CGAL surface mesh simplification - how to get compact triangular faces?

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CGAL surface mesh simplification - how to get compact triangular faces?

Audette, Michel A.
Dear CGAL experts, 

my student Shrabani Ghosh has been using the Triangulated Surface Mesh Simplification algorithm, in attempting to decimate a surface model of the human cranium. This model makes explicit the cranial openings, or foramina, and we are adopting a decimation strategy where the foramina faces are held as constant. My question to the community is: how can we ensure that the surface mesh produces compact triangular faces? If I look at what our results look like, and compare that to the three hand models on the website, the hand models have exquisite compact triangles everywhere, while our results have a number of elongated faces. Is this a parameter in the simplification that we can set, in order to make the decimation define new faces with low aspect ratios? 

Thanks for your kind support. Best wishes,

Michel

Michel Audette, Ph.D.
Associate Professor,
Department of Computational Modeling and Simulation Engineering,
Old Dominion University,
Norfolk, VA.
 
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Re: CGAL surface mesh simplification - how to get compact triangular faces?

Sebastien Loriot (GeometryFactory)
Could you explain what you mean with compact triangle?

Maybe some screeshots would help.

Sebastien.

On 10/25/19 5:02 PM, Audette, Michel A. wrote:

> Dear CGAL experts,
>
> my student Shrabani Ghosh has been using the Triangulated Surface Mesh
> Simplification algorithm, in attempting to decimate a surface model of
> the human cranium. This model makes explicit the cranial openings, or
> foramina, and we are adopting a decimation strategy where the foramina
> faces are held as constant. My question to the community is: how can we
> ensure that the surface mesh produces compact triangular faces? If I
> look at what our results look like, and compare that to the three hand
> models on the website, the hand models have exquisite compact triangles
> everywhere, while our results have a number of elongated faces. Is this
> a parameter in the simplification that we can set, in order to make the
> decimation define new faces with low aspect ratios?
>
> Thanks for your kind support. Best wishes,
>
> Michel
>
> Michel Audette, Ph.D.
> Associate Professor,
> Department of Computational Modeling and Simulation Engineering,
> Old Dominion University,
> Norfolk, VA.

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Re: CGAL surface mesh simplification - how to get compact triangular faces?

Shrabani Ghosh
Thank You Sebastien for your response.
I am attaching here a snapshot.

<http://cgal-discuss.949826.n4.nabble.com/file/t376134/Untitled.png>


Regards
Shrabani Ghosh



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Re: CGAL surface mesh simplification - how to get compact triangular faces?

Sebastien Loriot (GeometryFactory)
Could you show what is the input of the simplification algorithm and
what is the output?

What stop criteria did you use? How did you constrain edges?

Sebastien.

On 10/28/19 8:01 PM, Shrabani Ghosh wrote:

> Thank You Sebastien for your response.
> I am attaching here a snapshot.
>
> <http://cgal-discuss.949826.n4.nabble.com/file/t376134/Untitled.png>
>
>
> Regards
> Shrabani Ghosh
>
>
>
> --
> Sent from: http://cgal-discuss.949826.n4.nabble.com/
>

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Re: CGAL surface mesh simplification - how to get compact triangular faces?

Shrabani Ghosh
I could not attach it in the email. I am sharing it in the drive.
The stop criteria is:
  SMS::Count_ratio_stop_predicate<Surface_mesh> stop(0.9);
I have a list of edges in the text file which I kept as constraint in the process.
I have attached .cpp file also.



Regards
Shrabani Ghosh



On Tue, Oct 29, 2019 at 2:27 AM Sebastien Loriot (GeometryFactory) <[hidden email]> wrote:
Could you show what is the input of the simplification algorithm and
what is the output?

What stop criteria did you use? How did you constrain edges?

Sebastien.

On 10/28/19 8:01 PM, Shrabani Ghosh wrote:
> Thank You Sebastien for your response.
> I am attaching here a snapshot.
>
> <http://cgal-discuss.949826.n4.nabble.com/file/t376134/Untitled.png>
>
>
> Regards
> Shrabani Ghosh
>
>
>
> --
> Sent from: http://cgal-discuss.949826.n4.nabble.com/
>

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