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

[Urban Simoncic]

My image is a PET image of size 128×128×35, 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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