# EllipticalCylinder

VTKExamples/Python/GeometricObjects/EllipticalCylinder

### Description

The example creates an elliptical cross-section and stores it in a vtkPolyData. Then, the vtkLinearExtrusionFilter creates an elliptical cylinder by extruding the vtkPolyLine along a vector. The example sets the backface property of the vtkActor to show the front and back face of the cylinder.

See

also EllipticalCylinderDemo to see the vtkPolyLine and the vector represented as an oriented arrow.

### Code

EllipticalCylinder.py

    #!/usr/bin/env python
    # -*- coding: utf-8 -*-

    import math

    import vtk

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

        angle = 0
        r1 = 50
        r2 = 30
        centerX = 10.0
        centerY = 5.0

        points = vtk.vtkPoints()
        idx = 0
        while angle <= 2.0 * vtk.vtkMath.Pi() + (vtk.vtkMath.Pi() / 60.0):
            points.InsertNextPoint(r1 * math.cos(angle) + centerX,
                                   r2 * math.sin(angle) + centerY,
                                   0.0)
            angle = angle + (vtk.vtkMath.Pi() / 60.0)
            idx += 1

        line = vtk.vtkPolyLine()
        line.GetPointIds().SetNumberOfIds(idx)
        for i in range(0, idx):
            line.GetPointIds().SetId(i, i)

        lines = vtk.vtkCellArray()
        lines.InsertNextCell(line)

        polyData = vtk.vtkPolyData()
        polyData.SetPoints(points)
        polyData.SetLines(lines)

        extrude = vtk.vtkLinearExtrusionFilter()
        extrude.SetInputData(polyData)
        extrude.SetExtrusionTypeToNormalExtrusion()
        extrude.SetVector(0, 0, 100.0)
        extrude.Update()

        lineMapper = vtk.vtkPolyDataMapper()
        lineMapper.SetInputData(polyData)

        lineActor = vtk.vtkActor()
        lineActor.SetMapper(lineMapper)
        lineActor.GetProperty().SetColor(colors.GetColor3d("Peacock"))

        mapper = vtk.vtkPolyDataMapper()
        mapper.SetInputConnection(extrude.GetOutputPort())

        back = vtk.vtkProperty()
        back.SetColor(colors.GetColor3d("Tomato"))

        actor = vtk.vtkActor()
        actor.SetMapper(mapper)
        actor.GetProperty().SetColor(colors.GetColor3d("Banana"))
        actor.SetBackfaceProperty(back)

        ren = vtk.vtkRenderer()
        ren.SetBackground(colors.GetColor3d("SlateGray"))
        ren.AddActor(actor)
        ren.AddActor(lineActor)

        renWin = vtk.vtkRenderWindow()
        renWin.SetWindowName("Elliptical Cylinder")
        renWin.AddRenderer(ren)
        renWin.SetSize(600, 600)

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

        style = vtk.vtkInteractorStyleTrackballCamera()
        iren.SetInteractorStyle(style)

        camera = vtk.vtkCamera()
        camera.SetPosition(0, 1, 0)
        camera.SetFocalPoint(0, 0, 0)
        camera.SetViewUp(0, 0, 1)
        camera.Azimuth(30)
        camera.Elevation(30)

        ren.SetActiveCamera(camera)
        ren.ResetCamera()
        ren.ResetCameraClippingRange()

        renWin.Render()
        iren.Start()

    if __name__ == '__main__':
        main()