VTK使用矢量数据弯曲几何体

　　vtkWarpVector is a filter that modifies point coordinates by moving points along vector times the scale factor. Useful for showing flow profiles or mechanical deformation. The filter passes both its point data and cell data to its output.　

　　沿法向膨胀

#!/usr/bin/env python
import vtk

inputPolyData = vtk.vtkPolyData()

sphereSource = vtk.vtkSphereSource()
sphereSource.SetPhiResolution(15)
sphereSource.SetThetaResolution(15)
sphereSource.Update()
inputPolyData = sphereSource.GetOutput()

# merge duplicate points, and/or remove unused points and/or remove degenerate cells
clean = vtk.vtkCleanPolyData()
clean.SetInputData(inputPolyData)

# Generate normals
normals = vtk.vtkPolyDataNormals()
normals.SetInputConnection(clean.GetOutputPort())
normals.SplittingOff()

# vtkWarpVector is a filter that modifies point coordinates by moving points along vector times the scale factor
# Warp using the normals (deform geometry with vector data)
warp = vtk.vtkWarpVector()
warp.SetInputConnection(normals.GetOutputPort())

# Set the input data arrays that this algorithm will process
# The fieldAssociation refers to which field in the data object the array is stored
warp.SetInputArrayToProcess(0, 0, 0,vtk.vtkDataObject.FIELD_ASSOCIATION_POINTS, vtk.vtkDataSetAttributes.NORMALS)

# Specify value to scale displacement
warp.SetScaleFactor(1.0) 

# Visualize the original and warped models
colors = vtk.vtkNamedColors()

mapper = vtk.vtkPolyDataMapper()
mapper.SetInputConnection(warp.GetOutputPort())

warpedActor = vtk.vtkActor()
warpedActor.SetMapper(mapper)
warpedActor.GetProperty().SetColor(colors.GetColor3d("Flesh"))

originalMapper = vtk.vtkPolyDataMapper()
originalMapper.SetInputConnection(normals.GetOutputPort())

originalActor = vtk.vtkActor()
originalActor.SetMapper(originalMapper)
originalActor.GetProperty().SetInterpolationToFlat() # Set the shading interpolation method for an object
originalActor.GetProperty().SetColor(colors.GetColor3d("Flesh"))

renderWindow =vtk.vtkRenderWindow()
renderWindow.SetSize(640, 480)

# Create a camera for all renderers
camera = vtk.vtkCamera()

# Define viewport ranges: (xmin, ymin, xmax, ymax)
leftViewport = [0.0, 0.0, 0.5, 1.0]
rightViewport =[0.5, 0.0, 1.0, 1.0]

# Setup both renderers
leftRenderer = vtk.vtkRenderer()
leftRenderer.SetViewport(leftViewport)
leftRenderer.SetBackground(colors.GetColor3d("Burlywood"))
leftRenderer.SetActiveCamera(camera)

rightRenderer = vtk.vtkRenderer()
rightRenderer.SetViewport(rightViewport)
rightRenderer.SetBackground(colors.GetColor3d("CornFlower"))
rightRenderer.SetActiveCamera(camera)

leftRenderer.AddActor(originalActor)
rightRenderer.AddActor(warpedActor)

rightRenderer.ResetCamera()

renderWindow.AddRenderer(rightRenderer)
renderWindow.AddRenderer(leftRenderer)

style = vtk.vtkInteractorStyleTrackballCamera()

interactor = vtk.vtkRenderWindowInteractor()
interactor.SetRenderWindow(renderWindow)
interactor.SetInteractorStyle(style)

renderWindow.Render()
interactor.Start()

　　膨胀导入的STL模型

#!/usr/bin/env python
import vtk

inputPolyData = vtk.vtkPolyData()

readerSTL = vtk.vtkSTLReader()
readerSTL.SetFileName("Suzanne.stl")
readerSTL.Update()
inputPolyData = readerSTL.GetOutput()

# merge duplicate points, and/or remove unused points and/or remove degenerate cells
clean = vtk.vtkCleanPolyData()
clean.SetInputData(inputPolyData)

# Generate normals
normals = vtk.vtkPolyDataNormals()
normals.SetInputConnection(clean.GetOutputPort())
normals.SplittingOff() # Turn off the splitting of sharp edges

# vtkWarpVector is a filter that modifies point coordinates by moving points along vector times the scale factor
# Warp using the normals (deform geometry with vector data)
warp = vtk.vtkWarpVector()
warp.SetInputConnection(normals.GetOutputPort())

# Set the input data arrays that this algorithm will process
# The fieldAssociation refers to which field in the data object the array is stored
warp.SetInputArrayToProcess(0, 0, 0,vtk.vtkDataObject.FIELD_ASSOCIATION_POINTS, vtk.vtkDataSetAttributes.NORMALS)

# Specify value to scale displacement
warp.SetScaleFactor(0.3) 

# Visualize the original and warped models
colors = vtk.vtkNamedColors()

mapper = vtk.vtkPolyDataMapper()
mapper.SetInputConnection(warp.GetOutputPort())

warpedActor = vtk.vtkActor()
warpedActor.SetMapper(mapper)
warpedActor.GetProperty().SetColor(colors.GetColor3d("Flesh"))

originalMapper = vtk.vtkPolyDataMapper()
originalMapper.SetInputConnection(normals.GetOutputPort())

originalActor = vtk.vtkActor()
originalActor.SetMapper(originalMapper)
originalActor.GetProperty().SetInterpolationToFlat() # Set the shading interpolation method for an object
originalActor.GetProperty().SetColor(colors.GetColor3d("Flesh"))

renderWindow =vtk.vtkRenderWindow()
renderWindow.SetSize(640, 480)

# Create a camera for all renderers
camera = vtk.vtkCamera()

# Define viewport ranges: (xmin, ymin, xmax, ymax)
leftViewport = [0.0, 0.0, 0.5, 1.0]
rightViewport =[0.5, 0.0, 1.0, 1.0]

# Setup both renderers
leftRenderer = vtk.vtkRenderer()
leftRenderer.SetViewport(leftViewport)
leftRenderer.SetBackground(colors.GetColor3d("Burlywood"))
leftRenderer.SetActiveCamera(camera)

rightRenderer = vtk.vtkRenderer()
rightRenderer.SetViewport(rightViewport)
rightRenderer.SetBackground(colors.GetColor3d("CornFlower"))
rightRenderer.SetActiveCamera(camera)

leftRenderer.AddActor(originalActor)
rightRenderer.AddActor(warpedActor)

rightRenderer.ResetCamera()

renderWindow.AddRenderer(rightRenderer)
renderWindow.AddRenderer(leftRenderer)

style = vtk.vtkInteractorStyleTrackballCamera()

interactor = vtk.vtkRenderWindowInteractor()
interactor.SetRenderWindow(renderWindow)
interactor.SetInteractorStyle(style)

renderWindow.Render()
interactor.Start()

参考：

VTK: vtkWarpVector Class Reference

VTK/Examples/Cxx/PolyData/WarpSurface

VTK/Examples/Python/PolyData/WarpVector.py

An algorithm for inflating/deflating (offsetting, buffering) polygons