[vtkusers] refinement of iso surface

[Dale "Luke" Peterson]

Bill,
  Thanks for the reply.

> VTK does not have an adaptive isosurface algorithm. You can increase the
> dimensions of your sampling and then apply one of several decimation
> algorithms to reduce the polygons. The decimation algorithms will keep more
> polygons in areas with more detail.

Would it make sense to perhaps use a very course grid on the 3D volume
(vtkSampleFunction), then do subdivision
(vtkButterflySubdivisionFilter) on the output of the contour filter to
increase the number of triangles, and then do decimation to reduce the
number of polygons in areas that don't need it?

When I start to increase the number of points in vtkSampleFunction,
things get slow because this increases with n^3, but with the
SubDivision approach I think I would be ~n^2 since it would only be
subdividing the surface.

~Luke

> see for example:
> http://vtk.org/Wiki/VTK/Examples/Cxx/Meshes/Decimation
> and
> http://vtk.org/Wiki/VTK/Examples/Cxx/Meshes/QuadricDecimation



>
>
> On Thu, Jul 5, 2012 at 6:51 PM, Dale "Luke" Peterson <hazelnusse at gmail.com>
> wrote:
>>
>> > If you mean "refine" as smoothing use vtkWindowedSincPolyDataFilter.
>>
>> I guess I would like more points to be added in areas where the
>> curvature is high so that the surface is more accurately represented.
>> Does the Sinc filter do that?  If not, is there something like [0] or
>> [1] in VTK?
>>
>> Luke
>>
>> [0] -- Isosurface Computation Made Simple: Hardware Acceleration,
>> Adaptive Refinement and Tetrahedral Stripping, Pascucci, V.
>> [1] -- Time critical isosurface refinement and smoothing, Pascuci, V.,
>> Bajaj, C. doi://10.1145/353888.353894
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>
>
>
> --
> Unpaid intern in BillsBasement at noware dot com
>



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