CGAL users discussion list

[omar rodriguez <>]

Thank you very much Ben !

Omar

+



On Wed, Apr 8, 2009 at 1:23 AM, Benjamin schwarz 
<>
 wrote:
> Hello Omar and Naresh,
>
>  I wrote a few C++ lines some times ago to convert the border of an
> Alpha_shape_3 to an HDS. I cleaned my code and tried to make it more
> generic, you can download it on this webpage :
> http://alnitak.u-strasbg.fr/~schwarz/benjamin-schwarz-igbmc-Code-CGAL-AlphaPolyhedron.html#benjamin-schwarz-CGAL-Polyhedronification-Downloads
>
>  The HDS allowed me to cheat and build a "combinatorially manifold"
> object representing the border of the alpha shape for any alpha value
> (even in Alpha_shape_3::GENERAL mode), which seems to be impossible
> with the Polyhedron_3 class though it is built on a HDS.
>
>  The Polyhedron_3 class seems to redefine its iner items (such as
> Halfedges) and disallow some of their functionalities (for instance
> Halfedge::set_next() is made private). The only way to modify a
> Polyhedron inner HDS is thus to use a Polyhedron_builder_3, which
> seems to prohibit the existence of "degenerate" cases such as two
> facets with the same three corner vertices, edges sharing the same
> pair of vertices, or connections of volume (or voids) through one
> vertex (which occur oftenly on the alpha shape border).
>
>             --Ben
>
> On Fri, Apr 3, 2009 at 8:42 AM, naresh 
> <>
>  wrote:
>> Hi Omar
>>
>> Thanx for help... Your code helps me
>>
>>
>> Naresh
>>
>> ----- Original Message ----- From: "omar rodriguez"
>> <>
>> To: 
>> <>
>> Sent: Thursday, April 02, 2009 11:50 AM
>> Subject: Re: [cgal-discuss] Alpha Shape Question
>>
>>
>> Hello naresh
>>
>> you might find this of use
>>
>> https://lists-sop.inria.fr/sympa/arc/cgal-discuss/2009-03/msg00087.html
>>
>> Cheers
>>
>> Omar
>>
>> +
>>
>>
>>
>> On Wed, Apr 1, 2009 at 11:55 PM, naresh 
>> <>
>>  wrote:
>>>
>>> Hi
>>>
>>> Can i convert Alpha shape 3 to Polyhydron ?
>>>
>>> I looked at code for increment build of Polyhydron is this right method to
>>> build polyhydron from Alpha shape ?
>>>
>>> Basically I am building 3D mesh from points and I want simplify Alpha
>>> Shape
>>> with edge_collapse method so i need input as Polyhydron.
>>>
>>> Any good method ?
>>>
>>> naresh
>>
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