# What is wrong with my mesh?

**URL:** <https://fenicsproject.discourse.group/t/what-is-wrong-with-my-mesh/7504>\
**Category:** mesh\
**Created:** [January 19, 2022, 6:21pm UTC](https://fenicsproject.discourse.group/t/what-is-wrong-with-my-mesh/7504 "2022-01-19T18:21:33Z")\
**Posts on this page:** 13\
**Page:** 1

<div class="post-metadata">

**Author:** ![SvenH](https://avatars.discourse-cdn.com/v4/letter/s/eb8c5e/32.png) [@SvenH](https://fenicsproject.discourse.group/u/SvenH)\
**Post date:** [January 19, 2022, 6:21pm UTC](https://fenicsproject.discourse.group/t/what-is-wrong-with-my-mesh/7504/1 "2022-01-19T18:21:33Z")

</div>

Hi,  
I have created a mesh with gmsh and I am having trouble importing it into my script.  
Dolfin has trouble reading the facets xdmf file and shows the following error message:

```auto
*** Error: Unable to find entity in map.
*** Reason: Error reading MeshValueCollection.
*** Where: This error was encountered inside HDF5File.cpp. 

```

this is my .geo file:

```auto
// Gmsh project created on Tue Jan 18 10:52:11 2022
SetFactory("OpenCASCADE");
//+
Point(1) = {0, 0, 0, 1.0};
//+
Point(3) = {0.007421, 0.001296, 0, 1.0};
//+
Point(5) = {0.007421, 0.002798, 0, 1.0};
//+
Point(6) = {0.007421, 0.003812, 0, 1.0};
//+
Point(7) = {0.007421, 0.002748, 0, 1.0};
//+
Point(8) = {0.006405, 0.001273, 0, 1.0};
//+
Point(9) = {0.006405, 0.002727, 0, 1.0};
//+
Point(10) = {0.006405, 0.002783, 0, 1.0};
//+
Point(11) = {0.006405, 0.003791, 0, 1.0};
//+
Point(12) = {0.005553, 0.001266, 0, 1.0};
//+
Point(13) = {0.005553, 0.002718, 0, 1.0};
//+
Point(14) = {0.005553, 0.002769, 0, 1.0};
//+
Point(15) = {0.005553, 0.003788, 0, 1.0};
//+
Point(16) = {0.004349, 0.001228, 0, 1.0};
//+
Point(17) = {0.004349, 0.002597, 0, 1.0};
//+
Point(18) = {0.004349, 0.002660, 0, 1.0};
//+
Point(19) = {0.004349, 0.003704, 0, 1.0};
//+
Point(20) = {0.004120, 0.000980, 0, 1.0};
//+
Point(21) = {0.004120, 0.002534, 0, 1.0};
//+
Point(22) = {0.004120, 0.002596, 0, 1.0};
//+
Point(23) = {0.004120, 0.003669, 0, 1.0};
//+
Point(24) = {0.003964, 0.00-0.000688, 0, 1.0};
//+
Point(25) = {0.003964, 0.002482, 0, 1.0};
//+
Point(26) = {0.003964, 0.002542, 0, 1.0};
//+
Point(27) = {0.003964, 0.003631, 0, 1.0};
//+
Point(28) = {0.003535, -0.000730, 0, 1.0};
//+
Point(29) = {0.003535, 0.002272, 0, 1.0};
//+
Point(30) = {0.003535, 0.002336, 0, 1.0};
//+
Point(31) = {0.003535, 0.003501, 0, 1.0};
//+
Point(32) = {0.003227, -0.000693, 0, 1.0};
//+
Point(33) = {0.003227, 0.002033, 0, 1.0};
//+
Point(34) = {0.003227, 0.002101, 0, 1.0};
//+
Point(35) = {0.003227, 0.003370, 0, 1.0};
//+
Point(36) = {0.002993, 0.001490, 0, 1.0};
//+
Point(37) = {0.002993, 0.003231, 0, 1.0};
//+
Point(38) = {0.002993, -0.000661, 0, 1.0};
//+
Point(39) = {0.002790, 0.003081, 0, 1.0};
//+
Point(40) = {0.002670, -0.000627, 0, 1.0};
//+
Point(41) = {0.002670, 0.000256, 0, 1.0};
//+
Point(42) = {0.002395, 0, 0, 1.0};
//+
Point(43) = {0, -0.000660, 0, 1.0};
//+
Line(1) = {1, 42};
//+
Point(44) = {0, 0, 0, 1.0};
//+
Point(45) = {0, 0, -0, 1.0};
//+
Point(46) = {0, 0, -0, 1.0};
//+
Point(47) = {0, 0, -0, 1.0};
//+
Point(48) = {0, 0, -0, 1.0};
//+
Point(49) = {0, 0, -0, 1.0};
//+
Point(50) = {0, 0, -0, 1.0};
//+
Point(51) = {0, 0, -0, 1.0};
//+
Point(52) = {0, 0, -0, 1.0};
//+
Point(53) = {0, 0, -0, 1.0};
//+
Point(54) = {0, 0, -0, 1.0};
//+
Point(55) = {0, 0, -0, 1.0};
//+
Point(56) = {0, 0, -0, 1.0};
//+
Point(57) = {0, 0, -0, 1.0};
//+
Point(58) = {0, 0, -0, 1.0};
//+
Point(59) = {0, 0, -0, 1.0};
//+
Point(60) = {0, 0, -0, 1.0};
//+
Line(2) = {41, 39};
//+
Spline(3) = {39, 37, 35, 31};
//+
Spline(4) = {31, 27, 23, 19};
//+
Spline(5) = {19, 15, 11, 6};
//+
Line(6) = {6, 5};
//+
Spline(7) = {5, 10, 14};
//+
Spline(8) = {14, 18, 22};
//+
Spline(9) = {22, 26, 30, 34, 36};
//+
Spline(10) = {36, 33, 29, 25};
//+
Spline(11) = {25, 21, 17, 13};
//+
Spline(12) = {13, 9, 7};
//+
Line(13) = {3, 7};
//+
Spline(14) = {3, 8, 12};
//+
Line(15) = {12, 16};
//+
Line(16) = {16, 20};
//+
Line(17) = {20, 24};
//+
Line(18) = {24, 28};
//+
Line(19) = {28, 32};
//+
Line(20) = {32, 38};
//+
Line(21) = {38, 40};
//+
Line(22) = {40, 43};
//+
Point(61) = {0, 0, -0, 1.0};
//+
Point(62) = {0, 0, -0, 1.0};
//+
Point(63) = {0, 0, -0, 1.0};
//+
Point(64) = {0, 0, -0, 1.0};
//+
Point(65) = {0, 0, -0, 1.0};
//+
Point(66) = {0.002598, 0.000107, 0, 1.0};
//+
Spline(23) = {41, 66, 42};
//+
Point(67) = {0, -0.000284, 0, 1.0};
//+
Point(68) = {0.000698, -0.000284, 0, 1.0};
//+
Point(69) = {0.001298, -0.000322, 0, 1.0};
//+
Point(70) = {0.001522, -0.000314, 0, 1.0};
//+
Point(71) = {0.003118, -0.000029, 0, 1.0};
//+
Point(72) = {0.003166, 0.000059, 0, 1.0};
//+
Point(73) = {0.003118, 0.000710, 0, 1.0};
//+
Line(25) = {67, 68};
//+
Spline(26) = {68, 69, 70};
//+
Spline(30) = {36, 73, 72, 71};
//+
Line(31) = {71, 70};
//+
Symmetry {1, 0, 0, 0} {
  Duplicata { Curve{1}; Curve{23}; Curve{2}; Curve{3}; Curve{4}; Curve{5}; Curve{6}; Curve{7}; Curve{8}; Curve{9}; Curve{30}; Curve{31}; Curve{26}; Curve{25}; Curve{22}; Curve{21}; Curve{20}; Curve{19}; Curve{18}; Curve{17}; Curve{16}; Curve{15}; Curve{14}; Curve{13}; Curve{12}; Curve{11}; Curve{10}; }
}
//+
Symmetry {1, 0, 0, 0} {
  Duplicata { Point{66}; Point{37}; Point{35}; Point{27}; Point{23}; Point{11}; Point{33}; Point{29}; Point{25}; Point{21}; Point{9}; Point{8}; }
}
//+
Symmetry {1, 0, 0, 0} {
  Duplicata { Point{34}; Point{30}; Point{26}; }
}
//+
Symmetry {1, 0, 0, 0} {
  Duplicata { Point{14}; }
}
//+
Symmetry {1, 0, 0, 0} {
  Duplicata { Point{14}; }
}
//+
Symmetry {1, 0, 0, 0} {
  Duplicata { Point{10}; }
}
//+
Symmetry {1, 0, 0, 0} {
  Duplicata { Point{15}; }
}
//+
Symmetry {1, 0, 0, 0} {
  Duplicata { Point{70}; }
}
//+
Symmetry {1, 0, 0, 0} {
  Duplicata { Point{69}; }
}
//+
Symmetry {1, 0, 0, 0} {
  Duplicata { Point{71}; }
}
//+
Symmetry {1, 0, 0, 0} {
  Duplicata { Point{72}; }
}
//+
Symmetry {1, 0, 0, 0} {
  Duplicata { Point{73}; }
}
//+
Symmetry {1, 0, 0, 0} {
  Duplicata { Point{26}; }
}
//+
Symmetry {1, 0, 0, 0} {
  Duplicata { Point{22}; }
}
//+
Symmetry {1, 0, 0, 0} {
  Duplicata { Point{18}; }
}
//+
Symmetry {1, 0, 0, 0} {
  Duplicata { Point{17}; }
}
Curve Loop(1) = {1,23,2,3,4,5,6,7,8,9,30,31,26,25,45,44,43,42,41,40,39,38,37,36,35,34,33,32};
Plane Surface (1) = {1};
Curve Loop(2) = {25,26,31,30,10,11,12,13,14,15,16,17,18,19,20,21,22,46,47,48,49,50,51,52,53,54,55,56,57,58,42,43,44,45};
Plane Surface(2) = {2};
//+
Physical Curve(1) = {35, 37, 36, 34, 32, 33, 1, 23, 2, 3, 5, 4};
//+
Physical Curve(2) = {38};
//+
Physical Curve(3) = {6};
//+
Physical Curve(4) = {8, 10, 9, 7, 11, 12};
//+
Physical Curve(5) = {13};
//+
Physical Curve(6) = {14, 15, 16, 17, 18, 19, 20, 21, 22, 46, 47, 48, 49, 50, 51, 52, 53, 54};
//+
Physical Curve(7) = {55};
//+
Physical Curve(8) = {56, 57, 58, 41, 40, 39};
//+
Physical Curve(11) = {42, 43, 44, 45, 25, 26, 31, 30};
//+
Physical Surface(9) = {1};
//+
Physical Surface(10) = {2};

```

I am using the following code to import the mesh:

```auto
mesh = Mesh()

with XDMFFile("mesh.xdmf") as infile:
    infile.read(mesh)

mvc = MeshValueCollection("size_t", mesh, 1)
with XDMFFile("mf.xdmf") as infile:
    infile.read(mvc, "Boundary")

```

I’m thankful for any suggestions for what might be wrong with my mesh

**Edit 1**  
Code for mesh conversion:

```auto
import meshio
import numpy as np

# import mesh file from gmesh
msh = meshio.read('mesh.msh')

# make
line_cells = []
for cell in msh.cells:
    if cell.type == "triangle":
        triangle_cells = cell.data
    elif cell.type == "line":
        if len(line_cells) == 0:
            line_cells = cell.data
        else:
            line_cells = np.vstack([line_cells, cell.data])

line_data = []
for key in msh.cell_data_dict["gmsh:physical"].keys():
    if key == "line":
        if len(line_data) == 0:
            line_data = msh.cell_data_dict["gmsh:physical"][key]
        else:
            line_data = np.vstack([line_data, msh.cell_data_dict["gmsh:physical"][key]])
    elif key == "triangle":
        triangle_data = msh.cell_data_dict["gmsh:physical"][key]

triangle_mesh = meshio.Mesh(points=msh.points[:, :2], cells={"triangle": triangle_cells})
line_mesh =meshio.Mesh(points=msh.points[:, :2],
                           cells=[("line", line_cells)],
                           cell_data={"Boundary":[line_data]})
meshio.write("mesh.xdmf", triangle_mesh)

meshio.xdmf.write("mf.xdmf", line_mesh)

```

---

<div class="post-metadata">

**Author:** ![dokken](https://yyz2.discourse-cdn.com/free1/user_avatar/fenicsproject.discourse.group/dokken/32/1560_2.png) [@dokken](https://fenicsproject.discourse.group/u/dokken)\
**Post date:** [January 19, 2022, 7:43pm UTC](https://fenicsproject.discourse.group/t/what-is-wrong-with-my-mesh/7504/2 "2022-01-19T19:43:42Z")

</div>

You need to add the script/code you used to convert the geo file to xdmf as well for anyone to properly assist you.

---

<div class="post-metadata">

**Author:** ![SvenH](https://avatars.discourse-cdn.com/v4/letter/s/eb8c5e/32.png) [@SvenH](https://fenicsproject.discourse.group/u/SvenH)\
**Post date:** [January 20, 2022, 7:33am UTC](https://fenicsproject.discourse.group/t/what-is-wrong-with-my-mesh/7504/3 "2022-01-20T07:33:56Z")

</div>

Thanks, I added the code at the bottom of the original post. I create the mesh and export the .msh file with the gmsh GUI.

---

<div class="post-metadata">

**Author:** ![dokken](https://yyz2.discourse-cdn.com/free1/user_avatar/fenicsproject.discourse.group/dokken/32/1560_2.png) [@dokken](https://fenicsproject.discourse.group/u/dokken)\
**Post date:** [January 20, 2022, 8:07am UTC](https://fenicsproject.discourse.group/t/what-is-wrong-with-my-mesh/7504/4 "2022-01-20T08:07:23Z")

</div>

The issue with your mesh is that several of the boundaries you have marked is not part of a volume mesh, see attached images:

 ![mesh_boundary](https://global.discourse-cdn.com/free1/uploads/fenicsproject1/original/2X/3/34f3c8f0dba0b3c5cb55da602bbf08a00999a780.png)  
 ![mesh_boundary2](https://global.discourse-cdn.com/free1/uploads/fenicsproject1/original/2X/9/975233220fd16d72179ba189cea506133416ddba.png)

Note that you can easily inspect your mesh and boundary xdmf file using Paraview.

---

<div class="post-metadata">

**Author:** ![SvenH](https://avatars.discourse-cdn.com/v4/letter/s/eb8c5e/32.png) [@SvenH](https://fenicsproject.discourse.group/u/SvenH)\
**Post date:** [January 20, 2022, 8:36am UTC](https://fenicsproject.discourse.group/t/what-is-wrong-with-my-mesh/7504/5 "2022-01-20T08:36:14Z")

</div>

The small gaps without mesh on the left and right side are intended. I didn’t think this would be a problem. Thank you, I will look into this.

---

<div class="post-metadata">

**Author:** ![dokken](https://yyz2.discourse-cdn.com/free1/user_avatar/fenicsproject.discourse.group/dokken/32/1560_2.png) [@dokken](https://fenicsproject.discourse.group/u/dokken)\
**Post date:** [January 20, 2022, 9:19am UTC](https://fenicsproject.discourse.group/t/what-is-wrong-with-my-mesh/7504/6 "2022-01-20T09:19:35Z")

</div>

The point is that there is no mesh (cells) attached to those facets, which will cause the reading of boundary markers to fail, as it cannot find any cell with those facets.

---

<div class="post-metadata">

**Author:** ![SvenH](https://avatars.discourse-cdn.com/v4/letter/s/eb8c5e/32.png) [@SvenH](https://fenicsproject.discourse.group/u/SvenH)\
**Post date:** [January 20, 2022, 9:34am UTC](https://fenicsproject.discourse.group/t/what-is-wrong-with-my-mesh/7504/7 "2022-01-20T09:34:05Z")

</div>

Sorry, I’m not quite sure whether I understand correctly. This is what the mesh looks like on my end in paraview:

 ![Screenshot from 2022-01-20 10-26-59](https://global.discourse-cdn.com/free1/uploads/fenicsproject1/original/2X/a/a06e88b93e7c8c929b67dcd316f997908f6c9f44.jpeg)  
which at least looks like what I want it to.

---

<div class="post-metadata">

**Author:** ![dokken](https://yyz2.discourse-cdn.com/free1/user_avatar/fenicsproject.discourse.group/dokken/32/1560_2.png) [@dokken](https://fenicsproject.discourse.group/u/dokken)\
**Post date:** [January 20, 2022, 10:19am UTC](https://fenicsproject.discourse.group/t/what-is-wrong-with-my-mesh/7504/8 "2022-01-20T10:19:22Z")

</div>

Using a slightly different conversion syntax, I can reproduce your domain with XDMF.

```python
import meshio
import numpy as np

def create_mesh(mesh: meshio.Mesh, cell_type: str, data_name: str = "name_to_read",
                prune_z: bool = False):
    cells = mesh.get_cells_type(cell_type)
    cell_data = mesh.get_cell_data("gmsh:physical", cell_type)
    points = mesh.points[:, :2] if prune_z else mesh.points
    out_mesh = meshio.Mesh(points=points, cells={cell_type: cells}, cell_data={
                           data_name: [cell_data]})
    return out_mesh

# import and convert msh file to xdmf
msh = meshio.read('mesh.msh')
line_mesh = create_mesh(msh, "line", data_name="Boundary", prune_z=True)
meshio.write("mf.xdmf", line_mesh)
triangle_mesh = create_mesh(msh, "triangle", prune_z=True)
meshio.write("mesh.xdmf", triangle_mesh)

```

The issue is that you have tagged facets that are not actually in the mesh.  
This can be shown by calling:

```python
points_in_facets = np.unique(np.sort(msh.get_cells_type("line").reshape(-1)))
points_in_cells = np.sort(
    np.unique(msh.get_cells_type("triangle").reshape(-1)))
vertices_in_facets_not_cells = np.isin(
    points_in_facets, points_in_cells, invert=True)
print(msh.points[np.flatnonzero(vertices_in_facets_not_cells)])

```

All the vertices printed here are vertices that are found in your facet mesh, but not in your actual mesh.

The problem is probably how you duplicate points of your mesh. However, as I do not really use the GMSH geo format (I rather use the gmsh python API), I don’t know a workaround for your problem.

---

<div class="post-metadata">

**Author:** ![SvenH](https://avatars.discourse-cdn.com/v4/letter/s/eb8c5e/32.png) [@SvenH](https://fenicsproject.discourse.group/u/SvenH)\
**Post date:** [January 20, 2022, 11:19am UTC](https://fenicsproject.discourse.group/t/what-is-wrong-with-my-mesh/7504/9 "2022-01-20T11:19:36Z")

</div>

Thank you for your time, Dokken. The problem arose from the transform option called “symmetry”. Apparently, you are not supposed to use curves as entities, just points and then connect them manually. It works perfectly fine now.

---

<div class="post-metadata">

**Author:** ![Rafael\_Ferro](https://yyz2.discourse-cdn.com/free1/user_avatar/fenicsproject.discourse.group/rafael_ferro/32/1157_2.png) [@Rafael\_Ferro](https://fenicsproject.discourse.group/u/Rafael_Ferro)\
**Post date:** [February 17, 2023, 8:28pm UTC](https://fenicsproject.discourse.group/t/what-is-wrong-with-my-mesh/7504/10 "2023-02-17T20:28:27Z")

</div>

What about a 3D mesh? I made the following code but the faces do not appear, the file is blank.

````auto
import meshio
import numpy as np

def create_mesh(mesh: meshio.Mesh, cell_type: str, data_name: str = "name_to_read",
                prune_z: bool = False):
    cells = mesh.get_cells_type(cell_type)
    cell_data = mesh.get_cell_data("gmsh:physical", cell_type)
    points = mesh.points[:, :2] if prune_z else mesh.points
    out_mesh = meshio.Mesh(points=points, cells={cell_type: cells}, cell_data={
                           data_name: [cell_data]})
    return out_mesh

# import and convert msh file to xdmf
msh = meshio.read('test.msh')
#line_mesh = create_mesh(msh, "line", data_name="Boundary", prune_z=True)
#meshio.write("test_mf.xdmf", line_mesh)

facet_mesh = create_mesh(msh, "triangle", prune_z=True)
meshio.write("test_facet.xdmf", facet_mesh)

triangle_mesh = create_mesh(msh, "tetra", prune_z=True)
meshio.write("test_mesh.xdmf", triangle_mesh)
```
````

---

<div class="post-metadata">

**Author:** ![dokken](https://yyz2.discourse-cdn.com/free1/user_avatar/fenicsproject.discourse.group/dokken/32/1560_2.png) [@dokken](https://fenicsproject.discourse.group/u/dokken)\
**Post date:** [February 17, 2023, 11:02pm UTC](https://fenicsproject.discourse.group/t/what-is-wrong-with-my-mesh/7504/11 "2023-02-17T23:02:23Z")

</div>

> [@Rafael\_Ferro](#):
>
> ```auto
> facet_mesh = create_mesh(msh, "triangle", prune_z=True)
> meshio.write("test_facet.xdmf", facet_mesh)
> 
> triangle_mesh = create_mesh(msh, "tetra", prune_z=True)
> meshio.write("test_mesh.xdmf", triangle_mesh)
> 
> ```

Why are you pruning the z coordinate if your mesh is 3D?

As you haven’t supplied the msh file or the geo file, there isn’t much more people can do to help you.

---

<div class="post-metadata">

**Author:** ![Rafael\_Ferro](https://yyz2.discourse-cdn.com/free1/user_avatar/fenicsproject.discourse.group/rafael_ferro/32/1157_2.png) [@Rafael\_Ferro](https://fenicsproject.discourse.group/u/Rafael_Ferro)\
**Post date:** [February 18, 2023, 12:28am UTC](https://fenicsproject.discourse.group/t/what-is-wrong-with-my-mesh/7504/12 "2023-02-18T00:28:10Z")

</div>

I think I got it now, I changed 2 for 3 on the line:

```auto
points = mesh.points[:, :3] if prune_z else mesh.points

```

is this correct?

gmsh’s code is simple:

```auto
// Gmsh project created on Fri Feb 17 16:59:21 2023
SetFactory("OpenCASCADE");
//+
Box(1) = {0, 0, 0, 1, 1, 0.02};
//+
Physical Volume(13) = {1};
//+
Physical Surface(14) = {3, 4};

```

---

<div class="post-metadata">

**Author:** ![dokken](https://yyz2.discourse-cdn.com/free1/user_avatar/fenicsproject.discourse.group/dokken/32/1560_2.png) [@dokken](https://fenicsproject.discourse.group/u/dokken)\
**Post date:** [February 18, 2023, 9:04am UTC](https://fenicsproject.discourse.group/t/what-is-wrong-with-my-mesh/7504/13 "2023-02-18T09:04:45Z")

</div>

I cannot reproduce any errors with:

```python
import meshio
import numpy as np

def create_mesh(mesh: meshio.Mesh, cell_type: str, data_name: str = "name_to_read",
                prune_z: bool = False):
    cells = mesh.get_cells_type(cell_type)
    cell_data = mesh.get_cell_data("gmsh:physical", cell_type)
    points = mesh.points[:, :2] if prune_z else mesh.points
    out_mesh = meshio.Mesh(points=points, cells={cell_type: cells}, cell_data={
                           data_name: [cell_data]})
    return out_mesh

# import and convert msh file to xdmf
msh = meshio.read('mesh.msh')

print(msh)
facet_mesh = create_mesh(msh, "triangle")
meshio.write("test_facet.xdmf", facet_mesh)

triangle_mesh = create_mesh(msh, "tetra")
meshio.write("test_mesh.xdmf", triangle_mesh)

```

which prints

```bash

<meshio mesh object>
  Number of points: 199
  Number of cells:
    triangle: 16
    triangle: 16
    tetra: 512
  Cell sets: gmsh:bounding_entities
  Point data: gmsh:dim_tags
  Cell data: gmsh:physical, gmsh:geometrical

```

Please look at all the other posts regarding gmsh/meshio

> [@Transitioning from mesh.xml to mesh.xdmf, from dolfin-convert to meshio](https://fenicsproject.discourse.group/t/transitioning-from-mesh-xml-to-mesh-xdmf-from-dolfin-convert-to-meshio/412/174):
>
> As far as I can tell you would like to have a 3D mesh (tetrahedrons). Then you also need to mark the volumes: // Gmsh project created on Tue May 18 16:34:55 2021 SetFactory("OpenCASCADE"); //+ Circle(1) = {0, 00, 00, 0.6, 0, 2\*Pi}; //+ Circle(2) = {0, 00, 00, 0.4, 0, 2\*Pi}; //+ Curve Loop(1) = {1}; //+ Curve Loop(2) = {2}; //+ Plane Surface(1) = {1, 2}; //+ Extrude {0, 0, 10} { Curve{2}; Curve{1}; Layers {1}; Recombine; } //+ Curve Loop(5) = {6}; //+ Curve Loop(6) = {4}; //+ Plane Surface(4) …

> [@Need help converting GMSH to FEniCS](https://fenicsproject.discourse.group/t/need-help-converting-gmsh-to-fenics/5192/54):
>
> Please note that you have some errors in your geo-file, i.e. Correcting these, and adding Physical Surface("surf", 1) = {2}; at the end, the following file (mesh.geo) // Gmsh project created on Thu Nov 18 16:23:27 2021 SetFactory("OpenCASCADE"); Rectangle(1) = {0, 0, 0, 18, 6, 0}; Point(5) = {3, 2.8, 0, 0.05}; Point(6) = {3, 3.2, 0, 0.05}; Point(7) = {3.3464, 3.4, 0, 0.05}; Point(8) = {3.3464, 2.6, 0, 0.05}; Point(9) = {3.6928, 2.8, 0, 0.05}; Point(10) = {3.6928, 3.2, 0, 0.05}; Point(11) = …

as they contain a lot of tips and tricks.