vtkContourFilter produces a bisecting ridge
This issue was created automatically from an original Mantis Issue. Further discussion may take place here.
A pipeline of vtkContourFilter (or vtkKitwareContourFilter) and vtkSmoothPolyDataFilter produces a ridge along the cut of an otherwise smooth isosurface and a plane that approximately bisects the isosurface.
This happens for other data sets as well, the ridge is alwas along the middle.
In an older VTK version [vtk version 4.5.0, vtk source $Revision: 1.2095 $, $Date: 2005/02/04 02:46:59 $ (GMT)], it only happens with vtkKitwareContourFilter and not with vtkContourFilter but in the current version [vtk version 4.5.0, vtk source $Revision: 1.2155 $, $Date: 2005/04/05 01:47:08 $ (GMT)], the problem is visible in both versions.
Goodwin Lawlor suggested that I use vtkMarchingCubes instead. This produced the correct output.
See this post in the mailing list for a script and data set that reproduces the bug:
http://public.kitware.com/pipermail/vtkusers/2005-April/079267.html