CGAL users discussion list

[Ramin H <>]

Thank you :) That solved the problem.

One more question: Does the direction of the normal vector for each
triangle that defines the domain matter? In other words, does the
order of vertices that define a triangle matter?

-Ramin

On Fri, Nov 20, 2009 at 8:59 AM, Stephane Tayeb
<>
 wrote:
> Ramin H wrote:
>>
>> Thank you for responding. It's ok if the boundary is approximated but
>> it looks like the algorithm does not finish it's job. I run the Mesh_3
>> example with no changes to size and approximation factors.
>>
>> I am attaching the screen shot of the out.mesh, visualized by medit.
>>
>> Also, here is the .off file that defines the cube:
>> ========= Begin of OFF file ========
>> OFF
>> 8 6 0
>> 1.632993   0.000000   1.154701
>> 0.000000   1.632993   1.154701
>> -1.632993   0.000000   1.154701
>> 0.000000  -1.632993   1.154701
>> 1.632993   0.000000  -1.154701
>> 0.000000   1.632993  -1.154701
>> -1.632993   0.000000  -1.154701
>> 0.000000  -1.632993  -1.154701
>>  4  0 1 2 3
>>  4  7 4 0 3
>>  4  4 5 1 0
>>  4  5 6 2 1
>>  4  3 2 6 7
>>  4  6 5 4 7
>> ========= End of OFF file ========
>>
>> Thanks,
>> -Ramin
>>
>> On Fri, Nov 20, 2009 at 3:49 AM, Stephane Tayeb
>> <>
>>  wrote:
>>>
>>> Hi,
>>>
>>> Ramin H wrote:
>>>>
>>>> Hi everyone,
>>>>
>>>> Before I use the 3D mesh generation functionality of CGAL 3.5 over a
>>>> complicated domain, I decided to use a cube as input to Mesh_3
>>>> example. The mesh created in out.mesh is missing parts of the surface
>>>> boundary of the cube.
>>>
>>> What do you mean by missing parts please ?
>>>
>>>> Is it possible to mesh cubes with the 3D mesh generation functionality
>>>> or they fall under "domains with sharp edges" category?
>>>
>>> Yes it is a domain with sharp edges if you want the have the edges in the
>>> mesh. The actual implementation is designed for smooth surfaces only.
>>>
>>> If you try to mesh a cube, you will only have an approximation of the
>>> edges
>>> (the element size near the edges depends of the surface approximation
>>> error
>>> criterion).
>>>
>>>> Any idea how one can possibly overcome this issue?
>>>>
>>>> Thank you,
>>>> -Ramin
>>>>
>
> Mesh_3 polyhedral domain is designed to handle triangulated surfaces. In
> your case, you use a quadrangular definition of the surface in the off file.
> That's why you have holes in the mesh.
>
> Please try the attached file instead of yours.
>
> Best,
> --
> Stephane Tayeb
> Software engineer - INRIA Sophia Antipolis
> Geometrica Project-Team
>
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>
> OFF
> 8 12 0
> 1.632993   0.000000   1.154701
> 0.000000   1.632993   1.154701
> -1.632993   0.000000   1.154701
> 0.000000  -1.632993   1.154701
> 1.632993   0.000000  -1.154701
> 0.000000   1.632993  -1.154701
> -1.632993   0.000000  -1.154701
> 0.000000  -1.632993  -1.154701
> 3 0 1 2
> 3 0 2 3
> 3 7 4 0
> 3 7 0 3
> 3 4 5 1
> 3 4 1 0
> 3 5 6 2
> 3 5 2 1
> 3 3 2 6
> 3 3 6 7
> 3 6 5 4
> 3 6 4 7
>
>