Skip to Content.
Sympa Menu

cgal-discuss - Re: [cgal-discuss] AABBTree primitives or objects problem

Subject: CGAL users discussion list

List archive

Re: [cgal-discuss] AABBTree primitives or objects problem


Chronological Thread 
  • From: Joe C <>
  • To:
  • Subject: Re: [cgal-discuss] AABBTree primitives or objects problem
  • Date: Fri, 4 Dec 2009 09:52:17 -0800
  • Domainkey-signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :content-type; b=WCoaBGblB4TMLy8YWq7GC2LyFHoOoMEojQ0M5k5RisMGYNo1JcXlel9ASbuSm28YrO 7pmxiioT6JsKCtM9o977MlgM+EfZpgeUe0alY+fGvoa2t4469iuG2N6IjqjhsvoRSd2W O79GV6c7A2PcHqCZhQ94GqZImJ/L5rpdaM+K0=

Hi Camille,

To add one more question in this thread:

Can I mix the use of Kernels in AABB tree? For example, use
exact_predicates_exact_constructions kernel for Polyhedron and
Simple_cartesian<double> for a segment to detect the intersection. I
used to use these two kernels for AABB tree in CGAL 3.4. But all the
examples I found in CGAL 3.5 use the same kernel for AABB tree and the
query geometry (ray, segment...).

Thanks.

Joe


On 12/3/09, Camille Wormser
<>
wrote:
>> the tree.number_of_intersected_primitives(Segment) gives me 5
>> intersections. But if I use the code to test what type of objects
>> are. only 3
>> are Point_3. What are the other 2?
>
> Hi Roberto,
> This is a typical robustness issue: I guess you use the
> exact_predicates_inexact_constructions kernel. In such a case, the
> do_intersect predicate used to answer the number_of_intersections
> query is exact. Hence the answer 5. On the other hand, the
> intersection constructions are not, and I suspect that they simply do
> not find any intersection for the two missing cases (I assume from
> your message that the code did not find any segment intersection).
>
> Of course, it would be better if the predicates and the constructions
> were consistent in the exact_predicates_inexact_constructions kernel
> (i.e. Always returning a non empty construction if the predicate said
> so). This is on some todo-list, but it is a delicate question. (note
> that it is not really AABB-tree related)
>
> Best
> --
> Camille
>
>
> --
> You are currently subscribed to cgal-discuss.
> To unsubscribe or access the archives, go to
> https://lists-sop.inria.fr/wws/info/cgal-discuss
>
>



Archive powered by MHonArc 2.6.16.

Top of Page