[vtkusers] help with finding a surface

[Jérôme]

Hi,
when you say that your scalar range is [0,192], I understand that the
maximum density of point inside a voxel is 192 and the minimum is 0.
Colourly talking, 0 is blue, 192 is red. Tell me if I am wrong. From the
screenshots you shared, I saw that your data change smoothly from 0 to 192:
it won't be that easy to select the scalar between "inside" and "outside".
You will have to arbitrarily set a minimum value from which your consider
the density to be reliable.

The result you expect cannot be directly extracted from isosurfaces, as I
guess that the maximum density is not 192 everywhere. You want to find a
surface that (sort of) maximizes the density. From what I know, deformable
models are able to do such a maximization. I don't think that something
exists in VTK.

I have 2 suggestions, both requiring the use of external VTK filters :
- use vtkThreshold (native VTK) in order to get only the points with
reliable density. then use this point cloud in a surface reconstruction
algorithm (Poisson is available on VTK journal, and I think there are
others)
- Get a somewhat correct surface from marching cube (such as you the one you
already got) and use it as an initialization for a deformable (I submitted a
deformation framework in VTK in the VTKJournal)

HTH
Jerome

2011/6/15 nuno.jf <nunofernandes7 at gmail.com>

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