# [Gmsh] Gap between mesh and geometry

Bulent Hatipoglu hatipoglu.bulent at gmail.com
Fri Jan 30 16:00:01 CET 2015

```If there is a discontinuity in one of the lines the Gmsh does not count it
as a noddal point and a gap occurs between mes boundary and  geometry
boundary.  Please see following figures for automatically generated and
structured meshes  Is there a way to solve this issue?
I think I can divide the geometry into separate surfaces or lines and mesh
these separate surfaces/lines but this will be a workaround. I am looking
for a better solution if available.

Thanks,

Bulent

[image: Inline image 1]
Automatic/unstructured

[image: Inline image 2]
Structured

Codes used to generate these figures are here:

Automatic /unstructured mesh:
Point(1) = {100, 100, 0, 1};
Point(2) = {200, 100, 0, 1};
Point(3) = {200, 110, 0, 1};
Point(4) = {100, 115, 0, 1};
Point(5) = {103.5, 104, 0, 1};
Point(6) = {150, 115, 0, 1};
Point(7) = {170, 110, 0, 1};
Point(8) = {150, 100, 0, 1};
Point(9) = {170, 100, 0, 1};
Line(1) = {1,8,9, 2 };
Line(2) = {2, 3};
Line(3) = {4,6,7, 3};
Line(4) = {4, 1};
Line Loop(6) = {3, -2,-1,-4};
Plane Surface(6) = {6};

Structured:

Point(1) = {100, 100, 0, 1};
Point(2) = {200, 100, 0, 1};
Point(3) = {200, 110, 0, 1};
Point(4) = {100, 115, 0, 1};
Point(5) = {103.5, 104, 0, 1};
Point(6) = {150, 115, 0, 1};
Point(7) = {170, 110, 0, 1};
Point(8) = {150, 100, 0, 1};
Point(9) = {170, 100, 0, 1};

Line(1) = {1,8,9, 2 };
Transfinite Line {1} = 12 Using Progression 1;
Line(2) = {2, 3};
Transfinite Line {2} = 7 Using Progression 1;
Line(3) = {4,6,7, 3};
Transfinite Line {3} = 12 Using Progression 1;
Line(4) = {4, 1};
Transfinite Line {4} = 7 Using Progression 1;
Line Loop(6) = {3, -2, -1, -4};
Plane Surface(6) = {6};
Transfinite Surface {6};
Recombine Surface {6};
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