Hi, The Background Field = <field_id> ; command is used to declare that field <field_id> 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 Min field, like in Gmsh tutorial 10<http://gmsh.info/doc/texinfo/gmsh.html#t10_002egeo>. 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.
Faithfully Yours, Guillaume DILASSER Doctorant SACM / LEAS CEA - Centre de Saclay - Bât.123 - PC 319c 91191 Gif sur Yvette Cedex - France - [email protected]<mailto:[email protected]> De : gmsh [mailto:[email protected]] De la part de Prithivirajan V Envoyé : mercredi 26 avril 2017 18:20 À : [email protected] Objet : [Gmsh] Issue with multiple fields ( attractor and thresholds) Dear Gmsh users, 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. Could you help me fix this - am I doing anything wrong ? Also, could you make me understand what precisely the background field does ? An excerpt from the code : Merge "F:\Research\Work\Dream3D_v5.1_wrking\Meshfiles\Grain_1.stl"; Surface Loop(1)={1}; Volume(1)={1}; Physical Volume(1)={1}; Merge "F:\Research\Work\Dream3D_v5.1_wrking\Meshfiles\Grain_2.stl"; Surface Loop(2)={2}; Volume(2)={2}; Physical Volume(2)={2}; Merge "F:\Research\Work\Dream3D_v5.1_wrking\Meshfiles\Grain_3.stl"; Surface Loop(3)={3}; Volume(3)={3}; Physical Volume(3)={3}; Field[1] = Attractor; Field[1].NodesList = {108706}; Field[2] = Threshold; Field[2].IField = 1; Field[2].LcMin = 0.75; Field[2].LcMax = 3; Field[2].DistMin = 15; Field[2].DistMax = 30; Field[3] = Attractor; Field[3].NodesList = {90000,90001,90002,90003}; Field[4] = Threshold; Field[4].IField = 3; Field[4].LcMin = 1.5; Field[4].LcMax = 3; Field[4].DistMin = 3; Field[4].DistMax = 7.5; Background Field = 4; Mesh.CharacteristicLengthExtendFromBoundary = 0; Thanks, Prithvi
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