CGAL users discussion list

[Maarten Moesen <>]

Thank you, Sebastien.
I overlooked this feature because I was still working with version 4.10 (and 
its documentation). So I'm planning to upgrade soon 😉

Nice weekend!

Maarten

-----Original Message-----
From: 

 
<>
 On Behalf Of Sebastien Loriot (GeometryFactory)
Sent: Friday, 22 February, 2019 11:43
To: 

Subject: Re: [cgal-discuss] [EXTERNAL] Re: retrieve associated information 
with halfspaces after a halfspace intersection

Would this be sufficient:
https://urldefense.proofpoint.com/v2/url?u=https-3A__doc.cgal.org_latest_Convex-5Fhull-5F3_Convex-5Fhull-5F3-5F2extreme-5Findices-5F3-5F8cpp-2Dexample.html&d=DwICaQ&c=XEmjTyjfAPcP2RtAp-6FGA&r=m_cDzmT5gx2T28-wSEGolLNtn-S-ReoPoEIWT7yrZso&m=i8LVh5KRPscA4QVq8VepWDjbZG43LNRri4XyM97xaP0&s=J8TCWGY5Bkv78ABJorZYHFcFI6pkFyH9H7RFYgLdrUE&e=

or you need the convex hull as well?

Sebastien.

On 2/22/19 11:29 AM, Maarten Moesen wrote:
> Dear Sebastien,
> Dear CGAL community,
> 
> Thank you for your answer. Indeed, it doesn't look too hard.
> 
> I'm now having a similar question about convex_hull_3: what is the 
> recommended way to keep track of the vertices in the convex hull?
> For example: if I have originally a large vector or list of points, 
> possibly with some info associated with them. How can I efficiently 
> determine which points are in the convex hull? Can I access from the 
> resulting convex polyhedron the original iterator? Can I associate some 
> info to each point?
> 
> Best regards,
> 
> Maarten
> -----Original Message-----
> From: 
> 
>  
> <>
>  On 
> Behalf Of Sebastien Loriot (GeometryFactory)
> Sent: Friday, 22 February, 2019 09:50
> To: 
> 
> Subject: [EXTERNAL] Re: [cgal-discuss] retrieve associated information 
> with halfspaces after a halfspace intersection
> 
> With the current code there is no entry in the API. However it should not 
> be not hard to do it. Indeed, looking at the 
> halfspace_intersection_with_constructions_3.h for example, you'll see that 
> when a new face is created in build_dual_polyhedron (which is building the 
> dual of the dual, i.e. the final intersection) we iterate over vertices of 
> the convex hull of the dual (one vertex = one plane) so we could add a 
> property in the API to add that information.
> 
> Best regards,
> 
> Sebastien.
> 
> On 2/22/19 8:19 AM, Maarten Moesen wrote:
>> Dear CGAL community,
>>
>>   From a large vector of planes (halfspaces), in which each plane has 
>> some information attached, I'd like to create a convex polyhedron 
>> using
>>
>> CGAL::halfspace_intersection_3() and
>> halfspace_intersection_with_constructions_3().
>>
>> How can I efficiently identify in the resulting polyhedron which 
>> planes where selected, so that I can efficiently retrieve the 
>> information associated to each selected plane?
>>
>> Best regards,
>>
>> Maarten
>>
>> --
>>
>> Maarten Moesen, PHD
>>
>> Polymer Physicist Computational Modeling
>>
>> HUNTSMAN (Europe) BVBA
>>
>> Everslaan 45
>>
>> B-3078 Everberg
>>
>> Belgium
>>
>> VAT: BE - 0468.807.829
>>
>> Office Phone: 0032 (0) 2 758 9962
>>
> 
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