[vtkusers] Volume + surface transparency with OpenGL2

[David Cole]

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
> <javascript:_e(%7B%7D,'cvml','aashish.chaudhary at kitware.com');>>:
>
>> On Mon, Nov 23, 2015 at 3:14 PM, Xabi Riobe <xabivtk at gmail.com
>> <javascript:_e(%7B%7D,'cvml','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
>> <http://www.kitware.com/company/team/chaudhary.html>*
>>
>
>
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