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How can make the smoothed vtk mesh vertices distribute evenly?

After smoothing the contour constructed by MatchingCubes with below codes,

contour=vtk.vtkMarchingCubes()
smoother = vtk.vtkWindowedSincPolyDataFilter()

The result seem like below. Some vertices are unevenly distributed. Is there any method to make them more 'evenly segmented'?

enter image description here

Solution

  • For other users looking for an answer from this post:

    C++ using VTK https://github.com/valette/ACVD

    python using pyvista / VTK https://github.com/pyvista/pyacvd ($ pip install pyacvd)

    Example using pyacvd from a function that converts a simpleITK binary image to a VTK polydata:

    import numpy as np
import SimpleITK as sitk
import vtk
from vtk.util import numpy_support
import pyvista as pv
import pyacvd

def sitk2vtk(self, sitk_pointer, nb_points=None):    
    numpy_array = sitk.GetArrayFromImage(sitk_pointer)
    size = list(sitk_pointer.GetSize())
    origin = list(sitk_pointer.GetOrigin())
    spacing = list(sitk_pointer.GetSpacing())
    label = numpy_support.numpy_to_vtk(num_array=numpy_array.ravel(), deep=True, array_type=vtk.VTK_FLOAT)
    
    # Convert the VTK array to vtkImageData
    img_vtk = vtk.vtkImageData()
    img_vtk.SetDimensions(size)
    img_vtk.SetSpacing(spacing)
    img_vtk.SetOrigin(origin)
    img_vtk.GetPointData().SetScalars(label)

    MarchingCubeFilter = vtk.vtkDiscreteMarchingCubes()   
    MarchingCubeFilter.SetInputData(img_vtk)
    MarchingCubeFilter.GenerateValues(1, 1, 1)   
    MarchingCubeFilter.Update() 

    if nb_points:        
        # wrapper vtk polydata to pyvista polydata        
        pv_temp = pv.PolyData(MarchingCubeFilter.GetOutput())        
        cluster = pyacvd.Clustering(pv_temp)        
        cluster.cluster(int(nb_points))        
        remesh = cluster.create_mesh()        
        remesh_vtk = vtk.vtkPolyData()        
        remesh_vtk.SetPoints(remesh.GetPoints())        
        remesh_vtk.SetVerts(remesh.GetVerts())        
        remesh_vtk.SetPolys(remesh.GetPolys())        
        return remesh_vtk    
    else:        
        return MarchingCubeFilter.GetOutput()

    Some examples for ITK/VTK reader/writer/converter: https://github.com/guatavita/IOTools