# [Gmsh] coplanar points problem

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

*Wed Oct 6 07:40:05 CEST 2004*

Krishna Mohan Gundu wrote:
>* Dear Christophe Geuzaine,
*>*
*>* I have attached pcf1.geo file. It basically has six "holes" in a
*>* planar slab. Note that, I realize these are not holes by gmsh
*>* definition. I generated this file using a program. First I create a
*>* slab, then subtract the holes one by one from it.
*>*
*>* When I try to mesh it, gmsh gives coplanar points warnings, some other
*>* error and does not generate a mesh. Along the suggestion given in this
*>* forum I reduced the char. length for the hole nodes from 0.10 to 0.05
*>* (pcf2.geo). It again gives me coplanar points warnings and errors like
*>*
*>* Info : 1/6: Edge 3082->1942 => 0 division(s)
*>* Error : Missing edge without any intersection (0.573162,0.190714,0)
*>* (0.530627,0.193289,0)
*>* I
*>* It generates a mesh this time. What do the above error mean? Can I
*>* reliably use the mesh despite the above errors? Also the resulting
*>* mesh size is huge. Is there any intelligible way of controlling this?
*
Krishna - I'll look into the problem when I have some spare time.
Meanwhile, you can always use the Netgen 3D algorithm (beware that all
the surfaces that bound a volume have to be defined with exterior
pointing normals in this case).
Best,
Christophe
--
Christophe Geuzaine
Applied and Computational Mathematics, Caltech
geuzaine at acm.caltech.edu - http://geuz.org