[vtkusers] Isosurface opacity problem

[Sebastien Jourdain]

I don't know if it is a VTK problem, but ParaView is using vtk 5.6 (at least).
On the other hand I don't know the underneath setting inside ParaView
for the opacity.
Maybe you can ask what are those setting so you can reproduce them
inside your vtk application on the ParaView mailing list.

Seb

PS: How did you set the depth peeling/sorting inside your code ?

2010/12/17 이현철 <basalt76 at gmail.com>:
> Yes it looks normal in ParaView.
>
> But In my application, after applying depth sorting,
> the iso-surface looks like attached file.
>
> Is it vtk version problem ? My vtk is 5.2.1
>
> 2010년 12월 17일 오후 9:59, Sebastien Jourdain <sebastien.jourdain at kitware.com>님의
> 말:
>>
>> Ok,
>>
>> but this is normal because the ContourFilter will generate a triangulated
>> mesh.
>>
>> Seb
>>
>> 2010/12/17 이현철 <basalt76 at gmail.com>:
>> > I sent you two images, input file and iso-contour image.
>> > I had no problem to look at input file and iso-contour.
>> >
>> > Problem is
>> > when I set Representation option with "Surface with edges".
>> >
>> > Input file image looks normal but iso-contour image gone through
>> > vtkMarchingContourFilter  has triangles.
>> > Thank you very much.
>> >
>> > 2010년 12월 17일 오후 5:35, Sebastien Jourdain
>> > <sebastien.jourdain at kitware.com>님의
>> > 말:
>> >>
>> >> The reason is because you ask to look at the input file and not the
>> >> iso-contour. The little eye on the left is disable in front of the
>> >> contour.
>> >>
>> >> Seb
>> >>
>> >> PS: Once you change something on a filter, don't forget to click on
>> >> Apply
>> >>
>> >> 2010/12/17 이현철 <basalt76 at gmail.com>:
>> >> > I'm very sorry for bothering you.
>> >> >
>> >> > I got something interesting.
>> >> >
>> >> > In the ParaView, when I set Representation with "Surface with edges".
>> >> >
>> >> > The isosurface image went through vtkMarchingContourFilter has the
>> >> > triangles.
>> >> > But the original image looks normal.
>> >> >
>> >> > I have used vtkCleanPolyData and vtkPolyDataNormals.
>> >> >
>> >> > I attached two iamges.
>> >> >
>> >> > Thank you ver much.
>> >> >
>> >> > Lee.
>> >> >
>> >> > 2010년 12월 17일 오후 12:55, 이현철 <basalt76 at gmail.com>님의 말:
>> >> >>
>> >> >> Thank you for your advice
>> >> >>
>> >> >> I loaded my isosurface into ParaView and set opacity under 1.0.
>> >> >> It looks normal ~
>> >> >>
>> >> >> Is this means that the ParaView do something special to solve
>> >> >> transparency
>> >> >> problem ?
>> >> >>
>> >> >> I attached the result.
>> >> >>
>> >> >> 2010년 12월 15일 오후 11:21, Sebastien Jourdain
>> >> >> <sebastien.jourdain at kitware.com>님의 말:
>> >> >>>
>> >> >>> How did you defined your unstructured grid ? It seems that some
>> >> >>> inner
>> >> >>> surface are detected...
>> >> >>> This could happen if you duplicate the points so each cell has its
>> >> >>> own
>> >> >>> points ?
>> >> >>>
>> >> >>> Try to load your data into ParaView and see if you can reproduce
>> >> >>> the
>> >> >>> problem.
>> >> >>>
>> >> >>> Seb
>> >> >>>
>> >> >>> 2010/12/15 이현철 <basalt76 at gmail.com>:
>> >> >>> > Sorry to interrupt you again.
>> >> >>> >
>> >> >>> > I attach two images.
>> >> >>> >
>> >> >>> > Before and after adding depth sorting.
>> >> >>> > There are some differences.
>> >> >>> >
>> >> >>> > My graphics card seems not to support depth peeling.
>> >> >>> >
>> >> >>> > Thank you very mush.
>> >> >>> >
>> >> >>> > Lee.
>> >> >>> >
>> >> >>> > 2010/12/15 Sebastien Jourdain <sebastien.jourdain at kitware.com>
>> >> >>> >>
>> >> >>> >> You should enable depth peeling on the renderer to fix most of
>> >> >>> >> the
>> >> >>> >> artefact. But the rendering will be slower.
>> >> >>> >>
>> >> >>> >> Seb
>> >> >>> >>
>> >> >>> >> On Tue, Dec 14, 2010 at 10:01 AM, 이현철 <basalt76 at gmail.com>
>> >> >>> >> wrote:
>> >> >>> >> > Dears
>> >> >>> >> >
>> >> >>> >> > I visualized isosurface using vtkMarchingContourFilter from
>> >> >>> >> > vtkUnstructuredGrid.
>> >> >>> >> >
>> >> >>> >> > When the opacity is 1.0 , created picture looks normal.
>> >> >>> >> >
>> >> >>> >> > But when i adjust opacity to below 1.0, the picture has
>> >> >>> >> > speckles
>> >> >>> >> > depends
>> >> >>> >> > on the position.
>> >> >>> >> >
>> >> >>> >> > Do you have any solution ?
>> >> >>> >> >
>> >> >>> >> > I'll really appreciate it.
>> >> >>> >> >
>> >> >>> >> > Attached images
>> >> >>> >> >
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