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<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'>I’ve got one quick follow up to this. If I get the
coordinate of a CellId, such as returned by a vtkCellPicker, which happens to
be an image, is the returned coordinate the center of the voxel or a
corner? If it’s a corner, which one?<o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'><o:p> </o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'>Thanks<o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'><o:p> </o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'> --
Scott<o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'><o:p> </o:p></span></p>
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<div style='border:none;border-top:solid #B5C4DF 1.0pt;padding:3.0pt 0in 0in 0in'>
<p class=MsoNormal><b><span style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'>From:</span></b><span
style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'>
vtkusers-bounces@vtk.org [mailto:vtkusers-bounces@vtk.org] <b>On Behalf Of </b>Scott
Johnson<br>
<b>Sent:</b> Monday, April 05, 2010 3:47 PM<br>
<b>To:</b> Darshan Pai<br>
<b>Cc:</b> vtkusers@vtk.org<br>
<b>Subject:</b> Re: [vtkusers] vtk Coordinate system clarification<o:p></o:p></span></p>
</div>
</div>
<p class=MsoNormal><o:p> </o:p></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'>Thanks Darshan.<o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'><o:p> </o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'>
-- Scott<o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'><o:p> </o:p></span></p>
<div style='border:none;border-top:solid #B5C4DF 1.0pt;padding:3.0pt 0in 0in 0in'>
<p class=MsoNormal><b><span style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'>From:</span></b><span
style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'> Darshan Pai
[mailto:darshanpai@gmail.com] <br>
<b>Sent:</b> Monday, April 05, 2010 3:36 PM<br>
<b>To:</b> Scott Johnson<br>
<b>Cc:</b> vtkusers@vtk.org<br>
<b>Subject:</b> Re: [vtkusers] vtk Coordinate system clarification<o:p></o:p></span></p>
</div>
<p class=MsoNormal><o:p> </o:p></p>
<p class=MsoNormal style='margin-bottom:12.0pt'>All visualization should be in
WorldCoordinate space <o:p></o:p></p>
<div>
<p class=MsoNormal>On Mon, Apr 5, 2010 at 4:29 PM, Scott Johnson <<a
href="mailto:Scott.Johnson@neuwave.com">Scott.Johnson@neuwave.com</a>>
wrote:<o:p></o:p></p>
<div>
<div>
<p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'>Hi
Folks,<o:p></o:p></p>
<p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'> <o:p></o:p></p>
<p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'>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 style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'> <o:p></o:p></p>
<p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'>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 style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'> <o:p></o:p></p>
<p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'>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 style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'> <o:p></o:p></p>
<p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'>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 style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'> <o:p></o:p></p>
<p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'>Thanks<o:p></o:p></p>
<p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'> <o:p></o:p></p>
<p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><span
style='color:#888888'>
-- Scott<o:p></o:p></span></p>
</div>
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