text: """For each point finds the 12 closest ones and fit a sphere.
  Color points from the size of the sphere radius."""
  from vedo import *
  from vedo.pyplot import histogram
  
  plt = Plotter()
  
  s = plt.load(dataurl+"cow.vtk").alpha(0.3)
  
  pts1, pts2, vals, cols = [], [], [], []
  
  for i in range(0, s.N(), 10):
      p = s.points(i)
      pts = s.closestPoint(p, N=12)  # find the N closest points to p
      sph = fitSphere(pts)           # find the fitting sphere
      if sph is None:
          continue
  
      value = sph.radius * 10
      color = colorMap(value, "jet", 0, 1)  # map value to a RGB color
      n = versor(p - sph.center)  # unit vector from sphere center to p
      vals.append(value)
      cols.append(color)
      pts1.append(p)
      pts2.append(p + n / 8)
  
  plt += Points(pts1, c=cols)
  plt += Lines(pts1, pts2, c="black")
  plt += histogram(vals, xtitle='radius', xlim=[0,2]).pos(-1,0.5,-1)
  plt += __doc__
  
  plt.show().close()
  