使用vtkAppendPolyData时如何更改VTK中对象的颜色？

Question

我正在尝试修改放置在vtkAppendPolyData中的每个对象的颜色，但是我得到了奇怪的颜色。我的意思是该对象不是一种颜色，而是每个表面都有不同的颜色。

我想按对象使用一种颜色。这是最小的示例：

import vtk
sphereSource = vtk.vtkSphereSource()
sphereSource.SetCenter(5,0,0)
sphereSource.Update()
Colors = vtk.vtkUnsignedCharArray()
Colors.SetNumberOfComponents(3)
Cellarray = sphereSource.GetOutput().GetPolys().GetNumberOfCells()
Colors.SetNumberOfTuples(Cellarray)
for c in range(Cellarray):
    Colors.InsertNextTuple3(255, 0, 0)

sphereSource.GetOutput().GetCellData().SetScalars(Colors)
sphereSource.Update()


coneSource =vtk.vtkConeSource()
coneSource.Update()
Colors = vtk.vtkUnsignedCharArray()
Colors.SetNumberOfComponents(3)
Cellarray = coneSource.GetOutput().GetPolys().GetNumberOfCells()
Colors.SetNumberOfTuples(Cellarray)
for c in range(Cellarray):
    Colors.InsertNextTuple3(0, 255, 0)
coneSource.GetOutput().GetCellData().SetScalars(Colors)
coneSource.Update()

# Append the two meshes
appendFilter = vtk.vtkAppendPolyData()
appendFilter.AddInputData(sphereSource.GetOutput())
appendFilter.AddInputData(coneSource.GetOutput())

appendFilter.Update()

#  Remove any duplicate points.
cleanFilter = vtk.vtkCleanPolyData()
cleanFilter.SetInputConnection(appendFilter.GetOutputPort())
cleanFilter.Update()

# Create a mapper and actor
mapper = vtk.vtkPolyDataMapper()
# mapper.ScalarVisibilityOn()
mapper.SetInputConnection(cleanFilter.GetOutputPort())
mapper.SetColorModeToDirectScalars()

actor = vtk.vtkActor()
actor.SetMapper(mapper)

# Create a renderer, render window, and interactor
renderer = vtk.vtkRenderer()
renderWindow = vtk.vtkRenderWindow()
renderWindow.AddRenderer(renderer)
renderWindowInteractor = vtk.vtkRenderWindowInteractor()
renderWindowInteractor.SetRenderWindow(renderWindow)

# Add the actors to the scene
renderer.AddActor(actor)
renderer.SetBackground(.3, .2, .1) #  Background color dark red

# Render and interact
renderWindow.Render()
renderWindowInteractor.Start()

Answer 1

设置元组数时，应使用InsertTuple3而不是InsertNextTuple3，如下所示：

Colors.SetNumberOfTuples(Cellarray)
for c in range(Cellarray):
    Colors.InsertTuple3(c, 255, 0, 0)

注意Insert在这里是一个令人困惑的名称，因为它不会更改全局大小，并且会覆盖给定的索引。更像是Set方法。