[vtkusers] Volume + surface transparency with OpenGL2

Wed Nov 25 18:30:00 EST 2015

Thanks all for the feedback and use-cases. I have added this to the list of
features and will discuss this with the team members on possible solutions.

Thanks,
Aashish

On Wed, Nov 25, 2015 at 5:21 AM, Simon ESNEAULT <simon.esneault at gmail.com>
wrote:

> Hello,
>
> We also have a need for such a feature, in order to display a virtual
> prosthesis within the patient anatomy.
> We ended up proposing two solutions for our customers :
> - Render a full opaque surface within the volume rendering (
> http://picpaste.com/pics/solution1.1448446727.png)
> - Render a translucent surface on top of the volume rendering using a
> layer system with 2 renderers on the same viewport (
> http://picpaste.com/pics/solution2.1448446818.png)
>
> But neither of the solution are completely satisfying as we would also
> like to blend a translucent mesh in the middle of the volume.
>
> I can provide some data if it can help to develop this feature.
>
> Have a good day,
> Simon
>
> 2015-11-24 2:52 GMT+01:00 Marcus D. Hanwell <marcus.hanwell at kitware.com>:
>
>> We have also had a number of tomviz users ask if this is possible, and
>> they have similar requirements to those stated above. We often have
>> the overall structure rendered as a volume, and are looking at
>> distinct isosurfaces, or in future segmented features, where the ideal
>> would be to offer a translucent surface within the volume.
>>
>> On Mon, Nov 23, 2015 at 7:05 PM, David Cole via vtkusers
>> <vtkusers at vtk.org> wrote:
>> > Me too.
>> >
>> > We want to visualize structures (natural and artificial) inside of
>> volume
>> > renderings of CT scans, mostly of people.
>> >
>> > Works great without using translucent polydata. As soon as you make any
>> of
>> > it translucent, it just sort of disappears all the way... Very confusing
>> > when you first encounter it.
>> >
>> > So... +1. And let me know what I can do to test/help out...
>> >
>> >
>> > David C.
>> >
>> >
>> >
>> > On Monday, November 23, 2015, Xabi Riobe <xabivtk at gmail.com> wrote:
>> >>
>> >> Here are at least 2 examples:
>> >>
>> >> - medical data : the body is voxelized and you have the segmentation of
>> >> organs/bones/vessels
>> >> - material : cement, rock structure voxelized, with segmentation of the
>> >> different layers, components
>> >>
>> >> in both cases you may want to superimpose the surfaces and play with
>> >> transparency to highlight an entity but still seeing the inside of it,
>> >> or you can have tools with polygonal surface that you will insert in an
>> >> easier way into the volume if they are transparent, or just a clipping
>> plane
>> >> that you want to be transparent to place it with precision inside the
>> volume
>> >> before doing the clip...
>> >>
>> >> I'm glad to hear it may fit in a todo list :)
>> >> Let me know if someone starts working on this, i may give any kind of
>> help
>> >> !
>> >>
>> >> Thanks
>> >>
>> >>
>> >> 2015-11-23 21:40 GMT+01:00 Aashish Chaudhary
>> >> <aashish.chaudhary at kitware.com>:
>> >>>
>> >>> On Mon, Nov 23, 2015 at 3:14 PM, Xabi Riobe <xabivtk at gmail.com>
>> wrote:
>> >>>>
>> >>>> Hi Aashish,
>> >>>>
>> >>>> For example, if you render a volume with vtkGPUVolumeRayCastMapper,
>> or
>> >>>> vtkFixedPointVolumeRayCastMapper, and you put inside a sphere
>> rendered with
>> >>>> vtkPolyDataMapper, as soon as you change the sphere actor opacity
>> the depth
>> >>>> notion is lost, with the sphere appearing behind the volume.
>> >>>
>> >>>
>> >>> Thanks for clarification. Yes, this is not currently supported (I am
>> not
>> >>> aware and we don't handle this in the mapper). This is a interesting
>> use
>> >>> case. I will add it to the feature request and will get back to you.
>> Just
>> >>> curious, what would be a real world example use-case you have for this
>> >>> feature? Can you share bit more domain information (medical /
>> scientific
>> >>> etc.).
>> >>>
>> >>> - Aashish
>> >>>
>> >>>
>> >>>
>> >>> --
>> >>> | Aashish Chaudhary
>> >>> | Technical Leader
>> >>> | Kitware Inc.
>> >>> | http://www.kitware.com/company/team/chaudhary.html
>> >>
>> >>
>> >
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>
>
> --
> ------------------------------------------------------------------
> Simon Esneault
> Rennes, France
> ------------------------------------------------------------------
>
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-- 

*| Aashish Chaudhary | Technical Leader         | Kitware Inc.            *
*| http://www.kitware.com/company/team/chaudhary.html
<http://www.kitware.com/company/team/chaudhary.html>*
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