> On 8 Jul 2020, at 12:46, Bojan Niceno <bojan.niceno.scient...@gmail.com> > wrote: > > Dear all, > > I have a problem when trying to mesh planar structured surfaces. Although > points seem to be uniformly placed on a transfinite surface, they move a bit > when recombining the mesh to change triangles to quadrilateral cells. > > Here is a simple script which demonstrates it: > > // Define points > Point(1) = {0.0, 0.0, 0.0}; > Point(2) = {0.5, 0.0, 0.0}; > Point(3) = {0.0, 0.5, 0.0}; > Point(4) = {0.7, 0.0, 0.0}; > Point(5) = {0.0, 0.7, 0.0}; > > // Define connectors from points ... > Line (1) = {2, 4}; > Circle(2) = {4, 1, 5}; > Line (3) = {5, 3}; > Circle(4) = {3, 1, 2}; > > // ... and set them as transfinite > Transfinite Curve {1, 2, 3, 4} = 11 Using Progression 1; > > // Define surface ... > Curve Loop(1) = {1, 2, 3, 4}; Plane Surface(1) = {1}; > > // ... and set it as transfinite too > Transfinite Surface {1}; > > So, as I said, generating a 2D mesh over the surface places points properly, > but command recombine moves them a bit :-/ Is there a way to prevent these > movements of points? > > I am also attaching a screenshot of a mesh before and after recombination, to > illustrate my problem better. >
Indeed, recombination a posteriori applies some smoothing. You should add Recombine Surface{1}; after "Transfinite Surface {1};", which will directly create a quad mesh. Christophe > Best regards, > > Bojan > > P.S. I am not sure if attachments go to the mailing list, I've never used a > mailing list before. > > <points_after_generation.png><points_after_recombination.png>_______________________________________________ > 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