Question

我想生成一个由向量组件着色的vtkUnstructuredGrid图。我可以通过在paraview中阅读下面代码生成的vtu文件来做到这一点，我可以选择例如位移矢量的y分量。但是，我无法在python脚本中直接弄清楚如何执行此操作。通过设置变量＆＃39;组件＆＃39;等于0我按预期得到x分量。我似乎无法选择任何其他组件进行展示。

一种可能性可能是使用计算过滤器并创建一个新的标量数组，但我确信有一种更简单的方法。非常感谢任何帮助。

import vtk

grid = vtk.vtkUnstructuredGrid()
points = vtk.vtkPoints()
cells = vtk.vtkCellArray()
disp = vtk.vtkFloatArray()
disp.SetNumberOfComponents(3)
disp.SetName('displacement')

N = 11
delta = 10./(N-1)
for kz in range(N):
    for ky in range(N):
        for kx in range(N):
            points.InsertNextPoint(kx*delta,ky*delta,kz*delta)
            disp.InsertNextTuple3(kx,kx*ky,ky**2+kz**2)
grid.SetPoints(points)
pdata = grid.GetPointData()
pdata.AddArray(disp)

inel = [0,1,N+1,N,N**2,N**2+1,N**2+N+1,N**2+N]
for kz in range(N-1):
    for ky in range(N-1):
        for kx in range(N-1):
            anEle = vtk.vtkHexahedron()
            for kk in range(8):
                anEle.GetPointIds().SetId(kk,inel[kk]+kx+N*ky+N**2*kz)
            cells.InsertNextCell(anEle)
grid.SetCells(vtk.VTK_HEXAHEDRON,cells)

if 1==11:
    writer = vtk.vtkXMLUnstructuredGridWriter();
    writer.SetDataModeToAscii()
    writer.SetFileName('bricks.vtu')
    writer.SetInput(grid)
    writer.Write()

else:
    grid.GetPointData().SetActiveScalars('displacement')

    # create a rendering window and renderer
    ren = vtk.vtkRenderer()
    renWin = vtk.vtkRenderWindow()
    renWin.AddRenderer(ren)

    # create a renderwindowinteractor
    iren = vtk.vtkRenderWindowInteractor()
    iren.SetRenderWindow(renWin)

    # mapper
    mapper = vtk.vtkDataSetMapper()
    mapper.SetInput(grid)
    component = 1
    vrange = grid.GetPointData().GetArray(0).GetRange(component)
    mapper.SetScalarRange(vrange)

    # actor
    actor = vtk.vtkActor()
    actor.SetMapper(mapper)
    p=actor.GetProperty()
    p.SetEdgeVisibility(True)

    # assign actor to the renderer
    ren.AddActor(actor)

    #########################################################################
    #             Define view
    #########################################################################
    ViewSize = [1253, 817]
    CenterOfRotation = [5.0, 5.0, 5.0]
    CameraPosition = [23, 20, 30]
    CameraFocalPoint = [5,5,5]
    CameraViewUp = [0,1,0]
    CameraParallelScale = 9
    Background = [0.9,0.9,0.9]

    renWin.SetSize(ViewSize)
    camera = ren.GetActiveCamera()
    camera.SetFocalPoint(CenterOfRotation)
    camera.SetPosition(CameraPosition)
    camera.SetFocalPoint(CameraFocalPoint)
    camera.SetViewUp(CameraViewUp)
    camera.SetParallelScale(CameraParallelScale)
    ren.SetBackground(Background)

    #########################################################################
    #             Add color bar
    #########################################################################
    cmap = vtk.vtkDiscretizableColorTransferFunction()
    cmap.AddRGBPoint(vrange[0],1,0,0)
    cmap.AddRGBPoint(vrange[1],1,1,1)
    cmap.SetNumberOfValues(20)
    cmap.SetDiscretize(True)
    cmap.SetVectorModeToComponent()
    cmap.SetVectorComponent(component)

    mapper.SetLookupTable(cmap)
    scalarBar = vtk.vtkScalarBarActor()
    scalarBar.SetLookupTable(cmap)
    scalarBar.SetTitle('displacement')
    ren.AddActor2D(scalarBar)


    renderLarge = vtk.vtkWindowToImageFilter()
    renderLarge.SetInput(renWin)
    renderLarge.SetMagnification(4)

    writer = vtk.vtkPNGWriter()
    writer.SetInputConnection(renderLarge.GetOutputPort())
    writer.SetFileName('bricks.png')
    renWin.SetOffScreenRendering(True)
    renWin.Render()
    writer.Write()

Answer 1

可能现在已经太晚了。但是，提取特定组件的一种方法是使用vtkDataArray.CopyComponent（）方法。我附上一小段python代码来做你想做的事。

# initialise a new vtkFloatArray to copy any component from disp
dispSelComponent = vtk.vtkFloatArray()


N = 11
delta = 10./(N-1)
for kz in range(N):
    for ky in range(N):
        for kx in range(N):
            points.InsertNextPoint(kx*delta,ky*delta,kz*delta)
            disp.InsertNextTuple3(kx,kx*ky,ky**2+kz**2)
grid.SetPoints(points)


noTuples = disp.GetNumberOfTuples()
noComponents = disp.GetNumberOfComponents()
dispSelComponent.SetNumberOfTuples(noTuples)
dispSelComponent.SetNumberOfComponents(1)
wantedComp = 2
dispSelComponent.CopyComponent(0, disp, wantedComp)

pdata = grid.GetPointData()
pdata.AddArray(dispSelComponent)

我希望这能帮到你。

绘制vtk矢量组件作为颜色映射

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