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<DIV><FONT size=2>Hello,every vtkusers:</FONT></DIV>
<DIV><FONT size=2></FONT> </DIV>
<DIV><FONT size=2>I'm writting a program that can remove ROI from a 3D volume.I
prepared to use </FONT></DIV>
<DIV><FONT size=2></FONT> </DIV>
<DIV><FONT size=2>a </FONT><FONT size=2>vtkImageTracerWidget to implement this
function.I use vtkImageTracerWidget</FONT></DIV>
<DIV><FONT size=2></FONT> </DIV>
<DIV><FONT size=2>like this:</FONT></DIV>
<DIV><FONT size=2></FONT> </DIV>
<DIV><FONT size=2> tracerWidget =
vtkImageTracerWidget::New();</FONT></DIV>
<DIV><FONT size=2> //aRenderer is the point of
vtkRenderer<BR> tracerWidget->SetDefaultRenderer(aRenderer);<BR> tracerWidget->SetCaptureRadius(1.5);<BR> tracerWidget->GetGlyphSource()->SetColor(1,
0,
0);<BR> tracerWidget->GetGlyphSource()->SetScale(3.0);<BR> tracerWidget->SetGlyphAngle(45.0);<BR> tracerWidget->GetGlyphSource()->Modified();</FONT></DIV>
<DIV><FONT size=2> //I want to draw always on the plane
paralleled with screen</FONT><FONT
size=2><BR> tracerWidget->ProjectToPlaneOff();</FONT></DIV>
<DIV><FONT size=2> //I don't know why the following sentence must be
added </FONT></DIV>
<DIV><FONT size=2> //and how it
works<BR> tracerWidget->SetProjectionNormalToZAxes();<BR> //volume
is the point of vtkVolume</FONT></DIV>
<DIV><FONT size=2> tracerWidget->SetProp(volume);</FONT></DIV>
<DIV><FONT size=2> //vtkData is the original 3D image
data<BR> tracerWidget->SetInput(vtkData);<BR> tracerWidget->SetInteractor(iren);<BR> tracerWidget->SnapToImageOn();<BR> tracerWidget->AutoCloseOn();<BR> tracerWidget->On();</FONT></DIV>
<DIV><FONT size=2></FONT> </DIV>
<DIV><FONT size=2>But when program runs,the lines and polygons I draw always
stay in the interior </FONT></DIV>
<DIV><FONT size=2></FONT> </DIV>
<DIV><FONT size=2>of the volume.This problem doesn't disappear even I invoke
</FONT></DIV>
<DIV><FONT size=2></FONT> </DIV>
<DIV><FONT size=2>"</FONT><FONT
size=2>tracerWidget->SetProjectionPosition()".</FONT></DIV>
<DIV><FONT size=2></FONT> </DIV>
<DIV><FONT size=2>Can anyone tell me how to draw always on the surface of the 3D
volume?</FONT></DIV></BODY></HTML>