[vtkusers] Problems in applying an adaptive subdivision algorithm using vtk

[Dimitris Andritsos]

Hello All,

I am trying to implement an algorithm that performs adjustment and adaptive 
subdivision of a polygonal mesh approximation of an implicit surface. I am 
using Marching Cubes to obtain a coarse approximation of the mesh and 
afterwards I am working with that.

The algorithm depends very much on the normals at the vertices and centers 
of the triangular mesh. So before beginning with the algorithm I use 
vtkPolyDataNormals to obtain the normals at the vertices and the triangle 
centers of the mesh that results from Marching Cubes. Then I use the output 
from vtkPolyDataNormals as input to the algorithm. Up to this point there is 
no problem .After performing some iterations with the algorithm, the 
topology of the mesh changes and so should the normals. However I haven't 
managed to succeed in changing these. Although, I am calling Update for the 
mesh after each iteration of the algorithm the normals remain the same. But 
if each time I create a new instance of vtkPolyDataNormals and use that to 
compute the normals then these appear to be different from iteration to 
iteration. I would really appreaciate any help on how this should be 
correctly done.

The second problem has to do with insertion of new triangles. I would like 
your help on what would be the best way to update the PolyData mesh each 
time a triangle is split. I am working with InsertNextLinkedCell and Point 
but I am getting strange debug errors.

Thank you very much in advance,
Dimitris

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