CGAL users discussion list

[Manuel Caroli <>]

Hi Issha,

Issha Kayo wrote:
> Hello everyone,
> 
> I've just started to use the periodic 3D Delaunay triangulation.
> 
> Using locate(Point), I could find a cell that contains the point. If the
> point locates quite near the boundary of the original cube, one or more
> of the four vertices of the cell might be wrapped to be contained in the
> original cube.
> The function point() seems to give me only the position in the original
> cube. Could you possibly show me how to access the position of vertices
> with offset? (say "1.1 0.1 0.1" but not "0.1 0.1 0.1").
> I found "offset()" but it returns "0 0 0". If it was "1 0 0" or
> something, I'm happy!
You should use the function periodic_point(Cell_handle, int) in
Periodic_3_triangulation_3 which returns a Periodic_point (point-offset
pair). Then you can convert it to a Point_3 using the function
point(Periodic_point). Beware that this function uses constructions, so
if you want it to be exact you would need to use a kernel that provides
exact constructions.
See also the reference documentation:
http://www.cgal.org/Manual/last/doc_html/cgal_manual/Periodic_3_triangulation_3_ref/Class_Periodic_3_triangulation_3.html

Best

Manuel