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</o:shapelayout></xml><![endif]--></head><body lang=EN-US link=blue vlink=purple><div class=WordSection1><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Thanks for the suggestion and apologies for the delay, David. Are you sure that a tolerance of 0.5 should be enough? Wouldn’t a lower end contour intersecting a pixel .75 of the way across still be missed with 0.5, since {floor(.75 - .5) + 1} is 1?<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'>I tried tolerance values of 0.5 and 1.0 but unfortunately got the infamous streaking artifacts with both, so now I’m keeping the default tolerance and instead piping the output stencil image data through vtkImageContinuousDilate3D with a kernel size of (3,3,1). That seems to give me the coverage I’m looking for without any artifacts.<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 again,<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Bryan<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><b><span style='font-size:11.0pt;font-family:"Calibri","sans-serif"'>From:</span></b><span style='font-size:11.0pt;font-family:"Calibri","sans-serif"'> David Gobbi [mailto:david.gobbi@gmail.com] <br><b>Sent:</b> Wednesday, July 2, 2014 4:17 PM<br><b>To:</b> Bryan Cool<br><b>Cc:</b> VTK Users<br><b>Subject:</b> Re: [vtkusers] Inclusiveness of Rasterization<o:p></o:p></span></p><p class=MsoNormal><o:p> </o:p></p><div><p class=MsoNormal>Have you tried adjusting the Tolerance on vtkPolyDataToImageStencil?<o:p></o:p></p><div><p class=MsoNormal>You can try setting it to a large value like 0.5, which gives half a pixel<o:p></o:p></p></div><div><p class=MsoNormal>in tolerance. That should guarantee that the contour is fully inside of<o:p></o:p></p></div><div><p class=MsoNormal>the result.<o:p></o:p></p></div><div><p class=MsoNormal><o:p> </o:p></p></div><div><p class=MsoNormal> David<o:p></o:p></p><div><p class=MsoNormal style='margin-bottom:12.0pt'><o:p> </o:p></p><div><p class=MsoNormal>On Wed, Jul 2, 2014 at 2:46 PM, Bryan Cool <<a href="mailto:bryan@radialogica.com" target="_blank">bryan@radialogica.com</a>> wrote:<o:p></o:p></p><blockquote style='border:none;border-left:solid #CCCCCC 1.0pt;padding:0in 0in 0in 6.0pt;margin-left:4.8pt;margin-right:0in'><div><div><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Thanks for the quick reply, David. You’re right: I’m in need of inclusivity on both ends. I’m voxelizing contours using vtkPolyDataToImageStencil and I want to ensure that the resulting stencil fully encapsulates the contours. Are there any tricks to compensate that wouldn’t require me to modify my points directly? I guess I could just dilate my result, but it would be nice to have it as tight around the contours as possible.</span><o:p></o:p></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'> </span><o:p></o:p></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Thanks,</span><o:p></o:p></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Bryan</span><o:p></o:p></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'> </span><o:p></o:p></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><b><span style='font-size:11.0pt;font-family:"Calibri","sans-serif"'>From:</span></b><span style='font-size:11.0pt;font-family:"Calibri","sans-serif"'> David Gobbi [mailto:<a href="mailto:david.gobbi@gmail.com" target="_blank">david.gobbi@gmail.com</a>] <br><b>Sent:</b> Wednesday, July 2, 2014 2:50 PM<br><b>To:</b> Bryan Cool<br><b>Cc:</b> VTK Users<br><b>Subject:</b> Re: [vtkusers] Inclusiveness of Rasterization</span><o:p></o:p></p><div><div><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'> <o:p></o:p></p><div><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'>Hi Bryan,<o:p></o:p></p><div><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'> <o:p></o:p></p></div><div><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'>Do you mean inclusive on both ends? Exclusive on both ends would<o:p></o:p></p></div><div><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'>just make it worse...<o:p></o:p></p></div><div><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'> <o:p></o:p></p></div><div><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'>The behavior of the rasterization is 100% intentional. In order for<o:p></o:p></p></div><div><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'>rasterization to work when there are adjacent areas that are being<o:p></o:p></p></div><div><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'>rasterized, it must be exclusive on one end and inclusive on the<o:p></o:p></p></div><div><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'>other end. Otherwise, adjacent areas could end up with either a<o:p></o:p></p></div><div><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'>gap between them or with an overlap.<o:p></o:p></p></div><div><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'> <o:p></o:p></p></div><div><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'>The exclusitivity can be compensated for by subtracting a small<o:p></o:p></p></div><div><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'>tolerance at the lower end or by using other tricks.<o:p></o:p></p></div><div><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'> <o:p></o:p></p></div><div><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'>What is your use case?<o:p></o:p></p></div><div><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'> <o:p></o:p></p></div><div><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'> - David<o:p></o:p></p></div><div><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'> <o:p></o:p></p></div><div><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'> <o:p></o:p></p><div><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'>On Wed, Jul 2, 2014 at 1:18 PM, Bryan Cool <<a href="mailto:bryan@radialogica.com" target="_blank">bryan@radialogica.com</a>> wrote:<o:p></o:p></p><blockquote style='border:none;border-left:solid #CCCCCC 1.0pt;padding:0in 0in 0in 6.0pt;margin-left:4.8pt;margin-top:5.0pt;margin-right:0in;margin-bottom:5.0pt'><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'>Hi everyone,<br><br>I noticed that vtkImageStencilRaster has code like the following in<br>InsertLine and FillStencilData, for both the x and y directions:<br><br>if (x1 >= xmin)<br> {<br> r1 = vtkMath::Floor(x1) + 1;<br> }<br>if (x2 < xmax)<br> {<br> r2 = vtkMath::Floor(x2);<br> }<br><br>Correct me if I'm wrong, but it looks like the lower side is exclusive,<br>while the upper end is inclusive. The upshot of this is that the only way<br>to stencil the first pixel is to have a line intersect the row on the<br>negative side of the first pixel (in the extents). On the other hand, to<br>stencil the last pixel a line only need intersect anywhere past the<br>second-to-last pixel (in the extents).<br><br>Assuming that's true, it seems a bit asymmetric. Is there any way to have<br>exclusive behavior on both ends?<br><br>Thanks,<br>Bryan<o:p></o:p></p></blockquote></div></div></div></div></div></div></div></blockquote></div><p class=MsoNormal><o:p> </o:p></p></div></div></div></div></body></html>