[vtkusers] vtkImageImport -> cell data

[Martin Genet]

Thanks so much, Cory and David! Martin

On 18/01/2016 14:45, David Gobbi wrote:
> Hi Martin,
>
> In VTK, image data is point data, one data value per point.  Cell data 
> isn't used because the vtkVoxel cell is not a voxel in the 
> conventional sense: a vtkVoxel is a finite element that connects 8 
> points, where each corner point generally has a data value (use of 
> point scalars in VTK is much more common than the use of cell 
> scalars).  So the typical usage of vtkVoxel is contrary to the 
> conventional definition of "voxel" which has just one data value.
>
> The VTK image processing filters work on point data, because a VTK 
> point fits the conventional definition of "voxel" (i.e. a voxel 
> defined as one data sample in a volumetric grid of such samples) 
> better than vtkVoxel does.
>
>  - David
>
> On Mon, Jan 18, 2016 at 4:27 AM, Martin Genet 
> <martin.genet at polytechnique.edu 
> <mailto:martin.genet at polytechnique.edu>> wrote:
>
>     Hey everyone,
>
>     I'm realizing that vtkImageImport generates images with point
>     data, not cell data—the Detailed Description says "The array
>     applies on scalar point data only, not on cell data." I was
>     wondering why? I would expect it to read the data as cell data,
>     with one value per voxel. Thanks for helping to understand!
>
>     Martin
>

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