[vtkusers] VOI volume rendered is offset to origin?

[dean.inglis at on.aibn.com]

try using a vtkChangeInformation:

<snip>
vtkExtractVOI VOI1
   VOI1 SetInput [reader GetOutput]
   VOI1 SetVOI $xmin $xmax $ymin $ymax $zmin $zmax

set spacing [[VOI1 GetOutput] GetSpacing]
set sx [lindex $spacing 0]
set sy [lindex $spacing 1]
set sz [lindex $spacing 2]

set origin [[VOI1 GetOutput] GetOrigin]
set ox [expr [lindex $origin 0] + $xmin * $sx]
set oy [expr [lindex $origin 1] + $ymin * $sy]
set oz [expr [lindex $origin 2] + $zmin * $sz]

vtkImageChangeInformation VOI
  VOI SetOutputOrigin $ox $oy $oz
  VOI SetInput [VOI1 GetOutput]

vtkOutlineFilter VOIout
  VOIout SetInput [VOI1 GetOutput]

...

vtkContourFilter iso
  iso SetInput [VOI1 GetOutput]

...

vtkVolumeRayCastMapper volumeMapper
    volumeMapper SetVolumeRayCastFunction compositeFunction
    volumeMapper SetInput [VOI GetOutput]

<snip>

Dean