[vtk-developers] Proposed filter name and class hierarchy changes

[David E DeMarle]

Hello,

It is because when you take a generic subset out of a structured data
type the output geometry is not necessarily going to stay structured.
Taking just the voxels with a particular range of values out of an
image data can create a blob of voxels that does not completely cover
any cubical volume for instance. Thus the output type has to be
unstructured grid, which can represent any shape.

I am considering giving all of the new vtkExtractSelected* filters a
"PassThrough" which will preserve the input data type and just add new
attribute arrays. vtkFrustumExtractor has this now.

thanks,
Dave DeMarle