[vtkusers] voxel values in vtkImageData

[Sean McInerney]

First, please read this message with an appropriately stoned-sounding 
voice in mind. Okay, ready?

It's all in your head mannnnnnnnnnnnnn.

I know voxels (volume pixels for the uninitiated) represent a volume in 
space. This, however, is the unreal world and whatever they represent is 
secondary to the fact that they are quanta ... discrete point samples 
... atomic. Therefore, all of the imaging operations that may be applied 
to voxels work with VTK's current implementation. Suppose that your 
image volume were to be represented by n+1 vertices in any dimension and 
the values held in cell attributes rather than point attributes ... all 
image processing would have to proceed as if they where discreet values 
of the center of each cell ... i.e. treating them like point values.

dooooooooooooooooood! Pass the ......

Though we live in a world that seems infinitely divisible, image 
operations are efficient in that they essentially deal with discreet and 
regular point samples. The place where I can see your point having some 
potential impact is this: should the origin exist at (0, 0, 0) or 
shifted half a voxel size in each dimension.

BTW, this is a perennial question ... mannnnnnnnnn.

-Sean