[vtkusers] Negative spacing. Is that going to get me into trouble?

[John Drescher]

I have a set of CT data where I need to load the images by ImageNumber
instead of the default by PatientPosition. As a result the volume is
loaded with increasing image z axis mapping to a decreasing world z
axis. Loading the series with itk does not set the Direction or the
Spacing of the z axes to be negative so I am setting it myself.

I emailed the list a few months back about bad world coordinates:
http://www.nabble.com/Transforming-image-to-world-coordinates-with-negative-z-axis-td22453066.html

Initially I tried to fix this by setting the direction of the z axes
to be -1 but it appears that vtk does not handle that however it
appears that negative spacing in vtk is quite fine. With -2.5 for my z
spacing instead of 2.5 the views are not upside down.

-- 
John M. Drescher