CGAL users discussion list

[Eric Berberich <>]

 wrote:
> Mahmood Naderan wrote:
> > > You have to give src+tgt. And three other points. A third point 
> > > defined only a unique circle. In addition, not every combination of 
> > > points defines a connected arc.
> >
> > Sorry I did not understand. What do you mean by src+tgt?
>
> source+target
> As Eric recalled, you need _5_ points to uniquely define a conic, 
> moreover, the 5 points do not always lie on the same arc of the conic.

Here, with "arc" a "connected subset in the affine plane" is meant.

> > Also will "CGAL::do_inersect" help me? according to manual, these types:
> > Polygon 2 Polygon with holes 2 General polygon 2
> > General polygon with holes 2
> >  
> > are supported by that function. So does this mean conic arc is not 
> > supported? (I think it is an abvious question)
>
> right, more generally there are no conics nor conic arcs supported in 
> the CGAL Kernels.
> As Eric said, you may find some functionality in Arr_conic_traits_2.h (a 
> traits class for CGAL arrangements), but _not_ in the kernel.

You should be at least able to define x-monotone conic arcs.


> Circular arcs (restricted case of conic arcs) are supported by the 2D 
> Circular Kernel. A circular arc can be uniquely defined by 3 points.

Maybe, you only need Circle .. ;-) check it.

eriC