the IDs are not generated randomly. They do have a logic in that when a surface is created it elements are increasing. The problem is that you don't know the order that gmsh does its calculation. But it is difficult. I found that a geometrical type of filtering can give good results.
2017-12-13 20:20 GMT+02:00 Shamsul Arefin <[email protected]>: > Hi Andrew, > > Thanks for the link ... > > I want to do the 'naming task' in the batch. Problem is, after the > generation of the volume, the surface IDs are created randomly. In GUI this > is not a problem, but since I am in batch mode, i need a rather stable > solution to do this generation and naming repeatedly. > > > > > Regards, > Shamsul Arefin > ph: 017655441319 > > On Wed 13 Dec 6:53:50 pm, andrew <[email protected]> wrote: > I am glad it helped a bit. > > For extrusion hints you can see the tutorial of openfoam and gmsh > https://openfoamwiki.net/index.php/2D_Mesh_Tutorial_using_GMSH > It gives some info for the extrusion vectors. > > If you change the function in my files you can create functions for a few > elementary geometrical entities. Unfortunately selecting elements according > to geometry is a bit tricky in gmsh. > You can get the elements in an array and sweep in the array. This way you > can select the elements according to their coordinates with any criteria > you like. > > For example in my file it goes > > For PlaneFilter_jj In {0:#PlaneFilter_Surfaces[]-1} <------- > SWEEP SURFACES > PlaneFilter_n[]=PointsOf{Surface{PlaneFilter_Surfaces[PlaneFilter_jj]};}; > <----------- GET ALL POINTS OF SURFACE > PlaneFilter_nn=#PlaneFilter_n[]; > PlaneFilter_cc=0; > For PlaneFilter_kk In {0:#PlaneFilter_n[]-1} <--------- SWEEP > POINTS IN SURFACE > PlaneFilter_pn[]=Point{PlaneFilter_n[PlaneFilter_kk]}; > PlaneFilter_px=PlaneFilter_pn[0]; <------- COORDINATES > PlaneFilter_py=PlaneFilter_pn[1]; > PlaneFilter_pz=PlaneFilter_pn[2]; > ....... > > the two nested loops are for getting the points and their coordinates. > After that you can filter them any way you like... > > > > > 2017-12-13 16:40 GMT+02:00 Shamsul Arefin <[email protected]>: > >> This is a nice trick. Thanks Andrew. >> >> However, this is only for selecting plane surfaces. I may have to tweak >> the code for Cylindrical Surfaces and also for more control over the shape >> of the geometry. >> >> # It would have been better if I could know how entities are stored in an >> array. Say I extrude a surface to create a block. If this extrusion command >> is saved in an array, what would be the sequence of IDs in the array, of >> generated surfaces of the block. >> >> >> Regards, >> Shamsul Arefin >> ph: 017655441319 >> >> On Tue 12 Dec 3:46:59 pm, andrew <[email protected]> wrote: >> I thought it was together with the other files ! >> >> >> >> 2017-12-12 11:43 GMT+02:00 Shamsul Arefin <[email protected]>: >> >>> Is there no other selection by location option? Say I want to select the >>> areas at 'z=0', or volumes between -10<x<+10 and -10<y<+10. >>> >>> The purpose is to select nodes from a particular geometric entity and >>> define name for those nodes i.e. a nodal set. >>> >>> Usually when I know the ID of a surface (for example), i can define a >>> "physical surface" and get the nodes and elements in the output-file >>> grouped together. Problem is, I would not know surface ID's while working >>> in the batch. >>> >>> Or anyone has a better idea for doing this with gmsh? >>> >>> >>> Regards, >>> Shamsul Arefin >>> ph: 017655441319 >>> >>> On Mon 11 Dec 8:26:36 pm, andrew <[email protected]> wrote: >>> perhaps this could help you. It selects a face that belongs to a plane >>> >>> >>> >>> >>> 2017-12-11 18:28 GMT+02:00 Shamsul Arefin <[email protected]>: >>> >>>> Hello, >>>> >>>> Lets say I have a box modeled in gmsh. I want to select different faces >>>> of the box just by - selection through location coordinate. So far have not >>>> find anything in the documentation! Can anyone help? >>>> >>>> >>>> Regards, >>>> Shamsul Arefin >>>> ph: 017655441319 >>>> >>>> _______________________________________________ >>>> gmsh mailing list >>>> [email protected] >>>> http://onelab.info/mailman/listinfo/gmsh >>>> >>>> >>> >>> _______________________________________________ >>> gmsh mailing list >>> [email protected] >>> http://onelab.info/mailman/listinfo/gmsh >>> >>> >> >
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