# [Gmsh] 3D meshing won't work

**Christophe Geuzaine**
geuzaine at acm.caltech.edu

*Wed May 5 06:13:28 CEST 2004*

Magdalena Stolarska wrote:
>* Hi. I have a few of questions. I apologize if they are elementary --
*>* I'm fairly new to this and have a hard time finding an explanation on the
*>* web.
*>*
*>* 1) What exactly is consistent elementary surface orientation (as described
*>* under the Surface Loop explanation in the documentation of Gmsh 1.51)?
*>*
*>* 2) I've attached the *.geo file that I am working on -- For some reason,
*>* the 2D surface meshing works okay, but the 3d meshing is not working (I
*>* just end up with a 2d mesh). Depending on what I choose the
*>* characteristic length to be, I get a variety of complaints. For example,
*>* for a characteristic length of 0.1, I get no complaints other than one
*>* error: "Error : No contour". For a characteristic length of 0.05 I get
*>* complaints like (in addition to the one above)
*>* Error : Missing edge without any intersection (0.55,0.1,0.3) (0.55,0,0.3)
*>* and
*>* Warning : *Unrecoverable* face (0 <--> 1=2*(3-1)-3)
*>* For a characteristic length of 0.04 the only error I get is "Error : No
*>* contour".
*>*
*>>*From the little that I know gmsh, I am thinking that the fact that there
*>* is no 3d mesh has to do with either the surface loop ordering or the
*>* error:"Error : No contour". I checked all of my Line Loops, and the
*>* ordering seems okay, so could you at least please let me know what the no
*>* contour error could mean. Any other suggestions would also be greatly
*>* appreciated. Thank you.
*
The definition of the line loop 74 is wrong:
Line Loop(74) = {22,23,-47,45,48,25,26,27,28};
should be replaced with
Line Loop(74) = {22,23,-47,45,48,25,26,27,28,21};
PS: You should use the graphical user interface to construct your loops:
it makes the whole process soooo much easier...
--
Christophe Geuzaine
Applied and Computational Mathematics, Caltech
geuzaine at acm.caltech.edu - http://geuz.org