CGAL users discussion list

[Camille Wormser <>]

> Plane(f1->halfedge()->vertex()->point(),f1->halfedge()->next()- 
> >vertex()->point(),f1->halfedge()->prev()->vertex()- 
> >point())==Plane(f2->halfedge()->vertex()->point(),f2->halfedge()- 
> >next()->vertex()->point(),f2->halfedge()->prev()->vertex()->point())
>
> to check if two facets are in the same plane, it crashes with
>
> CGAL error: precondition violation!
> Expr: circulator_size(h->vertex_begin()) >= size_type(3)
> while trying to remove a halfedge

This means that you have degenerate faces, probably because some of  
the collapsing you did before was not acceptable, because the link  
condition was not satisfied.

> (because the facets are not coplanar).

I think it is not related. The error relates to the combinatorial  
structure.

> If I use f1->plane()==f2->plane(), it does not crash but does not  
> find any
> coplanar facets. Using typedef
> CGAL::Exact_predicates_inexact_constructions_kernel K; for both cases.
>
> I also changed the code to test first if they are adjacent and then  
> if they are
> coplanar, the problem remains...

By testing coplanarity, I mean calling CGAL::coplanar on the vertices,  
without computing the plane.
--
Camille