[Paraview] Problem with Custom ParaView Reader

[Andy Bauer]

Hi Kalin,

I think the issue is that your extents are wrong. The extents should be the
index of the first and last point in each logical direction so it should be
[0, 15, 0, 15, 0, 15] if you have a square grid with 4096 points. Note that
this is the whole extent that the reader could provide even though
subsequent filters may ask for a reduced extent. Also, in RequestData() you
should get the requested extent with something like the following and take
out the SetDimension() call:

  vtkInformation *outInfo = outputVector->GetInformationObject(outputPort);
  int subext[6];
  outInfo->Get(vtkStreamingDemandDrivenPipeline::UPDATE_EXTENT(),subext);
  image->SetExtent(subext);

Then use the subextent to fill in your scalars array since it may be less
than what it could potentially provide (e.g. why read in all data when you
only need a subset of that).

I've filled in the vtkJHTDBReader.cxx code with some comments and changes.
You should go through and review what I did since I can't test your code.

Regards,
Andy



On Wed, Feb 12, 2014 at 1:47 PM, Kalin Kanov <kalin at cs.jhu.edu> wrote:

> Hi Andy,
>
> Thanks for the quick response. I am setting the extent to be
> [0,16,0,16,0,16], as follows:
>
> in the constructor:
>         this->extent[0] = 0;
>         this->extent[1] = 16;
>         this->extent[2] = 0;
>         this->extent[3] = 16;
>         this->extent[4] = 0;
>         this->extent[5] = 16;
>
> in RequestInformation():
>         outInfo->Set(
>                 vtkStreamingDemandDrivenPipeline::
>                 WHOLE_EXTENT(),
>                 this->extent, 6);
>
> Attached is the .vti file and the code. In the test harness I also have a
> vtkRenderer, which also displays the data as a 3d cube.
>
>
>
>
> On 12.2.2014 г. 13:30, Andy Bauer wrote:
>
>> Hi Kalin,
>>
>> I'm thinking that maybe there is ghost level information that is wrong,
>> or maybe extent information. I'm assuming that you're running the server
>> in serial so in that case you shouldn't have any ghost levels. If your
>> grid has 16 points in each direction than than the extent for that
>> should be [i, i+15, j, j+15, k, k+15] for a single process (note that
>> extents don't need to start from 0 but usually do). If your grid is 16
>> cells in each direction than the extent would be [i, i+16, j, j+16, k,
>> k+16].
>>
>> If that isn't the problem, dan you share your code and your vti file
>> from your test harness?
>>
>> Regards,
>> Andy
>>
>>
>> On Wed, Feb 12, 2014 at 1:11 PM, Kalin Kanov <kalin at cs.jhu.edu
>> <mailto:kalin at cs.jhu.edu>> wrote:
>>
>>     Dear All,
>>
>>     I am developing a custom ParaView reader for my data. I have a
>>     working plugin for ParaView that reads and displays the data.
>>     However, what I am getting in the 3D view is not as expected. My
>>     reader subclasses vtkImageAlgorithm and produces a 3D structured
>>     grid. When I load the data in ParaView I only see 3 of the surfaces
>>     of the cube (attached is a screenshot). Any idea why this would be
>>     happening?
>>
>>     When I view the data in spreadsheet form all 4096 point (the testing
>>     cube is 16x16x16) have associated scalar data and the coordinates
>>     look good, but the 3D view displays only the left, right and bottom
>>     walls of the cube. Additionally, I also have a small test harness
>>     that uses my custom reader as input for a vtkXMLImageDataWriter and
>>     the resulting .vti file when loaded into ParaView and visualized
>>     looks good.
>>
>>     Thank you,
>>     Kalin Kanov
>>
>>
>>
>
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