# Issue in generating Tetrahedron mesh

**URL:** <https://fenicsproject.discourse.group/t/issue-in-generating-tetrahedron-mesh/940>\
**Category:** mesh\
**Created:** [June 4, 2019, 6:32am UTC](https://fenicsproject.discourse.group/t/issue-in-generating-tetrahedron-mesh/940 "2019-06-04T06:32:30Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![agerami](https://avatars.discourse-cdn.com/v4/letter/a/e47774/32.png) [@agerami](https://fenicsproject.discourse.group/u/agerami)\
**Post date:** [June 4, 2019, 6:32am UTC](https://fenicsproject.discourse.group/t/issue-in-generating-tetrahedron-mesh/940/1 "2019-06-04T06:32:30Z")

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Hi Fenics Community,

I am trying to use Tetrahedron from mshr as follow:

> from dolfin import \*  
> from mshr import \*  
> import matplotlib.pyplot as plt  
> Tet1 = Tetrahedron(dolfin.Point(0.0, 44.0, 12.0), dolfin.Point(0.0, 64.0, 12.0), dolfin.Point(48.0, 64.0, 12.0), dolfin.point(0.0, 44.0, -2.0) )  
> mesh = generate\_mesh(Tet1, 4)  
> plot(mesh)  
> plt.show()

The error:

> AttributeError: ‘module’ object has no attribute ‘point’

I was looking for the source of this error from some of the available online resources but unfortunately, I couldn’t find any clue, so It would be great if someone could give me a hint in this case.

Thank you in advance,  
Ali

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<div class="post-metadata">

**Author:** ![marcomusy](https://yyz2.discourse-cdn.com/free1/user_avatar/fenicsproject.discourse.group/marcomusy/32/5632_2.png) [@marcomusy](https://fenicsproject.discourse.group/u/marcomusy)\
**Post date:** [June 4, 2019, 11:04am UTC](https://fenicsproject.discourse.group/t/issue-in-generating-tetrahedron-mesh/940/2 "2019-06-04T11:04:04Z")

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> [@agerami](#):
>
> from dolfin import \*  
> from mshr import \*  
> import matplotlib.pyplot as plt  
> Tet1 = Tetrahedron(dolfin.Point(0.0, 44.0, 12.0), dolfin.Point(0.0, 64.0, 12.0), dolfin.Point(48.0, 64.0, 12.0), dolfin.point(0.0, 44.0, -2.0) )  
> mesh = generate\_mesh(Tet1, 4)  
> plot(mesh)  
> plt.show()

```python
import dolfin
from mshr import *

Tet1 = Tetrahedron(
    dolfin.Point(0.0, 44.0, 12.0),
    dolfin.Point(0.0, 64.0, 12.0),
    dolfin.Point(48.0, 64.0, 12.0),
    dolfin.Point(0.0, 44.0, -2.0),
)
mesh = generate_mesh(Tet1, 4)

from vtkplotter.dolfin import plot
plot(mesh)

```

capital p in point!

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<div class="post-metadata">

**Author:** ![agerami](https://avatars.discourse-cdn.com/v4/letter/a/e47774/32.png) [@agerami](https://fenicsproject.discourse.group/u/agerami)\
**Post date:** [June 4, 2019, 6:59pm UTC](https://fenicsproject.discourse.group/t/issue-in-generating-tetrahedron-mesh/940/3 "2019-06-04T18:59:28Z")

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Thanks for your response.  
I am trying to get a 3D Cook membrane, so I should define more than four Tetrahedron as follows:

> from dolfin import \*  
> from mshr import \*  
> import math  
> import matplotlib.pyplot as plt  
> Cube = Box(dolfin.Point(0.0, 0.0, 0.0), dolfin.Point(48.0, 64.0, 10.0))  
> Tet1 = Tetrahedron(  
> dolfin.Point(0.0, 44.0, 12.0),  
> dolfin.Point(0.0, 64.0, 12.0),  
> dolfin.Point(48.0, 64.0, 12.0),  
> dolfin.Point(0.0, 44.0, -2.0),  
> )  
> Tet2 = Tetrahedron(  
> dolfin.Point(0.0, 44.0, 12.0),  
> dolfin.Point(0.0, 44.0, -2.0),  
> dolfin.Point(0.0, 64.0, -2.0),  
> dolfin.Point(24.0, 54.0, 12.0),  
> )  
> Tet3 = Tetrahedron(  
> dolfin.Point(0.0, 44.0, 12.0),  
> dolfin.Point(0.0, 64.0, -2.0),  
> dolfin.Point(24.0, 54.0, 12.0),  
> dolfin.Point(48.0, 64.0, -2.0),  
> )  
> Tet4 = Tetrahedron(  
> dolfin.Point(48.0, 64.0, -2.0),  
> dolfin.Point(48.0, 64.0, -2.0),  
> dolfin.Point(0.0, 64.0, -2.0),  
> dolfin.Point(24.0, 54.0, 12.0),  
> )  
> geometry = Cube - Tet1 - Tet2 - Tet3 - Tet4  
> mesh = generate\_mesh(geometry, 10)  
> plot(mesh)  
> vtkfile = dolfin.File(‘Figures/3Dcook.pvd’)  
> vtkfile \<\< mesh

But It seems generate\_mesh cannot get more than four input.

**Error:**

> Error !!!  
> Error !!!  
> [0]PETSC ERROR: ------------------------------------------------------------------------  
> [0]PETSC ERROR: Caught signal number 11 SEGV: Segmentation Violation, probably memory access out of range  
> [0]PETSC ERROR: Try option -start\_in\_debugger or -on\_error\_attach\_debugger  
> [0]PETSC ERROR: or see [http://www.mcs.anl.gov/petsc/documentation/faq.html#valgrind](http://www.mcs.anl.gov/petsc/documentation/faq.html#valgrind)  
> [0]PETSC ERROR: or try [http://valgrind.org](http://valgrind.org) on GNU/linux and Apple Mac OS X to find memory corruption errors  
> [0]PETSC ERROR: configure using --with-debugging=yes, recompile, link, and run  
> [0]PETSC ERROR: to get more information on the crash.  
> application called MPI\_Abort(MPI\_COMM\_WORLD, 59) - process 0  
> [unset]: write\_line error; fd=-1 buf=:cmd=abort exitcode=59  
> :  
> system msg for write\_line failure : Bad file descriptor

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<div class="post-metadata">

**Author:** ![marcomusy](https://yyz2.discourse-cdn.com/free1/user_avatar/fenicsproject.discourse.group/marcomusy/32/5632_2.png) [@marcomusy](https://fenicsproject.discourse.group/u/marcomusy)\
**Post date:** [June 5, 2019, 10:43am UTC](https://fenicsproject.discourse.group/t/issue-in-generating-tetrahedron-mesh/940/4 "2019-06-05T10:43:45Z")

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> [@agerami](#):
>
> Tet4 = Tetrahedron(  
> dolfin.Point(48.0, 64.0, -2.0),  
> dolfin.Point(48.0, 64.0, -2.0),

this is one possible issue…