CGAL users discussion list

["Sebastien Loriot (GeometryFactory)" <>]

On 02/14/2013 05:14 PM, Chris Theis wrote:
> Hi Sebastien,
>
> my problem actually starts when I do the following:
>
> CGAL::Polyhedron_3<Kernel,CItemsEx>  TestPoly;                            // 
> CItemsEx is derived from Polyhedron_items_3 and extends vertices, faces&  halfedges
> CGAL::Nef_polyhedron_3<Kernel>   TestSolid( TestPoly );
>
> as long as I use
>
> CGAL::Polyhedron_3<Kernel, CGAL::Polyhedron_items_3>  TestPoly;
>
> it's ok. I found that the constructor of nef-polyhedra accepts only standard 
> Polyhedron_3 objects without an extended items classifier. I wanted to use the 
> extended items in order to have a convenient way to calculate and store normals 
> for vertices, faces&  halfedges as shown in one of the examples.
Could I see what is CItemEx?

> In principle I do not necessarily need nef-polyhedra if there is another 
> convenient way to do intersections, differences and unions of Polyhedron_3 
> objects. By definition all of my polyhedra should be closed. The only other 
> two requirements that I have is that I have to test if a point is included in 
> my polyhedron (and nef-polys provide a nice way to do this) and an 
> intersection query for rays.
>
> So if there is a different way to achieve this without using nef-polys then 
> I'll also be glad to give it a try.

You can use the AABB_tree for those tasks.
http://www.cgal.org/Manual/latest/doc_html/cgal_manual/AABB_tree/Chapter_main.html

Sebastien.

> I'm completely new to CGAL so I'm grateful for any information!
>
> Cheers
> Chris
>
>
> -----Original Message-----
> From: 
>
>  
> [mailto:]
>  On Behalf Of Sebastien Loriot (GeometryFactory)
> Sent: 14 February 2013 17:01
> To: 
>
> Subject: Re: [cgal-discuss] Extended polyhedra&  nef_polyhedra
>
> Do you have a minimal example showing the issue?
>
> Depending on what you need, you might be interested by the corefinement 
> plugin in the Polyhedron demo that performs boolean operations on Polyhedra 
> directly (select the two polyhedra in the A/B column). The constraint is that 
> the intersection polylines between the polyhedra are closed (including the 
> boundaries)
>
> Sebastien.
>
> On 02/14/2013 03:36 PM, Chris Theis wrote:
> > Hello,
> >
> > I'm currently trying to implement a module which needs to perform
> > boolean operations on polyhedra.
> > In general I'm using a class which is derived from CGAL::Polyhedron_3
> > for managing my solids and for the boolean ops I would like to convert
> > the polyhedra to nef_polyhedra and then back.
> >
> > If I do something like this:
> >
> >     CSGPolyhedron<Kernel, CGAL::Polyhedron_items_3>   TestPoly;
> >     CGAL::Nef_polyhedron_3<Kernel>   TestSolid( TestPoly );
> >
> > then the compiler is happy. However, I have extended my polyhedron
> > items so my actual conversion would look like:
> >
> >     CSGPolyhedron<Kernel, CItemsEx>   TestPoly;
> >     CGAL::Nef_polyhedron_3<Kernel>   TestSolid( TestPoly );
> >
> > CItemsEx is derived from CGAL::Polyhedron_items_3 and handles the
> > information for vertex&   face normals. However, when I'm using my
> > extended items then the compiler starts complaining:
> >
> > snc_structure.h(174): error C2903: 'Halffacet' : symbol is neither a
> > class template nor a function template ....and many more error
> > messages
> >
> > I could trace this problem back to the use of the extended items. In
> > principle I would not need the extended functionality within the nef
> > polyhedra. But I don't know how to do the conversion of my extended
> > polyhedron to the nef_polyhedron. The available constructors do not
> > seem to work.
> >
> > Is there any other way to do this? I'd greatly appreciate any hint in
> > this direction because I would really like to keep my extended items
> > for the polyhedra.
> >
> > Thanks a lot
> > Chris
> >
> >
> >
> >
> > --
> > View this message in context:
> > http://cgal-discuss.949826.n4.nabble.com/Extended-polyhedra-nef-polyhe
> > dra-tp4656726.html Sent from the cgal-discuss mailing list archive at
> > Nabble.com.
>
>
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