Removing non-manifold edges and vertices

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Removing non-manifold edges and vertices

weiherer.maximilian

Hi all,

 

does CGAL provide a convenient method for removing non-manifold edges and vertices? I don’t find any.

 

Any help would be appreciated.

 

Best regards

Maximilian

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Re: Removing non-manifold edges and vertices

Sebastien Loriot (GeometryFactory)
what do you mean by removing?
We can resolve them by duplicating the vertices which will result in a
geometric self-intersection.
If you want to geometrically resolve them there are some techniques that
we applied in some algorithm that might be useful to expose in the API,
but this one is not yet available.

Sebastien.

On 07/26/2018 09:59 AM, Maximilian Weiherer wrote:

> Hi all,
>
> does CGAL provide a convenient method for removing non-manifold edges
> and vertices? I don’t find any.
>
> Any help would be appreciated.
>
> Best regards
>
> Maximilian
>

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AW: [cgal-discuss] Removing non-manifold edges and vertices

weiherer.maximilian
Ok so let me explain what I'm trying to do: I want to apply some boolean
operations on surface meshes with a highly complex geometry. As far as I
know, CGAL therefore provides two different packages: 3D Polyhedral Surface
and 3D Boolean Operations on Nef Polyhedra.
The latter allows me to deal with non-manifold meshes which is probably the
best choice as boolean operations (especially on complex geometries) often
results in non-manifoldness. Unfortunately, Nef Polyhedra did not work for
the meshes I use as they consist of more than 1.000.000 vertices (my program
always crashes when I try to convert a polyhedral input mesh to a Nef
polyhedral). By the way, are there any suggestions how to deal with this (I
guess the size of the input meshes is too big)?
The alternative is to use the 3D Polyhedral package. Using this package,
boolean operations can result in non-manifold meshes. So I need to
geometrically resolve non-manifoldness.

Thanks for any suggestions.

Best regards
Maximilian

-----Ursprüngliche Nachricht-----
Von: [hidden email] <[hidden email]> Im
Auftrag von Sebastien Loriot (GeometryFactory)
Gesendet: Donnerstag, 26. Juli 2018 10:12
An: [hidden email]
Betreff: Re: [cgal-discuss] Removing non-manifold edges and vertices

what do you mean by removing?
We can resolve them by duplicating the vertices which will result in a
geometric self-intersection.
If you want to geometrically resolve them there are some techniques that we
applied in some algorithm that might be useful to expose in the API, but
this one is not yet available.

Sebastien.

On 07/26/2018 09:59 AM, Maximilian Weiherer wrote:

> Hi all,
>
> does CGAL provide a convenient method for removing non-manifold edges
> and vertices? I don’t find any.
>
> Any help would be appreciated.
>
> Best regards
>
> Maximilian
>

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Re: Removing non-manifold edges and vertices

Sebastien Loriot (GeometryFactory)
If your mesh is large, Nef will consume too much memory and you'll not
be able to perform the operation requested.

Using the corefinement based operations in the Polygon Mesh Processing
package will indeed not produce meshes with non-manifold edges.
It is something that I'm thinking about adding but I'll need some time
and financing.

If you can share a typical operation that you'd like to perform (you can
share it in private message), I can have a quick look to see if there is
workaround that would apply to your setting.

Sebastien.

On 08/01/2018 11:53 PM, [hidden email] wrote:

> Ok so let me explain what I'm trying to do: I want to apply some boolean
> operations on surface meshes with a highly complex geometry. As far as I
> know, CGAL therefore provides two different packages: 3D Polyhedral Surface
> and 3D Boolean Operations on Nef Polyhedra.
> The latter allows me to deal with non-manifold meshes which is probably the
> best choice as boolean operations (especially on complex geometries) often
> results in non-manifoldness. Unfortunately, Nef Polyhedra did not work for
> the meshes I use as they consist of more than 1.000.000 vertices (my program
> always crashes when I try to convert a polyhedral input mesh to a Nef
> polyhedral). By the way, are there any suggestions how to deal with this (I
> guess the size of the input meshes is too big)?
> The alternative is to use the 3D Polyhedral package. Using this package,
> boolean operations can result in non-manifold meshes. So I need to
> geometrically resolve non-manifoldness.
>
> Thanks for any suggestions.
>
> Best regards
> Maximilian
>
> -----Ursprüngliche Nachricht-----
> Von: [hidden email] <[hidden email]> Im
> Auftrag von Sebastien Loriot (GeometryFactory)
> Gesendet: Donnerstag, 26. Juli 2018 10:12
> An: [hidden email]
> Betreff: Re: [cgal-discuss] Removing non-manifold edges and vertices
>
> what do you mean by removing?
> We can resolve them by duplicating the vertices which will result in a
> geometric self-intersection.
> If you want to geometrically resolve them there are some techniques that we
> applied in some algorithm that might be useful to expose in the API, but
> this one is not yet available.
>
> Sebastien.
>
> On 07/26/2018 09:59 AM, Maximilian Weiherer wrote:
>> Hi all,
>>
>> does CGAL provide a convenient method for removing non-manifold edges
>> and vertices? I don’t find any.
>>
>> Any help would be appreciated.
>>
>> Best regards
>>
>> Maximilian
>>
>
> --
> You are currently subscribed to cgal-discuss.
> To unsubscribe or access the archives, go to
> https://sympa.inria.fr/sympa/info/cgal-discuss
>
>
>
>
> ---
> Diese E-Mail wurde von Avast Antivirus-Software auf Viren geprüft.
> https://www.avast.com/antivirus
>
>

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