# [Gmsh] Geometry definition problem.

olivier olivier at approximity.com
Wed Jun 11 23:53:25 CEST 2003

```Dear GMSH users,

I am a newbie.

I'm trying to build a mesh. Its geometry is defined by two
cylinders intersecting in the middle. When I try to build the mesh,
the error message is that the boundary is not recovered. The reason
seems to be that the geometry does not properly define the surface
of the volume.

How can I change it? Do I need to calculate the intersection
points of the two cylinders?

Thank you very much for your time and effort,

Olivier..

-------------- next part --------------
Point(1) = {-0.5,0,0,0.1};
Point(2) = {0,0,0,0.1};
Point(3) = {0.5,0,0,0.1};
Point(4) = {0.,0.5,0,0.1};
Circle(1) = {1,2,4};
Circle(2) = {4,2,3};
Point(5) = {0.,-0.5,0,0.1};
Circle(3) = {3,2,5};
Circle(4) = {5,2,1};
Line Loop(5) = {4,1,2,3};

Point(6) = {2.,0.,0.5,0.1};
Point(7) = {2.,0.,0.3,0.1};
Point(8) = {2.,0.,0.7,0.1};
Point(9) = {2.,0.2,0.5,0.1};
Point(10) = {2.,-0.2,0.5,0.1};

Circle(6) = {8,6,9};
Circle(7) = {9,6,7};
Circle(8) = {7,6,10};
Circle(9) = {10,6,8};
Plane Surface(10) = {5};
Line Loop(11) = {8,9,6,7};
Plane Surface(12) = {11};
Extrude Surface {10, {0,0,2}};
Extrude Surface {12, {-2,0,0}};
Surface Loop(57) = {55,12,43,47,51,56};
Surface Loop(58) = {29,10,21,25,34,33};
Volume(59) = {57};
Volume(60) = {58};
Physical Volume(2) = {59,60};
```