PlatonicSolids

VTKExamples/Python/GeometricObjects/PlatonicSolids


Description

Display all five Platonic solids in a grid.

Platonic solids are regular, convex polyhedrons. They are constructed by congruent (identical in shape and size) regular (all angles equal and all sides equal) polygonal faces with the same number of faces meeting at each vertex.

Five solids satisfy the above criteria:

Figure Tetrahedron Cube Octahedron Icosahedron Dodecahedron
Vertices 4 8 6 (2 × 3) 12 (4 × 3) 20 (8 + 4 × 3)
Edges 6 12 12 30 30
Faces 4 6 8 20 12

The relationship between vertices, edges and faces is given by Euler's formula:

V - E + F = 2

Code

PlatonicSolids.py

#!/usr/bin/env python

import vtk


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

    # Each face has a different cell scalar
    # Here we create a lookup table with a different colour
    # for each face. The colors have been carefully
    # chosen so that adjacent cells are colored distinctly.
    lut = vtk.vtkLookupTable()
    lut.SetNumberOfTableValues(20)
    lut.SetTableRange(0.0, 19.0)
    lut.Build()
    lut.SetTableValue(0, 0.1, 0.1, 0.1)
    lut.SetTableValue(1, 0, 0, 1)
    lut.SetTableValue(2, 0, 1, 0)
    lut.SetTableValue(3, 0, 1, 1)
    lut.SetTableValue(4, 1, 0, 0)
    lut.SetTableValue(5, 1, 0, 1)
    lut.SetTableValue(6, 1, 1, 0)
    lut.SetTableValue(7, 0.9, 0.7, 0.9)
    lut.SetTableValue(8, 0.5, 0.5, 0.5)
    lut.SetTableValue(9, 0.0, 0.0, 0.7)
    lut.SetTableValue(10, 0.5, 0.7, 0.5)
    lut.SetTableValue(11, 0, 0.7, 0.7)
    lut.SetTableValue(12, 0.7, 0, 0)
    lut.SetTableValue(13, 0.7, 0, 0.7)
    lut.SetTableValue(14, 0.7, 0.7, 0)
    lut.SetTableValue(15, 0, 0, 0.4)
    lut.SetTableValue(16, 0, 0.4, 0)
    lut.SetTableValue(17, 0, 0.4, 0.4)
    lut.SetTableValue(18, 0.4, 0, 0)
    lut.SetTableValue(19, 0.4, 0, 0.4)

    mappers = list()
    actors = list()
    textMappers = list()
    textActors = list()
    renderers = list()

    # Create a common text property.
    textProperty = vtk.vtkTextProperty()
    textProperty.SetFontSize(16)
    textProperty.SetJustificationToCentered()

    # Create the render window and interactor.
    renWin = vtk.vtkRenderWindow()
    renWin.SetWindowName("Platonic Solids")

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

    # Create the source, renderer, mapper
    # and actor for each object.
    PlatonicSolids = list()
    # There are five Platonic solids.
    names = ["Tetrahedron", "Cube", "Octahedron", "Icosahedron", "Dodecahedron"]
    for i in range(0, len(names)):
        PlatonicSolids.append(vtk.vtkPlatonicSolidSource())
        PlatonicSolids[i].SetSolidType(i)

        mappers.append(vtk.vtkPolyDataMapper())
        mappers[i].SetInputConnection(PlatonicSolids[i].GetOutputPort())
        mappers[i].SetLookupTable(lut)
        mappers[i].SetScalarRange(0, 19)

        actors.append(vtk.vtkActor())
        actors[i].SetMapper(mappers[i])

        textMappers.append(vtk.vtkTextMapper())
        textMappers[i].SetInput(names[i])
        textMappers[i].SetTextProperty(textProperty)

        textActors.append(vtk.vtkActor2D())
        textActors[i].SetMapper(textMappers[i])
        textActors[i].SetPosition(120, 16)

        renderers.append(vtk.vtkRenderer())
        renderers[i].AddActor(actors[i])
        renderers[i].AddViewProp(textActors[i])

        renWin.AddRenderer(renderers[i])

    # Setup the viewports
    xGridDimensions = 3
    yGridDimensions = 2
    rendererSize = 300
    renWin.SetSize(rendererSize * xGridDimensions, rendererSize * yGridDimensions)
    for row in range(0, yGridDimensions):
        for col in range(0, xGridDimensions):
            index = row * xGridDimensions + col

            # (xmin, ymin, xmax, ymax)
            viewport = [float(col) / xGridDimensions,
                        float(yGridDimensions - (row + 1)) / yGridDimensions,
                        float(col + 1) / xGridDimensions,
                        float(yGridDimensions - row) / yGridDimensions]

            if index > (len(actors) - 1):
                # Add a renderer even if there is no actor.
                # This makes the render window background all the same color.
                ren = vtk.vtkRenderer()
                ren.SetBackground(colors.GetColor3d("SlateGray"))
                ren.SetViewport(viewport)
                renWin.AddRenderer(ren)
                continue

            renderers[index].SetViewport(viewport)
            renderers[index].SetBackground(colors.GetColor3d("SlateGray"))
            renderers[index].ResetCamera()
            renderers[index].GetActiveCamera().Azimuth(4.5)
            renderers[index].GetActiveCamera().Elevation(-18)
            renderers[index].ResetCameraClippingRange()

    iRen.Initialize()
    renWin.Render()
    iRen.Start()


if __name__ == "__main__":
    main()