[Paraview] [EXTERNAL] Re: Volume rendering of structured/regular grid

[Urban Simoncic]

Utkarsh,

thank you for the answer, this works as I would like. So, the trick is 
that reader represents the data with the proper data object, in this 
case the UniformGrid, not the Geometry...

Urban


On 30.10.2013 19:50, Utkarsh Ayachit wrote:
> Urban,
>
> For Analyze files, you have another alternative.
> + Load the AnalyzeNifTIO plugin from Tools | Manage Plugins dialog.
> + Then open the file *.img and choose "Analyze Files (Plugin)" as the reader.
>
> That will open the data as an image dataset that you can volume render directly.
>
> Utkarsh
>
>
> On Wed, Oct 30, 2013 at 10:44 AM, Urban Simoncic
> <urban.simoncic at gmail.com> wrote:
>> My image is a PET image of size 128Ũ128Ũ35, saved in Analyze format. I can
>> open it, but I can't select the representation to be "volume". I can
>> "Tetrahedralize" it, but than the interaction with viewer is terribly slow,
>> obviously because of memory footprint.
>>
>> Does the ParaView have (or should have) algorithm for volume rendering of
>> uniform rectilinear grid? Does the VTK have such algorithms? I thought
>> (although could not understand the rationale behind) that the ParaView has
>> only algorithm for volume rendering of unstructured grid because I am not
>> able to do volume rendering on any of my medical images and because I found
>> this paper: http://www.sandia.gov/~kmorel/documents/ParallelVolRen.pdf
>>
>> Thanks,
>> Urban
>>
>>
>> On 30.10.2013 15:32, Moreland, Kenneth wrote:
>>> Actually, you shouldn't even have to do that. You should be able to just
>>> change the representation to volume. If your data is a uniform rectilinear
>>> grid (the information panel declares the type as Image (Uniform
>>> Rectilinear Grid)), then it will be directly volume rendered using an
>>> image-based volume renderer. If your data is curvilinear (the information
>>> panel declares the type as Structured (Curvilinear) Grid), then ParaView
>>> will internally run tetrahedralize under the covers and use an
>>> unstructured volume rendering algorithm. As Utkarsh said, though, this
>>> will increase the memory footprint.
>>>
>>> -Ken
>>>
>>>
>>>
>>>
>>> On 10/30/13 8:24 AM, "Utkarsh Ayachit" <utkarsh.ayachit at kitware.com>
>>> wrote:
>>>
>>>> You can convert the structured grid to unstructured grid by apply the
>>>> "Tetrahedralize" filter. Note, however, that this will increase the
>>>> memory footprint quite considerably. So if your structured grid is
>>>> "huge", you may run into memory issues.
>>>>
>>>> Utkarsh
>>>>
>>>> On Wed, Oct 30, 2013 at 10:03 AM, Urban Simoncic
>>>> <urban.simoncic at gmail.com> wrote:
>>>>> It's 4.0.1 64-bit for Win-7, original Kitware build.
>>>>>
>>>>> Thanks,
>>>>> Urban
>>>>>
>>>>>
>>>>> On 30.10.2013 14:53, Utkarsh Ayachit wrote:
>>>>>> What version of ParaView is this?
>>>>>>
>>>>>> On Tue, Oct 29, 2013 at 5:12 PM, Urban Simoncic
>>>>>> <urban.simoncic at gmail.com> wrote:
>>>>>>> Hi,
>>>>>>>
>>>>>>> I would like to do volume rendering on a medical image, which is 3D
>>>>>>> structured/regular grid. I can open the image, display slices etc.,
>>>>>>> but
>>>>>>> can't do volume rendering. To my understanding that's because volume
>>>>>>> rendering works only for unstructured grid. Is that true? Is it
>>>>>>> possible
>>>>>>> to
>>>>>>> convert the structured/regular grid into unstructured one?
>>>>>>>
>>>>>>> Thanks,
>>>>>>> Urban
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