[vtkusers] volume spacing in z direction?

[Mark Wyszomierski]

Hello all,

When rendering a volume from a dataset, what is the proper value to
use for setting the spacing along the z axis? I am using a DICOM
dataset as input, and get the true distance between slices using the
image position patient tags. However the thickness of each image comes
into play in the following three cases:

1) Slice thickness equals distance between slices, this is the easy
one, distance between slices can be used directly, the slices are
touching.

2) Slice thickness is less than the distance between slices, this
means there is a gap between slices. What distance to use for this?

3) Slice thickness is greater than the distance between slices, this
means the slices are overlapping. What distance to use for this?

There is a DICOM tag called Spacing between slices but it isn't
consistent. Any ideas?

Thanks,
Mark