CGAL users discussion list

[Ben Supnik <>]

Hi Efi,

> It requires exact constructions when it constructs new geometric object, 
> for example, intersections points. If, for example, the sweep line is 
> used to construct an arrangement of segments that do not intersect each 
> other in their interior, then exact constructions is not required. Exact 
> predicates are always required.

So if I understand correctly, the issue here is that internally sweep 
line always constructs intersections (when they exist) even if the 
visitor that is layered on top of it doesn't actually use them (e.g. 
"do_intersect", as opposed to "return the intersections")?

Out of curiosity, is it theoretically possible to code sweep-line only 
in terms of predicates on the source curve set (assuming the output 
format didn't need to return the intersections)?

cheers
ben