CGAL users discussion list

["Sebastien Loriot (GeometryFactory)" <>]

Since snap rounding in 3D is not easy, I think you should compute the
intersecting polyline using exact arithmetic and then simplify the output.
For the computation of intersecting polylines, you might want to
have a look at the non-documented function in 
CGAL/intersection_of_Polyhedra_3.h

template <typename Polyhedron, typename OutputIterator>
OutputIterator
intersection_Polyhedron_3_Polyhedron_3(const Polyhedron& P, const 
Polyhedron& Q, OutputIterator out)

where out expects object of type std::vector<typename Kernel::Point_3> 
representing a polyline

Sebastien.


On 03/07/2013 11:47 AM, Oleg wrote:
> Yes, more general shapes. The final goal is to make uniform meshes for
> bodies composed of general shapes with sharp boundaries between them.
>
> Oleg
>
> Thursday, March 7, 2013, 17:23, you wrote:
>  > What is the final goal? Only mesh 3 spheres? mesh n spheres? or more
>  > general shapes?
>
>  > I ask the question because the answer then varies.
>
>  > Sebastien.
>
>  > On 03/07/2013 11:16 AM, Oleg wrote:
>  >> Thursday, March 7, 2013, 16:53, you wrote:
>  >> > Le jeudi 07 mars 2013 00:00:11 Oleg a écrit :
>  >> >> Hello everyone! I have a question regarding triangulation
>  >> optimization. I
>  >> >> make a mesh for 3 balls intersection with 3 1D features. The mesh is
>  >> uniform
>  >> >> everywhere except 2 points where the 3 boundaries intersect:
>  >> >> <http://cgal-discuss.949826.n4.nabble.com/file/n4656843/3balls.gif>
>  >> >> These points don't seem to represent any problem for a manual
> meshing,
>  >> >> because the boundaries intersect at large angles. Is there any easy
>  >> way to
>  >> >> optimize the mesh around these points to avoid the unnecessary
>  >> crowding? Any
>  >> >> ideas will be greatly appreciated.
>  >>
>  >> > In your example, I assume that you have computed the intersections of
>  >> spheres
>  >> > and set them as 1D features of the domain. When 1D-features
>  >> intersect, you
>  >> > need to split them first at the intersection points. That will
> make the
>  >> > special intersections points as "corner points" of the domain, and
>  >> fix the
>  >> > crowding you see in the result.
>  >>
>  >> You're right, that's what I did. I'll try what you recommend, thanks!
>  >> Just another quick question - what would be the best way to find
>  >> intersection points of two polylines? Keeping in mind that the
>  >> polylines may not intersect in one exact point but rather pass by
>  >> each other at a small distance..?
>  >>
>  >> Oleg
>  >>
>  >>
>  >>
> ------------------------------------------------------------------------
>  >> View this message in context: Re[2]: Triangulation optimization around
>  >> special points
>  >>
> <http://cgal-discuss.949826.n4.nabble.com/Triangulation-optimization-around-special-points-tp4656843p4656846.html>
>
>  >> Sent from the cgal-discuss mailing list archive
>  >> <http://cgal-discuss.949826.n4.nabble.com/> at Nabble.com.
>
>
>
> ------------------------------------------------------------------------
> View this message in context: Re[4]: Triangulation optimization around
> special points
> <http://cgal-discuss.949826.n4.nabble.com/Triangulation-optimization-around-special-points-tp4656843p4656848.html>
> Sent from the cgal-discuss mailing list archive
> <http://cgal-discuss.949826.n4.nabble.com/> at Nabble.com.