[Paraview] RequestData Being Called Multiple Times [PV3.1.0]

[Kent Eschenberg]

Using vtkStructuredGrid instead of vtkAlgorithm is, I think, a bad idea 
as only the later supports the latest update mechanism.

I also wrote a reader that produces structured data. I set the extent as 
you have done but don't perform the first two "Set"s. Instead I set the 
origin and spacing in the output data structure.

Kent
Pittsburgh Supercomputing Center

Mike Jackson wrote:
> After looking at this all day today, I the big difference is:
> 
> If I include the following code:
> 
>   outInfo->Set( vtkDataObject::ORIGIN(), DataOrigin, 3 );
>   outInfo->Set( vtkDataObject::SPACING(), DataSpacing, 3 );
> 
>   this->DataExtent[0] = this->DataExtent[2] = this->DataExtent[4] = 0;
>   this->DataExtent[1] = xDim;
>   this->DataExtent[3] = yDim;
>   this->DataExtent[5] = zDim;
>   outInfo->Set( vtkStreamingDemandDrivenPipeline::WHOLE_EXTENT(), 
> DataExtent, 6 );
> 
> Then after each call to RequestData, a call to SetAbortExecute (0) is 
> called which I think is causing an update to occur. If I leave the above 
> code out, then only GetAbortExecute() is called, which is fine as it 
> does not monkey with the ModifiedTime.
> 
> Now I would be more than happy to leave out the above code, but doing so 
> leaves the resulting vtkImageData object not quite "right", ie, It will 
> show an outline in paraview, but nothing else. Maybe someone can fill me 
> in on what is going on.
> 
> I am thinking of maybe trying to inherit from vtkStructuredGrid instead. 
> Our data is just a regular array of Voxels with some extra scalar and 
> vector attributes on them.
> 
> I do not have this problem with a vtkPolyDataAlgorithm..
> 
> 
> --Mike Jackson   Senior Research Engineer
> Innovative Management & Technology Services