CGAL users discussion list

[Philipp Moeller <>]

Dongming Yan 
<>
 writes:

> Dear CGAL developers,
>
> I encounter a problem when I compute the intersection of two triangles who
> share a common vertex. Here is the debug information:
>
> CGAL error: precondition violation!
> Expression : ! s1.is_degenerate() && ! s1.is_degenerate()
> File: cgal-4.0\include\CGAL\Intersections_3/intersection_3_1_impl.h
> Line: 262
>
> I attached two test examples which cause the problem. Any idea how to fix
> the problem? Thanks in advance.

Classical question first: Which kernel are you using? If it isn't exact,
please see the FAQ [1].

Footnotes: 
[1]  http://www.cgal.org/FAQ.html#kernels