def vertex_normal (dataset) :
"Returns the vertex normal of each point in a dataset."
if not dataset : raise RuntimeError, 'Need a dataset to compute vertex_normal'
ds = dataset.NewInstance()
ds.UnRegister(None)
ds.CopyStructure(dataset.VTKObject)
filter = vtk.vtkPolyDataNormals()
filter.SetInputData(ds)
filter.ComputeCellNormalsOff()
filter.ComputePointNormalsOn()
filter.SetFeatureAngle(180)
filter.SplittingOff()
filter.ConsistencyOff()
filter.AutoOrientNormalsOff()
filter.FlipNormalsOff()
filter.NonManifoldTraversalOff()
filter.Update()
varray = filter.GetOutput().GetPointData().GetNormals()
ans = dataset_adapter.vtkDataArrayToVTKArray(varray, dataset)
# The association information has been lost over the vtk filter
# we must reconstruct it otherwise lower pipeline will be broken.
ans.Association = dataset_adapter.ArrayAssociation.POINT
return ans
def calculer_surface_moyenne(surface_1, surface_2, precision=1e-6, pas_initial=10):
"""fonction qui calcule une surface moyenne par la methode des spheres inscrites
extension de la methode des cercles inscrits
"""
# conversion en polydata et fusion des blocs
surface_1 = convertir_surface_en_polydata(surface_1)
surface_2 = convertir_surface_en_polydata(surface_2)
#calcul du vecteur Normals
normals = vtk.vtkPolyDataNormals()
normals.SetInput(surface_1)
normals.Update()
surface_1_modif = normals.GetOutput()
# derafinement de la surface_1
#derafiner = vtk.vtkCleanPolyData()
#derafiner.SetInput(surface_1_modif)
#derafiner.SetToleranceIsAbsolute(1)
#derafiner.SetAbsoluteTolerance(1)
#derafiner.Update()
#surface_1_modif = derafiner.GetOutput()
# calcul de la surface moyenne
surface_moyenne = trouver_centres_spheres_inscrites(surface_1_modif, surface_2,
precision = precision, pas_initial = pas_initial)
normals = vtk.vtkPolyDataNormals()
normals.SetInput(surface_moyenne)
normals.ConsistencyOn()
normals.Update()
surface_moyenne = normals.GetOutput()
coords = numpy_support.vtk_to_numpy(surface_moyenne.GetPoints().GetData())
normals = numpy_support.vtk_to_numpy(surface_moyenne.GetPointData().GetArray('Normals'))
inf = coords - normals * 1e3
sup = coords + normals * 1e3
source = vtk.vtkLineSource()
source.SetPoint1(inf[0])
source.SetPoint2(sup[0])
# return source.GetOutput()
return surface_moyenne
