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<p class=MsoNormal>Hi Folks,<o:p></o:p></p>
<p class=MsoNormal><o:p> </o:p></p>
<p class=MsoNormal>I’m running into issues trying to spatially coordinate
the display of images and polygons (spheres in this case). My ultimate
goal is to express all coordinates in the DICOM Frame of Reference.<o:p></o:p></p>
<p class=MsoNormal><o:p> </o:p></p>
<p class=MsoNormal>Right now I’m trying to display axial, sagittal, and
coronal slices and the intersection of those image planes with spheres. I’m
using vtkImageReslice to slice the images, and vtkCutter to extract the
contours of the intersection, but am running into problems getting the sliced
polygons to show up in the right place with respect to the images. I can
get the spheres to display in the correct location in a MIP rendering.<o:p></o:p></p>
<p class=MsoNormal><o:p> </o:p></p>
<p class=MsoNormal>My difficulty is understanding in what coordinate system
everything but images are expressed in. (I’ve read the Coordinate
System section in the new version of the VTK User’s guide.) For
example, if I set the position of a vtkSphereSource with SetCenter is that in
pixel coordinates in the coordinate system, or is it an absolute location in
space? The same goes for a vtkPlane: What coordinate system should
locations passed to SetOrigin be in?<o:p></o:p></p>
<p class=MsoNormal><o:p> </o:p></p>
<p class=MsoNormal>My thought was that everything was expressed in the World
coordinate system and the world coordinate system was established by the images,
but that doesn’t seem to be working for me.<o:p></o:p></p>
<p class=MsoNormal><o:p> </o:p></p>
<p class=MsoNormal>Thanks<o:p></o:p></p>
<p class=MsoNormal><o:p> </o:p></p>
<p class=MsoNormal> --
Scott<o:p></o:p></p>
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