我想使用vtk和python计算曲面上的曲率导数。我首先使用以下方法计算曲率：
curvatures = vtk.vtkCurvatures()
curvatures.SetInputConnection(reader.GetOutputPort())
curvatures.SetCurvatureTypeToGaussian()
并使用以下公式计算曲率的导数：
Derivativers = vtk.vtkCellDerivatives()
Derivativers.SetInputConnection(curvatures.GetOutputPort())
似乎与vtkCurvatures和vtkCellDerivatives的结果相同。
我应该怎么做才能获得曲面上的曲率导数。非常感谢！
最佳答案
我认为您的代码是正确的。但是我们需要确保曲率点数据数组是当前活动的标量数组。我已经附加了一个输入数据文件，您可以使用名称'Test.vtk'保存该文件。它有两个点数据数组-PointIds（一个标量数组）和PointNormals（一个矢量数组）。然后，我们将计算高斯曲率，该曲率将成为点数据的标量的第三个数组。我们将打印所有点数据数组的名称，而不管它们是标量还是向量。然后，我们将'Gauss_Curvature'标量数组显式设置为Active Scalar。我们将计算单元导数，这将创建一个称为'ScalarGradient'的单元数据向量数组，该数组将是曲率的梯度。这将保存在文件'Output.vtk'中
import vtk
rd = vtk.vtkPolyDataReader()
rd.SetFileName('Test.vtk')
curv = vtk.vtkCurvatures()
curv.SetInputConnection(rd.GetOutputPort())
curv.SetCurvatureTypeToGaussian()
curv.Update()
pd = curv.GetOutput()
for i in range(pd.GetPointData().GetNumberOfArrays()):
print(pd.GetPointData().GetArrayName(i))
# This will print the following:
# PointIds
# PointNormals
# Gauss_Curvature
# To set the active scalar to Gauss_Curvature
pd.GetPointData().SetActiveScalars('Gauss_Curvature')
curvdiff = vtk.vtkCellDerivatives()
curvdiff.SetInputData(pd)
curvdiff.SetVectorModeToComputeGradient()
curvdiff.Update()
writer = vtk.vtkPolyDataWriter()
writer.SetFileName('Output.vtk')
writer.SetInputConnection(curvdiff.GetOutputPort())
writer.Write()
给我以下输出-首先是曲率，然后是梯度。请注意，两个图中的色阶不同。因此，尽管颜色方案使曲率和导数值看起来相似，但它们是不同的。
如果要重现结果，则输入的vtk文件如下
# vtk DataFile Version 4.2
vtk output
ASCII
DATASET POLYDATA
POINTS 72 double
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1.0622264471 1.4540269048 -1.1853937884 0.8533187462 0.72833963362 -1.8409362444 0.161573121 1.415272931 -1.6182009866
-0.4682233113 2.0970647997 -0.17539653223 0.30090053169 1.9778473 -0.80327873468 -0.62604403311 1.746197318 -1.0984268611
0.62604948422 1.746195345 1.0984268742 0.4682298575 2.0970633231 0.17539654742 -0.30089435724 1.9778482191 0.80327874624
1.3794219731 1.1031586743 1.2360880686 1.9321437012 0.84755424016 0.44288858377 1.3329709879 1.6469225081 0.39813606858
-1.3329658439 1.6469266769 -0.39813605266 -1.3794185207 1.1031629885 -1.2360880529 -1.9321410548 0.84756028031 -0.44288857482
-0.16156870247 1.4152734137 1.6182009959 -1.0622219128 1.4540302146 1.1853938087 -0.85331647216 0.72834227646 1.8409362479
-1.7000771766 1.2495094572 0.44287862867 -2.0927638628 0.33092642637 0.39812667143 -1.6450795106 0.64303805991 1.2360797754
0.10502897512 0.5677157381 2.0771002606 -0.54417928828 -0.19289519204 2.0770984773 0.43913323132 -0.37482057542 2.077101172
1.0574135878 0.37481822068 1.8409414841 1.3064404335 -0.56771795917 1.6182050108 1.7903331906 0.19289323113 1.1854016225
-0.72812102639 -1.6469234624 1.18539471 -0.20411225533 -1.1031605232 1.8409380189 -1.1448850389 -0.84755547744 1.6181982897
0.26564737208 -1.7461967516 1.236085002 -0.23207016686 -2.0970637037 0.44288263714 0.75978960067 -1.9778489401 0.39813448025
1.1992202745 -1.4152750453 1.0984284306 1.5819944619 -1.4540310306 0.17539958384 1.8633106814 -0.72834386503 0.80328466622
-1.825278792 -0.33092031521 1.0984201446 -2.0502257619 -0.64303229501 0.17538963068 -1.5624229303 -1.2495043655 0.80327527281
-0.26565282447 -1.7461959014 -1.2360850131 0.23206361633 -2.0970644256 -0.44288265596 -0.7597957797 -1.977846564 -0.39813449851
-1.1992246997 -1.4152712955 -1.0984284473 -1.5819990123 -1.4540260972 -0.17539960215 -1.8633129661 -0.72833804688 -0.80328468018
0.20410881451 -1.1031611451 -1.8409380327 1.1448823984 -0.84755903977 -1.6181983017 0.72811588321 -1.6469257176 -1.1853947189
2.0502237661 -0.64303869999 -0.17538964133 1.5624190405 -1.2495092418 -0.80327529169 1.8252777661 -0.33092600698 -1.0984201511
-0.43913440065 -0.37481918558 -2.0771011678 -0.10502720377 0.56771608521 -2.0771002475 0.54417868626 -0.19289687027 -2.0770984714
-1.3064422115 -0.56771386838 -1.6182050202 -1.7903325818 0.19289882961 -1.185401614 -1.057412421 0.3748215375 -1.8409414839
-0.76083174443 1.3178134523 -1.9919051229 -0.7608358562 -1.3178110596 -1.9919051353 -2.4621262785 3.8465962003e-06 -0.47023127203
1.5216839818 -2.3645462409e-06 -1.991898872 2.4621262803 -3.846902628e-06 0.47023127288 1.2310617434 -2.1322669408 -0.47022115796
-1.2310684033 -2.1322631023 0.47022113869 -1.5216839821 2.3661982943e-06 1.9918988726 0.76083174316 -1.3178134534 1.9919051234
0.76083585779 1.317811059 1.9919051359 -1.2310617441 2.1322669425 0.47022115881 1.2310684021 2.1322631008 -0.47022113785
POLYGONS 140 560
3 12 14 9
3 27 69 24
3 70 21 19
3 1 53 63
3 2 14 13
3 38 36 37
3 28 68 36
3 39 67 23
3 64 38 51
3 13 14 12
3 20 24 18
3 34 35 33
3 40 41 39
3 16 58 17
3 20 18 19
3 26 27 24
3 11 6 70
3 10 14 71
3 22 39 23
3 6 10 7
3 3 5 7
3 29 64 13
3 41 30 32
3 57 45 47
3 54 61 57
3 66 30 41
3 50 43 42
3 30 33 31
3 33 35 36
3 65 37 35
3 37 36 35
3 26 68 28
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3 27 28 29
3 28 36 38
3 29 28 38
3 38 37 51
3 61 48 42
3 37 65 52
3 66 34 30
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3 26 31 68
3 64 29 38
3 12 69 27
3 18 9 11
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3 24 20 25
3 13 12 29
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3 18 11 19
3 11 9 10
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3 9 14 10
3 70 6 15
3 11 10 6
3 10 71 7
3 71 14 2
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3 6 8 15
3 21 17 22
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3 20 23 67
3 19 11 70
3 21 23 19
3 23 20 19
3 22 17 62
3 22 23 21
3 15 17 21
3 62 40 22
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3 58 16 59
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3 6 7 8
3 16 60 59
3 48 54 56
3 8 5 60
3 2 1 3
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3 3 1 4
3 2 3 71
3 71 3 7
3 3 4 5
3 5 55 60
3 49 50 48
3 8 60 16
3 60 55 59
3 4 55 5
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3 1 63 4
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3 49 53 52
3 2 0 1
3 1 0 53
3 0 51 53
3 0 64 51
3 13 64 0
3 2 13 0
POINT_DATA 72
SCALARS PointIds vtkIdType
LOOKUP_TABLE default
0 1 2 3 4 5 6 7 8
9 10 11 12 13 14 15 16 17
18 19 20 21 22 23 24 25 26
27 28 29 30 31 32 33 34 35
36 37 38 39 40 41 42 43 44
45 46 47 48 49 50 51 52 53
54 55 56 57 58 59 60 61 62
63 64 65 66 67 68 69 70 71
NORMALS PointNormals double
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0.27739675558 0.85505949665 0.43809165386 0.1561128187 0.97764027026 0.14088395868 -0.05910174957 0.91410169764 0.40115467037
0.6978536347 0.50139725414 0.51146954756 0.85786633279 0.46941626794 0.20907826874 0.63588503517 0.72681646701 0.25959207486
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关于python - 计算表面上的曲率导数，我们在Stack Overflow上找到一个类似的问题：https://stackoverflow.com/questions/51978524/