[vtkusers] Cannot see imagedata behind transparent polydata

Mon Mar 8 08:36:39 EST 2010

Is your imagedate 2D? 3D? How do you display your imagedata (ie what's
your pipeline)?
If your imagedata is 3D and by "displaying imagedata" you mean volume
rendering, then no you cannot mixed translucent polygonal geometry and
volume rendering.

On Mon, Mar 8, 2010 at 8:05 AM, Mathieu P <mtp.vtk at gmail.com> wrote:
> Hi,
>
> I have done some tests, and i can see image data behind transparent
> polydata, but i cannot see polydata behind transparent image data with depth
> peeling method !
>
> It's very strange because without depthpeeling, it's workling well both
> sides.
>
>
> Cordialement,
>
> -- Mathieu PICCIN
>
>
>
>
> On Thu, Mar 4, 2010 at 10:22 AM, Mathieu P <mtp.vtk at gmail.com> wrote:
>>
>> Martin,
>>
>> The solution of using depth peeling doesnt come from me, but from Francois
>> Bertel, from KitWare.
>> I dont know how do make depth peeling working with transparent polygons...
>>
>>
>>
>> Cordialement,
>>
>> -- Mathieu PICCIN
>>
>>
>>
>>
>> On Thu, Mar 4, 2010 at 9:31 AM, Martin Allerstorfer
>> <allerstorfer_martin at gmx.at> wrote:
>>>
>>> But the biggest problem I have at the moment is that I cannot see the
>>> imagedata behind transparent polygons? Sorry for writting so many questions
>>> but it is quite urgent for me.
>>>
>>> Thank you so much,
>>> Martin
>>>
>>> > I just found out that it works also with imagedata but only for certain
>>> > distances.
>>> > If I zoom into the imagedata suddenly polydata is shown behind
>>> > imagedata,
>>> > but it should be the other way round.
>>> > Is there an additional parameter to define the distance where depth
>>> > peeling starts?
>>> >
>>> > Thanks,
>>> > Martin
>>> >
>>> > > Datum: Thu, 04 Mar 2010 08:45:38 +0100
>>> > > Von: "Martin Allerstorfer" <allerstorfer_martin at gmx.at>
>>> > > An: vtkusers at vtk.org
>>> > > Betreff: [vtkusers] Cannot see imagedata behind transparent polydata
>>> >
>>> > > Thanks for all the answers! Mathieu, your suggestion using depth
>>> > > pealing
>>> > > works for polydata, but if I want to use imagedata in the same
>>> > > renderer
>>> > > depth calculation does not work between polydata and imagedata? A
>>> > solution for
>>> > > this problem would be great!
>>> > >
>>> > > Thanks,
>>> > > Martin
>>> > >
>>> > > >Dealing with non opaque geometry requires sorting the polygon to be
>>> > > >rendered. It would be extremely slow if it was
>>> > > >activated by default.
>>> > > >
>>> > > >Try to use depth peeling. Follow these steps:
>>> > > >
>>> > > >http://www.vtk.org/Wiki/VTK/Depth_Peeling#VTK_calls
>>> > > >
>>> > > >You need OpenGL>=2.0 for it to work.
>>> > > >
>>> > > >On Wed, Mar 3, 2010 at 12:35 PM, Mathieu P <mtp.vtk at gmail.com>
>>> > wrote:
>>> > > >> I have attached a small image illustrating my problem.
>>> > > >>
>>> > > >> I cannot believe VTK cannot manage object opacity !
>>> > > >>
>>> > > >> Thanks for help.
>>> > > >>
>>> > > >>
>>> > > >> Cordialement,
>>> > > >>
>>> > > >> -- Mathieu PICCIN
>>> > > >>
>>> > > >>
>>> > > >>
>>> > > >>
>>> > > >> On Wed, Mar 3, 2010 at 4:50 PM, Mathieu P <mtp.vtk at gmail.com>
>>> > wrote:
>>> > > >>>
>>> > > >>> Actually i am using vtkImageActor and i change their opacity with
>>> > > >>> setOpacity...
>>> > > >>>
>>> > > >>>
>>> > > >>> Cordialement,
>>> > > >>>
>>> > > >>> -- Mathieu PICCIN
>>> > > >>>
>>> > > >>>
>>> > > >>>
>>> > > >>>
>>> > > >>> On Wed, Mar 3, 2010 at 3:57 PM, Mathieu P <mtp.vtk at gmail.com>
>>> > > wrote:
>>> > > >>>>
>>> > > >>>> Same kind of problem here :
>>> > > >>>>
>>> > > >>>> I have two imageData :
>>> > > >>>>
>>> > > >>>> Image data A loaded first
>>> > > >>>> Image data B loaded after
>>> > > >>>>
>>> > > >>>> i modify the opacity to 50% for both image data.
>>> > > >>>> i can see tough the image data B, so the last loaded, but i
>>> > > >>>> cannot
>>> > > see
>>> > > >>>> toughthe image data A, the first loaded.
>>> > > >>>> Modifying the opacity of the forst loaded change only its
>>> > luminosity
>>> > > (or
>>> > > >>>> alpha).
>>> > > >>>>
>>> > > >>>>
>>> > > >>>> Cordialement,
>>> > > >>>>
>>> > > >>>> -- Mathieu PICCIN
>>> > > >>>>
>>> > > >>>>
>>> > > >>>>
>>> > > >>>>
>>> > > >>>> On Wed, Mar 3, 2010 at 3:03 PM, Martin Allerstorfer
>>> > > >>>> <allerstorfer_martin at gmx.at> wrote:
>>> > > >>>>>
>>> > > >>>>> Hi,
>>> > > >>>>>
>>> > > >>>>> In my rendering view I would like to show imagedata and
>>> > additionally
>>> > > >>>>> some information using transparent glyphs. But not all glyphs
>>> > > >>>>> have
>>> > > the same
>>> > > >>>>> transparency. So I change the color and alpha settings for each
>>> > cell
>>> > > of the
>>> > > >>>>> glyphs seperately. Unfortunately now I cannot see the volume
>>> > behind
>>> > > the
>>> > > >>>>> transparent polydata. Does anybody know how to solve this
>>> > > >>>>> problem?
>>> > > >>>>>
>>> > > >>>>> Thanks,
>>> > > >>>>> Martin
>>> > > >>>>> --
>>> > > >>>>> GRATIS für alle GMX-Mitglieder: Die maxdome Movie-FLAT!
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>>> > > >>>>> _______________________________________________
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>>> > > >>>>>
>>> > > >>>>> Visit other Kitware open-source projects at
>>> > > >>>>> http://www.kitware.com/opensource/opensource.html
>>> > > >>>>>
>>> > > >>>>> Please keep messages on-topic and check the VTK FAQ at:
>>> > > >>>>> http://www.vtk.org/Wiki/VTK_FAQ
>>> > > >>>>>
>>> > > >>>>> Follow this link to subscribe/unsubscribe:
>>> > > >>>>> http://www.vtk.org/mailman/listinfo/vtkusers
>>> > > >>>>
>>> > > >>>
>>> > > >>
>>> > > >>
>>> > > >> _______________________________________________
>>> > > >> Powered by www.kitware.com
>>> > > >>
>>> > > >> Visit other Kitware open-source projects at
>>> > > >> http://www.kitware.com/opensource/opensource.html
>>> > > >>
>>> > > >> Please keep messages on-topic and check the VTK FAQ at:
>>> > > >> http://www.vtk.org/Wiki/VTK_FAQ
>>> > > >>
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>>> > > >>
>>> > > >>
>>> > >
>>> > >
>>> > > --
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>>> > > Jetzt freischalten unter http://portal.gmx.net/de/go/maxdome01
>>> > > _______________________________________________
>>> > > Powered by www.kitware.com
>>> > >
>>> > > Visit other Kitware open-source projects at
>>> > > http://www.kitware.com/opensource/opensource.html
>>> > >
>>> > > Please keep messages on-topic and check the VTK FAQ at:
>>> > > http://www.vtk.org/Wiki/VTK_FAQ
>>> > >
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>>> >
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>>> > _______________________________________________
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>>> >
>>> > Visit other Kitware open-source projects at
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>>> >
>>> > Please keep messages on-topic and check the VTK FAQ at:
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>>> >
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>>> _______________________________________________
>>> Powered by www.kitware.com
>>>
>>> Visit other Kitware open-source projects at
>>> http://www.kitware.com/opensource/opensource.html
>>>
>>> Please keep messages on-topic and check the VTK FAQ at:
>>> http://www.vtk.org/Wiki/VTK_FAQ
>>>
>>> Follow this link to subscribe/unsubscribe:
>>> http://www.vtk.org/mailman/listinfo/vtkusers
>>
>
>
> _______________________________________________
> Powered by www.kitware.com
>
> Visit other Kitware open-source projects at
> http://www.kitware.com/opensource/opensource.html
>
> Please keep messages on-topic and check the VTK FAQ at:
> http://www.vtk.org/Wiki/VTK_FAQ
>
> Follow this link to subscribe/unsubscribe:
> http://www.vtk.org/mailman/listinfo/vtkusers
>
>

-- 
François Bertel, PhD  | Kitware Inc. Suite 204
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