<div dir="ltr"><div dir="ltr">Hi Maxime,<div><br></div><div>Thanks for your reminder. I thought I replied to the mailing list as well. I am forwarding our email exchange to the list now. Thanks for your help.</div><div><br></div><div>Best regards,</div><div>Howard</div></div><div><br></div><div>=======================================================</div><div><br></div><div>Hi Howard,<div><br></div><div>I’m glad that it works !</div><div><br></div><div>Please answer to the email list so everyone knows the solution. It is also helpful for people facing the same issue in the future.</div><div><br></div><div>Best regards,</div><div> Maxime Chauvin<br><div><br><blockquote type="cite"><span class="gmail-im" style="color:rgb(80,0,80)"><div>On 8 Jul 2020, at 00:47, Howard <<a href="mailto:lomahu@gmail.com" target="_blank">lomahu@gmail.com</a>> wrote:</div><br></span><div><span class="gmail-im" style="color:rgb(80,0,80)"><div dir="ltr"><div>Hi Maxime,</div><div><br></div><div>You are absolutely right that the wrong normals are the culprit. After that is fixed the mesh surface becomes a solid object indeed. Thank you very much.</div><div><br></div><div>Howard<br></div></div><br></span><div class="gmail_quote"><span class="gmail-im" style="color:rgb(80,0,80)"><div dir="ltr" class="gmail_attr">On Tue, Jul 7, 2020 at 5:41 AM maxime <<a href="mailto:maxime.chauvin@inserm.fr" target="_blank">maxime.chauvin@inserm.fr</a>> wrote:<br></div></span><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div><span class="gmail-im" style="color:rgb(80,0,80)">Dear Howard,<div><br></div><div>I opened your STL with Blender (<a href="https://www.blender.org/" target="_blank">https://www.blender.org</a>) and I can see one problem with your STL:</div><div><ul><li style="margin-left:15px">the normals are not all facing outwards, see attached screenshot.</li></ul></div><div><br></div><div>This means that GATE (Geant4) will not be able to create a closed volume from the STL, </div><div>and therefore this ‘phantom’ will be transparent to X-rays.</div><div><br></div><div>One easy solution is to ask Blender to recalculate the normals outside (Menu Mesh -> Normals -> Recalculate Outside) and then save (File -> export to STL, beware of the coordinates).</div><div><br></div><div>The best is to revise the way you produce your STL so it is correct from the start. And then Blender is just an easy way to check the STL files you create.</div><div><br></div><div>I believe it will now work in GATE.</div><div><br></div><div>Good luck,</div><div> Maxime Chauvin</div><div><br></div></span><div><span id="gmail-m_718701270550453309cid:1732b74e0c298e450631"><Screenshot 2020-07-07 at 11.32.04.png></span><div class="gmail-yj6qo gmail-ajU" style="outline:none;padding:10px 0px;width:22px;margin:2px 0px 0px"><div id="gmail-:p6" class="gmail-ajR" tabindex="0" style="background-color:rgb(232,234,237);border:none;clear:both;line-height:6px;outline:none;width:24px;border-radius:5.5px"><img class="gmail-ajT" src="https://ssl.gstatic.com/ui/v1/icons/mail/images/cleardot.gif" style="background-image: url("https://www.gstatic.com/images/icons/material/system/1x/more_horiz_black_20dp.png"); background-position: 50% 50%; background-size: 20px; background-repeat: no-repeat; background-attachment: initial; background-origin: initial; background-clip: initial; height: 11px; opacity: 0.54; width: 24px;"></div></div></div></div></blockquote></div></div></blockquote></div></div></div><div><br></div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Tue, Jul 7, 2020 at 5:41 AM maxime <<a href="mailto:maxime.chauvin@inserm.fr">maxime.chauvin@inserm.fr</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div style="overflow-wrap: break-word;">Dear Howard,<div><br></div><div>I opened your STL with Blender (<a href="https://www.blender.org" target="_blank">https://www.blender.org</a>) and I can see one problem with your STL:</div><div><ul><li>the normals are not all facing outwards, see attached screenshot.</li></ul></div><div><br></div><div>This means that GATE (Geant4) will not be able to create a closed volume from the STL, </div><div>and therefore this ‘phantom’ will be transparent to X-rays.</div><div><br></div><div>One easy solution is to ask Blender to recalculate the normals outside (Menu Mesh -> Normals -> Recalculate Outside) and then save (File -> export to STL, beware of the coordinates).</div><div><br></div><div>The best is to revise the way you produce your STL so it is correct from the start. And then Blender is just an easy way to check the STL files you create.</div><div><br></div><div>I believe it will now work in GATE.</div><div><br></div><div>Good luck,</div><div> Maxime Chauvin</div><div><br></div><div><img id="gmail-m_5354322676167207358C5D21A89-714F-4A47-B7F6-5FD14092E625" src="cid:1732e89df2398e450631"><br><div><br><blockquote type="cite"><div>On 7 Jul 2020, at 05:35, Howard <<a href="mailto:lomahu@gmail.com" target="_blank">lomahu@gmail.com</a>> wrote:</div><br><div><div dir="ltr"><div>Dear Gate-users,</div><div><br></div><div>Is there anyone out there an expert on the tessellated volume? I generated a tessellated mesh object based on a 3x3 binary matrix:</div><div><br></div><div>0 1 0</div><div>1 1 1</div><div>0 1 0</div><div><br></div><div>where 0 means completely opaque and 1 completely transparent. For some reason when I applied this volume in GATE as a phantom (set materials as Tungsten) for X-ray, there was no beam attenuation. In other words, this volume behaved like an empty shell instead of a solid piece. The STL file for this volume in ASCII format is attached to this email for your reference.</div><div><br></div><div>It would be truly appreciated if any expert on tessellated volume can help out or suggest any software allowing us to look for more detail of the volume? <br></div><div><br></div><div>Howard<br></div></div>
<span id="gmail-m_5354322676167207358cid:f_kcbdogwb0"><ASCIITest3x3.stl></span>_______________________________________________<br>Gate-users mailing list<br><a href="mailto:Gate-users@lists.opengatecollaboration.org" target="_blank">Gate-users@lists.opengatecollaboration.org</a><br><a href="http://lists.opengatecollaboration.org/mailman/listinfo/gate-users" target="_blank">http://lists.opengatecollaboration.org/mailman/listinfo/gate-users</a></div></blockquote></div><br></div></div></blockquote></div></div>