[Paraview] Paraview input data format: CELL_DATA vs POINT_DATA

[Moreland, Kenneth]

Point data are samples of a continuous field. ParaView will interpolate the point data inside cells to estimate this continuous field. 

Cell data are a field integrated over the volume of each cell. These are discrete values for each cell. 

Many filters such as streamlines require a continuous field. Thus, they only work with point data. You can use the Cell Data To Point Data filter to convert a cell field to the point field these filters need. 

The glyph filter is a bit different. The Cell Data To Point Data trick will work fine with that, too. A slightly more accurate representation would be to instead use the Cell Centers filter instead. That trick will only work for the Glyph filter, and you probably won't be able to tell the difference between the two methods. 

-Ken

Sent from my iPad so blame autocorrect.

> On Feb 19, 2015, at 6:06 PM, Canis Major <canismajorwuff at gmail.com> wrote:
> 
> I have a structured grid data, that is why I specify 'DATASET STRUCTURED_GRID' type at the output file.
> I have velocity and pressure as cell  attribute, as a result I write CELL_DATA.
> But when I visualize the data in Paraview I cannot perform for example glyphs or streamlines filters.
> What is the difference in paraview interpretation of CELL_DATA and POINT_DATA?
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