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<p class=MsoNormal><span lang=EN-US>Hi all,<o:p></o:p></span></p>
<p class=MsoNormal><span lang=EN-US><o:p> </o:p></span></p>
<p class=MsoNormal><span lang=EN-US>I meet the following question:<o:p></o:p></span></p>
<p class=MsoNormal><span lang=EN-US>I get the normal of the plane and a point on
the plane.<o:p></o:p></span></p>
<p class=MsoNormal><span lang=EN-US><o:p> </o:p></span></p>
<p class=MsoNormal><span lang=EN-US>vtkPlaneSource plane = vtkPlaneSource::New();<o:p></o:p></span></p>
<p class=MsoNormal><span lang=EN-US>plane->SetCenter(pointposition);<o:p></o:p></span></p>
<p class=MsoNormal><span lang=EN-US>plane->SetNormal(normal); <o:p></o:p></span></p>
<p class=MsoNormal><span lang=EN-US><o:p> </o:p></span></p>
<p class=MsoNormal><span lang=EN-US>The position of plane is what I expected.<o:p></o:p></span></p>
<p class=MsoNormal><span lang=EN-US><o:p> </o:p></span></p>
<p class=MsoNormal><span lang=EN-US>Then I use myPlane to cut polydata. But
after cutting, it seems that the myPlane is parallel to plane, but its position
is not what I expect.<o:p></o:p></span></p>
<p class=MsoNormal><span lang=EN-US><o:p> </o:p></span></p>
<p class=MsoNormal><span lang=EN-US>vtkPlane *myPlane = vtkPlane::New();<o:p></o:p></span></p>
<p class=MsoNormal><span lang=EN-US>myPlane->setOrigin(pointposition);<o:p></o:p></span></p>
<p class=MsoNormal><span lang=EN-US>myPlane->setNormal(normal);<o:p></o:p></span></p>
<p class=MsoNormal><span lang=EN-US><o:p> </o:p></span></p>
<p class=MsoNormal><span lang=EN-US>The only difference between these two
setting is SetCenter and SetOrigin<o:p></o:p></span></p>
<p class=MsoNormal><span lang=EN-US><o:p> </o:p></span></p>
<p class=MsoNormal><span lang=EN-US>In the vtk document, <o:p></o:p></span></p>
<p class=MsoNormal><span lang=EN-US>vtkPlane->SetOrigin : Set point through
which plane passes.<o:p></o:p></span></p>
<p class=MsoNormal><span lang=EN-US>vtkPlaneSource->SetCenter: Set the
center of the plane<o:p></o:p></span></p>
<p class=MsoNormal><span lang=EN-US><o:p> </o:p></span></p>
<p class=MsoNormal><span lang=EN-US>To define a plane, just need normal and a
point at the plane. From the document, I think these two functions are same.
They just set a point position.<o:p></o:p></span></p>
<p class=MsoNormal><span lang=EN-US> <o:p></o:p></span></p>
<p class=MsoNormal><span lang=EN-US>So why myPlane is not at the position where
plane stays?<o:p></o:p></span></p>
<p class=MsoNormal><span lang=EN-US>Is my understanding wrong or other reasons?<o:p></o:p></span></p>
<p class=MsoNormal><span lang=EN-US><o:p> </o:p></span></p>
<p class=MsoNormal><span lang=EN-US>Thanks for any help!!<o:p></o:p></span></p>
<p class=MsoNormal><span lang=EN-US><o:p> </o:p></span></p>
<p class=MsoNormal><span lang=EN-US>___________________________________________<o:p></o:p></span></p>
<p class=MsoNormal><span lang=EN-US>Yongqiang<o:p></o:p></span></p>
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