TriangleColoredPoints

import vtk

# setup points and vertices
Points = vtk.vtkPoints()
Vertices = vtk.vtkCellArray()

id = Points.InsertNextPoint(1.0, 0.0, 0.0)
Vertices.InsertNextCell(1)
Vertices.InsertCellPoint(id)
id = Points.InsertNextPoint(0.0, 0.0, 0.0)
Vertices.InsertNextCell(1)
Vertices.InsertCellPoint(id)
id = Points.InsertNextPoint(0.0, 1.0, 0.0)
Vertices.InsertNextCell(1)
Vertices.InsertCellPoint(id)

# setup colors
Colors = vtk.vtkUnsignedCharArray()
Colors.SetNumberOfComponents(3)
Colors.SetName("Colors")
Colors.InsertNextTuple3(255, 0, 0)
Colors.InsertNextTuple3(0, 255, 0)
Colors.InsertNextTuple3(0, 0, 255)

polydata = vtk.vtkPolyData()
polydata.SetPoints(Points)
polydata.SetVerts(Vertices)
polydata.GetPointData().SetScalars(Colors)
polydata.Modified()
if vtk.VTK_MAJOR_VERSION <= 5:
    polydata.Update()

writer = vtk.vtkXMLPolyDataWriter()
writer.SetFileName("TriangleColoredPoints.vtp")
if vtk.VTK_MAJOR_VERSION <= 5:
    writer.SetInput(polydata)
else:
    writer.SetInputData(polydata)
writer.Write()