ImplicitQuadric

#!/usr/bin/env python

# noinspection PyUnresolvedReferences
import vtkmodules.vtkInteractionStyle
# noinspection PyUnresolvedReferences
import vtkmodules.vtkRenderingOpenGL2
from vtkmodules.vtkCommonColor import vtkNamedColors
from vtkmodules.vtkCommonDataModel import vtkQuadric
from vtkmodules.vtkFiltersCore import vtkContourFilter
from vtkmodules.vtkImagingHybrid import vtkSampleFunction
from vtkmodules.vtkRenderingCore import (
    vtkActor,
    vtkPolyDataMapper,
    vtkRenderWindow,
    vtkRenderWindowInteractor,
    vtkRenderer
)


def main():
    colors = vtkNamedColors()

    # create an ellipsoid using a implicit quadric
    quadric = vtkQuadric()
    quadric.SetCoefficients(0.5, 1, 0.2, 0, 0.1, 0, 0, 0.2, 0, 0)

    # The sample function generates a distance function from the implicit
    # function. This is then contoured to get a polygonal surface.
    sample = vtkSampleFunction()
    sample.SetImplicitFunction(quadric)
    sample.SetModelBounds(-0.5, 0.5, -0.5, 0.5, -0.5, 0.5)
    sample.SetSampleDimensions(40, 40, 40)
    sample.ComputeNormalsOff()

    # contour
    surface = vtkContourFilter()
    surface.SetInputConnection(sample.GetOutputPort())
    surface.SetValue(0, 0.0)

    # mapper
    mapper = vtkPolyDataMapper()
    mapper.SetInputConnection(surface.GetOutputPort())
    mapper.ScalarVisibilityOff()
    actor = vtkActor()
    actor.SetMapper(mapper)
    actor.GetProperty().EdgeVisibilityOn()
    actor.GetProperty().SetColor(colors.GetColor3d('AliceBlue'))
    actor.GetProperty().SetEdgeColor(colors.GetColor3d('SteelBlue'))

    # A renderer and render window
    renderer = vtkRenderer()
    renderer.SetBackground(colors.GetColor3d('Silver'))

    # add the actor
    renderer.AddActor(actor)

    # render window
    renwin = vtkRenderWindow()
    renwin.AddRenderer(renderer)
    renwin.SetWindowName('ImplicitQuadric')

    # An interactor
    interactor = vtkRenderWindowInteractor()
    interactor.SetRenderWindow(renwin)

    # Start
    interactor.Initialize()
    renwin.Render()
    interactor.Start()


if __name__ == '__main__':
    main()