> On 5 Oct 2020, at 07:05, bi...@netc.it wrote: > > Hello. I'm trying to parse a mesh.msh generated by gmsh. > > I work with 9-quad elements. I see in documentation that inside of the > elements, nodes are ordered like this : > > v > ^ > | > 3-------6-------2 > | | | > | | | > 7 8-------5 --> u > | | > | | > 0-------4-------1 > > I made a 2D mesh (all surfaces normals are oriented in the same direction) > > When i look at my 2D mesh (in plan XY) the element 265 : > 265 2 44 1047 533 49 1102 1103 544 1104 > > is oriented like this related to the golbal X and Y axis > > ie, when looking at the screen i see: > 44-------49-------2 > | | | Y > | | | ^ > 1102 1104 544 | > | | | | > | | | | > 1047--1103----533 x------> X > > it seems that u anv v vectors are oriented like this : > 1-----4-----0 > | | | > | | | > u <---5-----8 7 > | | | > | | | > 2-----6-----3 > | > V > v > > > How are V and U vectors defined for each element ?
It depends on the definition of the surface and the meshing algorithm. > Is there a way to orient them along the natural X and Y axis ? With the transfinite algorithm you could force the elements to be generated in a certain order by specifying the interpolation corners. But in general you won't know the correspondance - Gmsh produces unstructured meshes! So you would use the (u,v,w) -> (x,y,z) mapping (through e.g. Lagrange basis functions) to make the connection. Christophe > > Thanks > > > > > _______________________________________________ > gmsh mailing list > gmsh@onelab.info > http://onelab.info/mailman/listinfo/gmsh — Prof. Christophe Geuzaine University of Liege, Electrical Engineering and Computer Science http://www.montefiore.ulg.ac.be/~geuzaine _______________________________________________ gmsh mailing list gmsh@onelab.info http://onelab.info/mailman/listinfo/gmsh