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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D;mso-fareast-language:EN-US">Hi,<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D;mso-fareast-language:EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D;mso-fareast-language:EN-US">The
<i>Background Field = <field_id> ;</i> command is used to declare that field <i><field_id></i> should be used to set the local mesh size. Therefore, the result you get is perfectly normal : as you set field 4 to be used as background, all refinement information
that should come from field 2 is simply never applied. To combine the effect of fields 2 and 4, use a
<i>Min</i> field, like in Gmsh <a href="http://gmsh.info/doc/texinfo/gmsh.html#t10_002egeo">
tutorial 10</a>. By declaring field 5 that is the minimum of field 2 and 4 and then applying 5 as the background field, you will get the refinement of field 2 and 4 combined.<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D;mso-fareast-language:EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D;mso-fareast-language:EN-US">Faithfully Yours,<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Tahoma",sans-serif;color:#000099">Guillaume DILASSER</span><span style="font-size:10.0pt;font-family:"Tahoma",sans-serif;color:#000099"><o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:7.5pt;font-family:"Arial",sans-serif;color:#000099">Doctorant SACM / LEAS<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:7.5pt;font-family:"Arial",sans-serif;color:#000099">CEA - Centre de Saclay - Bât.123 - PC 319c</span><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#000099"><o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:7.5pt;font-family:"Arial",sans-serif;color:#000099">91191 Gif sur Yvette Cedex - France -</span><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#000099"><o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:7.5pt;font-family:"Arial",sans-serif;color:#000099"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:7.5pt;font-family:"Arial",sans-serif;color:#000099"><a href="mailto:guillaume.dilasser@cea.fr"><span style="color:blue">guillaume.dilasser@cea.fr</span></a><o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D;mso-fareast-language:EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D;mso-fareast-language:EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><b><span style="font-size:11.0pt;font-family:"Calibri",sans-serif">De :</span></b><span style="font-size:11.0pt;font-family:"Calibri",sans-serif"> gmsh [mailto:gmsh-bounces@ace20.montefiore.ulg.ac.be]
<b>De la part de</b> Prithivirajan V<br>
<b>Envoyé :</b> mercredi 26 avril 2017 18:20<br>
<b>À :</b> gmsh@geuz.org<br>
<b>Objet :</b> [Gmsh] Issue with multiple fields ( attractor and thresholds)<o:p></o:p></span></p>
<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">Dear Gmsh users,<br>
<br>
I am trying to create 3D volume mesh from .STL files that I have. In addition, I am trying to refine my 3D mesh locally around known points. I am using 2 sets of attractor /threshold to carry out differential refinements.However, I am not able to carry out
these two simultaneous refinements, I am only getting a refined mesh only at one of the locations.<br>
<br>
<b>Could you help me fix this - am I doing anything wrong ?<br>
<br>
Also, could you make me understand what precisely the background field does ?</b> <o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal"><b>An excerpt from the code : </b><o:p></o:p></p>
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<p class="MsoNormal" style="margin-bottom:12.0pt"><o:p> </o:p></p>
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<p class="MsoNormal">Merge "F:\Research\Work\Dream3D_v5.1_wrking\Meshfiles\Grain_1.stl";<o:p></o:p></p>
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<p class="MsoNormal">Surface Loop(1)={1};<o:p></o:p></p>
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<p class="MsoNormal">Volume(1)={1};<o:p></o:p></p>
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<div>
<p class="MsoNormal">Physical Volume(1)={1};<o:p></o:p></p>
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<p class="MsoNormal">Merge "F:\Research\Work\Dream3D_v5.1_wrking\Meshfiles\Grain_2.stl";<o:p></o:p></p>
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<p class="MsoNormal">Surface Loop(2)={2};<o:p></o:p></p>
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<p class="MsoNormal">Volume(2)={2};<o:p></o:p></p>
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<p class="MsoNormal">Physical Volume(2)={2};<o:p></o:p></p>
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<p class="MsoNormal">Merge "F:\Research\Work\Dream3D_v5.1_wrking\Meshfiles\Grain_3.stl";<o:p></o:p></p>
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<p class="MsoNormal">Surface Loop(3)={3};<o:p></o:p></p>
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<p class="MsoNormal">Volume(3)={3};<o:p></o:p></p>
</div>
<div>
<p class="MsoNormal">Physical Volume(3)={3};<o:p></o:p></p>
</div>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">Field[1] = Attractor;<o:p></o:p></p>
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<div>
<p class="MsoNormal">Field[1].NodesList = {108706};<o:p></o:p></p>
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<p class="MsoNormal">Field[2] = Threshold;<o:p></o:p></p>
</div>
<div>
<p class="MsoNormal">Field[2].IField = 1;<o:p></o:p></p>
</div>
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<p class="MsoNormal">Field[2].LcMin = 0.75;<o:p></o:p></p>
</div>
<div>
<p class="MsoNormal">Field[2].LcMax = 3;<o:p></o:p></p>
</div>
<div>
<p class="MsoNormal">Field[2].DistMin = 15;<o:p></o:p></p>
</div>
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<p class="MsoNormal">Field[2].DistMax = 30;<o:p></o:p></p>
</div>
<div>
<p class="MsoNormal"><o:p> </o:p></p>
</div>
<div>
<p class="MsoNormal">Field[3] = Attractor;<o:p></o:p></p>
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<p class="MsoNormal">Field[3].NodesList = {90000,90001,90002,90003};<o:p></o:p></p>
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<p class="MsoNormal">Field[4] = Threshold;<o:p></o:p></p>
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<p class="MsoNormal">Field[4].IField = 3;<o:p></o:p></p>
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<p class="MsoNormal">Field[4].LcMin = 1.5;<o:p></o:p></p>
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<div>
<p class="MsoNormal">Field[4].LcMax = 3;<o:p></o:p></p>
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<div>
<p class="MsoNormal">Field[4].DistMin = 3;<o:p></o:p></p>
</div>
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<p class="MsoNormal">Field[4].DistMax = 7.5;<o:p></o:p></p>
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<div>
<p class="MsoNormal"><o:p> </o:p></p>
</div>
<div>
<p class="MsoNormal">Background Field = 4;<o:p></o:p></p>
</div>
<div>
<p class="MsoNormal">Mesh.CharacteristicLengthExtendFromBoundary = 0;<o:p></o:p></p>
</div>
</div>
<div>
<p class="MsoNormal"><o:p> </o:p></p>
</div>
<div>
<p class="MsoNormal"><o:p> </o:p></p>
</div>
<div>
<p class="MsoNormal"><o:p> </o:p></p>
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<div>
<p class="MsoNormal">Thanks,<br>
Prithvi<o:p></o:p></p>
</div>
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