[Paraview] Warning: ExtractGrid and MultiGroup Datasets

[John Biddiscombe]

I've noticied this too, - (but not using the ExtractGrid filter). The 
trouble is that a piece of data (only image data, not unstructured) has 
the origin set to the real origin of the whoe data, and each piece has 
the same origin - when extracted, the extent is not the whole extent and 
tada... they go to the same place.

This is a use case where vtkMultiPieceDataSet would be useful as it 
would make it clear to filters like extract grid that this is a piece - 
and not some generic group/block data and something extra needs to be 
done - such as query the container for extra info about orgin offsets etc.

Of course this could be subsumed into multiblock data, but....

JB

> Bug 5808 reported on 9/30/2007 that ExtractGrid puts the extracted 
> piece at the wrong location. I just discovered that when it is used 
> with a 256-part multigroup dataset, where each part is image data, it 
> puts ALL 256 extracted pieces at the same location.
>
> One symptom was that the resultant picture seemed to have NxN points 
> but "Information" said it had 256xNxN points.
>
> I suggest the priority of this bug be raised. ExtractGrid is an 
> important tool for looking at extremely large image datasets but it is 
> currently useless.
>
> Kent
> Pittsburgh Supercomputing Center
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-- 
John Biddiscombe,                            email:biddisco @ cscs.ch
http://www.cscs.ch/about/BJohn.php
CSCS, Swiss National Supercomputing Centre  | Tel:  +41 (91) 610.82.07
Via Cantonale, 6928 Manno, Switzerland      | Fax:  +41 (91) 610.82.82