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[thierry Fernandez <>]

Ok, it's a godd news.

I d'ont know why, but my VC++ d'ont find the include Exact_integer.h

In fact i have a city with bulidings and streets , and the bounding box.

I have to cut the empty space in biggest convex volumes .

so i want to construct the scene with boolean operation on plane, and use convex decomposition of polyedrons.

2015-02-19 14:15 GMT+01:00 Sebastien Loriot (GeometryFactory) <>:

On 02/19/2015 02:08 PM, thierry Fernandez wrote:

I watched these pages, but why integers?

The example is using homogenous coordinates which is why an integer type is sufficient.
If you use CGAL::Extended_cartesian then you can use a rational type.

http://doc.cgal.org/latest/Nef_2/classCGAL_1_1Extended__cartesian.html

Side remark: if you're looking for the close intersection of a set of
halfspaces then a function doing exactly this will be included in the
next release of CGAL (the beta is expected before the end of the month).


Sebastien.

2015-02-19 11:29 GMT+01:00 Sebastien Loriot (GeometryFactory)
< <mailto:>>:

    On 02/19/2015 10:01 AM, thierry Fernandez wrote:

        ok but i want to construct Nef_Polyedron_3 with plane_3, and this 2
        kernels doesn't work.


    Sorry for not having guessed, my daughter broke my crystal ball
    recently.

    You're in the unlucky case where you indeed need to use an extended
    kernel like in this example:
    http://doc.cgal.org/latest/__Nef_3/index.html#Nef___3UsinganExtendedKernel
    <http://doc.cgal.org/latest/Nef_3/index.html#Nef_3UsinganExtendedKernel>
    See also:
    http://doc.cgal.org/latest/__Nef_3/index.html#sectionNef___3InfiBox
    <http://doc.cgal.org/latest/Nef_3/index.html#sectionNef_3InfiBox>

    Sebastien.


        2015-02-19 9:21 GMT+01:00 Sebastien Loriot (GeometryFactory)
        < <mailto:>
        <mailto: <mailto:>>>__:

             On 02/18/2015 04:14 PM, tfern90 wrote:

                 why so many kernel in cgal ????

             See http://www.cgal.org/FAQ.html#____kernels
        <http://www.cgal.org/FAQ.html#__kernels>
             <http://www.cgal.org/FAQ.html#__kernels
        <http://www.cgal.org/FAQ.html#kernels>>

             In practice,
        Exact_predicates_inexact_____constructions_kernel and
             Exact_predicates_exact_____constructions_kernel will fit
        most of the
             needs.

             Sebastien.



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