[vtkusers] refinement of iso surface

[Bill Lorensen]

Subdivision wont add any more detail. It will just make the artifacts worse
I think.

On Thu, Jul 5, 2012 at 7:43 PM, Dale "Luke" Peterson
<hazelnusse at gmail.com>wrote:

> 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
> >
>
>
>
> --
> "People call me a perfectionist, but I'm not. I'm a rightist. I do
> something until it's right, and then I move on to the next thing."
> -- James Cameron
>



-- 
Unpaid intern in BillsBasement at noware dot com
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