creamMapper = vtk.vtkPolyDataMapper()
        creamMapper.SetInputConnection(theCreamSurface.GetOutputPort())
        creamMapper.ScalarVisibilityOff()

        creamActor = vtk.vtkActor()
        creamActor.SetMapper(creamMapper)
        creamActor.GetProperty().SetDiffuseColor(colors.GetColor3d("mint"))
        creamActor.GetProperty().SetSpecular(.6)
        creamActor.GetProperty().SetSpecularPower(50)

        # Create the usual rendering stuff.
        #
        ren1 = vtk.vtkRenderer()

        renWin = vtk.vtkRenderWindow()
        renWin.AddRenderer(ren1)

        iren = vtk.vtkRenderWindowInteractor()
        iren.SetRenderWindow(renWin)

        # Add the actors to the renderer, set the background and size.
        #
        ren1.AddActor(coneActor)
        ren1.AddActor(creamActor)
        ren1.SetBackground(colors.GetColor3d("SlateGray"))
        renWin.SetSize(640, 480)
        ren1.ResetCamera()
        ren1.GetActiveCamera().Roll(90)
        ren1.GetActiveCamera().Dolly(1.25)
        ren1.ResetCameraClippingRange()
        iren.Initialize()

        # render the image
        #
        renWin.Render()
        iren.Start()

    if __name__ == '__main__':
        main()